Expressions of miR-21 TGF-beta/Smad signaling pathway in peripheral blood of bronchial asthma patients complicated with respiratory virus infection

OBJECTIVE: To investigate the expressions of peripheral blood microRNA-21(miR-21) and transforming growth factor-beta(TNF-beta)/Smad signaling transduction pathway in patients with bronchial asthma complicated with respiratory virus infection. METHODS: Totally 109 patients with asthma complicated with respiratory virus infection(study group) and 104 patients without virus infection(control group) in the Third People's Hospital of Gansu Province between Feb.2019 and Feb.2021 were selected for the cross-sectional study. The basic data of the two groups were collected, and parameters including vital signs, lung function, peripheral blood miR-21 and TGF-beta/Smad signaling pathway proteins were measured. According to the guidelines, the patients of the two groups were divided into acute exacerbation phase and stable phase. The examination results of each group were compared and the levels of peripheral blood miR-21 and TGF-beta/Smad signaling pathway proteins expression of patients with asthma complicated with respiratory virus infection were analyzed. RESULTS: In study group, the proportion of respiratory virus infection among 109 patients was 33.94% for influenza virus, 23.85% for human rhinovirus, 19.27% for respiratory syncytial virus, 10.09% for parainfluenza virus, 6.42% for adenovirus, 4.59% for human coronavirus and 1.83% for human metapneumovirus respectively. The proportion of patients with acute exacerbation phase in the study group was higher than that in the control group, and the levels of peripheral blood miR-21, TGF-beta1, Smad7, pSmad2 and pSmad3 were higher than those in control group(P<0.05). The levels of miR-21, TGF-beta1, Smad2, Smad3, Smad7, pSmad2 and pSmad3 in peripheral blood of patients with acute exacerbation phase of asthma were higher than those of patients with stable phase of asthma(P<0.05). There were no statistical differences in peripheral blood miR-21, TGF-beta1, Smad2, Smad3, Smad7, pSmad2 and pSmad3 levels in asthma patients with different virus infections. CONCLUSION: Early respiratory virus infections might lead to increased expression of peripheral blood miR-21 and increased activation of TGF-beta/Smad signaling pathway in patients with asthma, which played an important role in acute attack of asthma.

Characterization of Adaptive Immune Responses to SARS-CoV-2 Updated Bivalent Booster

Bivalent COVID-19 vaccines that contain two mRNAs encoding Wuhan-1 and Omicron BA.4/5 spike proteins are successful in preventing infection from the original strain and Omicron variants, but the quality of adaptive immune responses is still not well documented. This study aims at characterizing adaptive immune responses to the bivalent booster vaccination in 46 healthy participants. Plasma and PBMC were collected prior and three weeks after bivalent booster. We measured anti-N, anti-S, and RBD IgM, IgA, IgG plasma titers against original, Omicron BA.1, and BA.5 variants (pending) as well as total anti-S IgG titers and surrogate Virus Neutralization capacity against the Alpha, Delta, and BA.1 variant. With spectral flow-cytometry we identified peripheral blood B-cells specific for the RBD of the S-protein of the original and BA.1 variants. T-cell-specific responses were assessed by cytokine release assay after stimulation with SARS-CoV-2 peptides from the original, BA.1, BA.4, and BA.5 variants (pending). Finally, we performed TRB and IGH repertoire studies on sorted CD4+, CD8+, CD19+ lymphocytes, to study breadth of SARS-CoV-2 specific clonotypes (pending). 27/46 participants were analyzed;9 had SARS-CoV-2 infection (COVID+), while 18 are infection naive (COVID-). In both groups, median time since last dose of SARS-CoV-2 vaccine (3rd or 4th) was 11 months. All subjects were positive for anti-S IgG prior to bivalent booster. The COVID + group displayed anti-S IgG pre-booster levels and neutralization against BA.1 higher than the COVID- group. Significant increase post-boost of total anti-S IgG and BA.1 neutralizing activity was detected in the COVID- but not in the COVID+ group;however, no difference in neutralization activity post-boost was detected between the two groups. Furthermore, the COVIDgroup showed significant increase in the frequency of CD19+ and CD27+ switched memory B-cells specific for BA.1 RBD in post-boost compared to pre-boost samples. However, post-boost frequencies of the same B-cells were higher in the COVID+ compared to the COVID- group. These preliminary findings confirm that among individual immunized with the original COVID-19 mRNAvaccine, prior COVID infection provides increased protection against SARS-CoV-2 variants. They also demonstrate that booster immunization with the bivalent vaccine induces robust adaptive immune responses against Omicron variant.[Formula presented][Formula presented]Copyright © 2023 Elsevier Inc.

Dried Blood Spot Analyses for the Diagnosis of Anti-cytokine Autoantibodies

Background: High-titer neutralizing anti-cytokine autoantibodies have been shown to be involved in several acquired diseases, including pulmonary alveolar proteinosis, cryptococcal meningitis, and disseminated/extrapulmonary Nocardia infections (anti-GM-CSF autoantibodies), disseminated mycobacterial disease (anti-IFN-gamma autoantibodies), and some cases of severe COVID-19 infection (anti-type 1 interferons). Currently, patient blood samples are shipped via courier and require temperaturecontrolled conditions for transfer. This method is expensive and requires patients to have access to medical personnel to draw the blood. However, the well-established technique of collecting blood on a paper card as a dried blood spot (DBS) for diagnosis offers a point of care alternative which can be performed with a simple finger prick. This method is less invasive, cheaper, and allows for easy transport of patient samples. Method(s): 30 uL of whole blood from patients was blotted on filter paper and stored at 4C until use. The filter paper was hole punched and each punched spot was eluted with 150 uL of a 0.05% Tween PBS solution at room temperature overnight. The eluate was screened for anti-cytokine autoantibodies using a particle-based approach. Patient plasma was also screened in conjunction for comparison. Result(s): We confirmed the presence of autoantibodies in the DBS eluate from 4 previously diagnosed patients with anti-GM-CSF autoantibodies and 2 patients with anti-IFN-gamma autoantibodies. Functional studies showed the DBS eluate from a patient with anti-GM-CSF autoantibodies was able to block GM-CSF-induced STAT-5 phosphorylation in normal PBMC. As a proof of concept and to increase the number of patients evaluated, we also confirmed the presence of anti-cytokine autoantibodies using dried plasma eluate from 9 patients with known anti-GM-CSF autoantibodies and 9 patients with anti-IFN-gamma autoantibodies. Levels detected in DBS analyses were comparable to the levels found in plasma from the same patients not subjected to blotting and elution. Temperature studies showed that the autoantibodies were detected at similar levels when stored at 4C, 25C, and 40C for a week. Conclusion(s): The diagnosis of pathogenic anti-cytokine autoantibodies should be considered in the context of unusual or adult-onset infections, and screening for this diagnosis can be performed with dried blood spot testing.Copyright © 2023 Elsevier Inc.

A New Registry for Genetic Diagnosis of Inborn Errors of Immunity within the Military Health System

Genotypic definition of monogenic inborn errors of immunity (IEIs) continues to accelerate with broader access to next generation sequencing, underscoring this aggregated group of disorders as a major health burden impacting both civilian and military populations. At an estimated prevalence of 1 in 1200 individuals, IEIs affect ~8,000 patients within the Military Health System (MHS). Despite access to targeted gene/exome panels at military treatment facilities, most affected patients never receive a definitive genetic diagnosis that would significantly improve clinical care. To address this gap, we established the first registry of IEI patients within the MHS with the goal of identifying known and novel pathogenic genetic defects to increase diagnosis rates and enhance clinical care. Using the registry, a research protocol was opened in July 2022. Since July we have enrolled 75 IEI patients encompassing a breadth of phenotypes including severe and recurrent infections, bone marrow failure, autoimmunity/autoinflammation, atopic disease, and malignancy. Enrolled patients provide blood and bone marrow samples for whole genome, ultra-deep targeted panel and comprehensive transcriptome sequencing, plus cryopreservation of peripheral blood mononuclear cells for future functional studies. We are also implementing and developing analytical methods for identifying and interrogating non-coding and structural variants. Suspected pathogenic variants are adjudicated by a clinical molecular geneticist using state-of-the-art analysis pipelines. These analyses subsequently inform in vitro experiments to validate causative mutations using cell reporter systems and primary patient cells. Clinical variant validation and return of genetic results are planned with genetic counseling provided. As a proof of principle, this integrated genetic evaluation pipeline revealed a novel, candidate TLR7 nonsense variant in two adolescent brothers who both endured critical COVID-19 pneumonia, requiring mechanical ventilation and extracorporeal membrane oxygenation. Our protocol is therefore poised to greatly enrich clinical genetics resources available in the MHS for IEI patients, contributing to better diagnosis rates, informed family counseling, and targeted treatments that collectively improve the health and readiness of the military community. Moreover, our efforts should yield new mechanistic insights on immune pathogenesis for a broad variety of known and novel IEIs.Copyright © 2023 Elsevier Inc.

GENE ANALYSIS REVEALED THE USEFULNESS OF TRIPLE THERAPY WITH BARICITINIB, RITUXIMAB AND TACROLIMS FOR ANTI-MDA5 ANTIBODY POSITIVE DERMATOMYOSITIS (MDA5-DM)

BackgroundAnti-MDA5 antibody positive dermatomyositis (MDA5-DM) is characterized by high mortality due to rapid progressive ILD. MDA5 is a cytosolic protein and a family of RIG-I like receptor, which functions as a virus RNA sensor and induces the production of such as type-1 IFN. Although little is known about the pathogenesis of MDA5-DM, it is notable that the similarities were reported between COVID-19 infection and MDA5-DM. It may suggest that there is a common underlying autoinflammatory mechanism. We reported that in MDA5-DM, (1) RIG-I-like receptor signaling is enhanced and (2) antiviral responses such as type 1 IFN signaling are also enhanced as compare with anti-ARS-antibody positive DM, and (3) the key for survival is suppression of RIG-I-like and IFN signaling (EULAR2022, POS0390). We also found that a significant role for uncontrolled macrophage in the pathogenesis of ILD by our autopsy case. Recently, it has been reported that tacrolimus (TAC) and cyclophosphamide (CY) combination therapy (TC-Tx) has improved the prognosis of cases with early onset of the disease, but there are cases that cannot be saved. Therefore, we devised BRT therapy (BRT-Tx). The Tx combines baricitinib (BAR), which inhibits GM-CSF and IFN-mediated signaling and effectively suppresses uncontrolled macrophages, with rituximab (RTX) and TAC, which rapidly inhibits B and T cell interaction and ultimately prevents anti-MDA5 antibody production.ObjectivesTo determine the differences in gene expression between BRT and TC-Tx for MDA5-DM in peripheral blood.MethodsTotal of 6 MDA5-DM (TC: 3, BRT: 3) were included and all of them had multiple poor prognostic factors. Peripheral whole blood was collected at just before and 2-3 months after the treatment. RNA was extracted, and quantified using a next-generation sequencer. Differentially Expressed Genes (DEGs) were identified by pre vs. post treatment. Gene Ontology (GO), clustering and Gene Set Variation Analysis (GSVA) were performed to DEGs. As one BRT case was added since our last year's report, we also reanalyzed the surviving vs. fatal cases. The IFN signature was scored separately for Types 1, 2, and 3, and the changes between pre- and post-treatment were investigated.ResultsTwo of three cases with TC died during treatment, while all three cases on BRT recovered. The cluster analysis of the DEGs separated deaths from survivors, not by type of treatment. Comparing surviving and dead cases, GO analysis revealed that the immune system via immunoglobulins and B cells was significantly suppressed in surviving cases. GO analysis of DEGs in each therapeutic group showed that expression of B cell-related genes such as lymphocyte proliferation and B cell receptor signaling pathway were significantly suppressed in BRT-Tx. On the other hand, TC-Tx significantly suppressed such pathways as cell proliferation and cell surface receptor signaling, and was less specific for the target cells than BRT-Tx. The changes in IFN signature score after treatment showed an increase in type 2 and 3 IFN scores in all fatal cases and an increase in type 1 IFN score in one fatal case.ConclusionBRT-Tx significantly suppressed gene expression associated with B cells, while TC-Tx was characterized by low specificity of therapeutic targets and suppression of total cell proliferation. Comparison of surviving and dead cases revealed that the combination of RTX contributed to the success of treatment, as suppression of the immune system mediated by immunoglobulins and B cells is the key for survival. Analysis of the IFN signature revealed an increase in IFN score after treatment in fatal cases, indicating that the combination of BAR is beneficial. The superiority of BRT-Tx seems clear from the fact that all patients survived with BRT-Tx while only one/three patients survived with TC-Tx.REFERENCES:NIL.Acknowledgements:NIL.Disclosure of InterestsMoe Sakamoto: None declared, Yu Nakai: None declared, Yoshiharu Sato: None declared, Yoshinobu Koyama Speakers bureau: Abbvie, Asahikasei, Ayumi, BMS, Esai, Eli-Lilly, Mitsubishi Tanabe, Grant/research support from: Abbvie, GSK.

Establishment of an infrastructure for rapid pandemic response at the Frederick National Laboratory

The sudden onset of the 2019 SARS-CoV-2 pandemic required agile development of standards and efficient validation of assays to assess prevalence of infection as well as immune responses to infection and vaccination. Leveraging their experience in HPV serology and standards, the Vaccine, Immunity and Cancer Directorate (VICD) at the Frederick National Laboratory for Cancer Research (FNCLR) pivoted to address this unmet need in SARS-Co-V2 serology clinical testing and research. This standardization effort required the collection and processing of large volumes of blood from SARS-Co-V2 infected and uninfected individuals into serum and peripheral blood mononuclear cells (PBMCs). Collaborations with specimen collection sites across the United States were established. Following qualification for anti-SARS-CoV-2 IgG and IgM levels in independent laboratories, VICD assembled reference evaluation panels, which were used to assist the FDA's performance evaluation of commercial assays submitted for EUA approval. To date, 185 different shipments of the standard or validation panel have been sent to both domestic and international labs. These materials are also available to the SARS-CoV-2 serology community for assay calibration and performance evaluation which greatly facilitates assay data harmonization. In addition, the NCI Serological Sciences Network (SeroNet) was born from this initiative and expertise, resulting in the establishment of Capacity Building Centers (CBCs) for sample collection from different healthy, cancer and immunocompromised cohorts at Mount Sinai, Arizona State University, the University of Minnesota, and Northwell Feinstein. The NCI and FNLCR simultaneously collaborated to develop a network of investigators focused on advancing research on the immune response to SARS-CoV-2 infection and vaccination among diverse and vulnerable populations, including cancer patients. Their research has resulted in over 326 peer-reviewed publications. The CBC's have enrolled patients in longitudinal studies, resulting in a centralized collection of annotated, well characterized serum, PBMCs and clinical data. Numerous cancer cohorts, but predominantly Multiple Myeloma, are included. Furthermore, technology development was supported at the CBC's. Based upon this success, the VICD in collaboration with NCI is pursuing an even more innovative effort in pandemic preparedness to establish a Center for Serology and Data Emergency Preparedness (CESDEP);a global network able to activate and pivot to address pandemic-level threats, while continuing to expand the development of immunological assays that can inform clinical decisions for cancer and other immunocompromised patients.

TYPE I INTERFERON SCORE IS ASSOCIATED WITH THE SEVERITY AND POOR PROGNOSIS IN ANTI-MDA5 ANTIBODY-POSITIVE DERMATOMYOSITIS PATIENTS

BackgroundAnti-MDA5 antibody-positive dermatomyositis (anti-MDA5+DM) is a rare autoimmune disease associated with a high mortality rate due to rapid-progressive interstitial lung disease (RP-ILD), particularly in East Asia[1]. MDA5, acts as a cytoplasmic sensor of viral RNA, thus activating antiviral responses including the type I interferon (IFN) signaling pathway[2]. The involvement of type 1 IFN in the pathogenesis of MDA5+DM has been proposed based on the significantly elevated expression of its downstream stimulated genes(ISG) in muscle, skin, lung, and peripheral blood[3;4]. Janus kinase inhibitor, which targets the IFN pathway, combined with glucocorticoid could improve the survival of early-stage MDA5+DM-ILD patients[5]. In clinical practice, there is still an urgent demand for sensitive biomarkers to facilitate clinical risk assessment and precise treatment.ObjectivesThis study aimed to investigate the clinical significance of interferon score, especially IFN-I score, in patients with anti-MDA5+DM.MethodsDifferent subtypes of idiopathic inflammatory myopathy, including anti-MDA5+DM(n=61), anti-MDA5-DM(n=20), antisynthetase syndrome(ASS,n=22),polymyositis(PM,n=6) and immune-mediated necrotizing myopathy(IMNM,n=9), and 58 healthy controls were enrolled.. A multiplex quantitative real-time PCR(RT-qPCR) assay using four TaqMan probes was utilized to evaluate two type I ISGs (IFI44, MX1, which are used for IFN-I score), one type II ISG (IRF1), and one housekeeping gene (HRPT1). Clinical features and disease activity index were compared between high and low IFN-I score groups in 61 anti-MDA5+DM patients. The association between laboratory findings and the predictive value of baseline IFN-I score level for mortality was analyzed.ResultsThe IFN scores were significantly higher in patients with anti-MDA5+DM than in HC (Figure 1A). The IFN-I score correlated positively with serum IFN α(r = 0.335, P =0.008), ferritin (r = 0.302, P = 0.018), and Myositis Disease Activity Assessment Visual Analogue Scale (MYOACT) score(r=0.426, P=0.001). Compared with patients with low IFN-I scores, patients with high IFN-I scores showed increased MYOACT score, CRP, AST, ferritin, and the percentages of plasma cells (PC%) but decreased lymphocyte count, natural killer cell count, and monocyte count. The 3-month survival rate was significantly lower in patients with IFN-I score > 4.9 than in those with IFN-I score ≤ 4.9(72.9% vs. 100%, P=0.044)(Figure 1B).ConclusionIFN score, especially IFN-I score, detected by multiplex RT-qPCR, can be a valuable biomarker for monitoring disease activity and predicting mortality in anti-MDA5+DM patients.References[1]I.E. Lundberg, M. Fujimoto, J. Vencovsky, R. Aggarwal, M. Holmqvist, L. Christopher-Stine, A.L. Mammen, and F.W. Miller, Idiopathic inflammatory myopathies. Nat Rev Dis Primers 7 (2021) 86.[2]G. Liu, J.H. Lee, Z.M. Parker, D. Acharya, J.J. Chiang, M. van Gent, W. Riedl, M.E. Davis-Gardner, E. Wies, C. Chiang, and M.U. Gack, ISG15-dependent activation of the sensor MDA5 is antagonized by the SARS-CoV-2 papain-like protease to evade host innate immunity. Nat Microbiol 6 (2021) 467-478.[3]G.M. Moneta, D. Pires Marafon, E. Marasco, S. Rosina, M. Verardo, C. Fiorillo, C. Minetti, L. Bracci-Laudiero, A. Ravelli, F. De Benedetti, and R. Nicolai, Muscle Expression of Type I and Type II Interferons Is Increased in Juvenile Dermatomyositis and Related to Clinical and Histologic Features. Arthritis Rheumatol 71 (2019) 1011-1021.[4]Y. Ye, Z. Chen, S. Jiang, F. Jia, T. Li, X. Lu, J. Xue, X. Lian, J. Ma, P. Hao, L. Lu, S. Ye, N. Shen, C. Bao, Q. Fu, and X. Zhang, Single-cell profiling reveals distinct adaptive immune hallmarks in MDA5+ dermatomyositis with therapeutic implications. Nat Commun 13 (2022) 6458.[5]Z. Chen, X. Wang, and S. Ye, Tofacitinib in Amyopathic Dermatomyositis–Associated Interstitial Lung Disease. New England Journal of Medicine 381 (2019) 291-293.AcknowledgementsThis work was supported by the National Natural Science Foundation of China [81974251], and Shanghai Hospital Develop ent Center, Joint Research of New Advanced Technology Project [SHDC12018106]Disclosure of InterestsNone Declared.

Immunotherapy: OFF-THE-SHELF PARTIAL HLA MATCHING SARS-COV-2 ANTIGEN SPECIFIC T CELL THERAPY FOR SEVERE COVID-19 PATIENTS

Background & Aim: Immunological characteristics of COVID-19 show pathological hyperinflammation associated with lymphopenia and dysfunctional T cell responses. These features provide a rationale for restoring functional T cell immunity in COVID-19 patients by adoptive transfer of SARS-CoV-2 specific T cells. Methods, Results & Conclusion(s): To generate SARS-CoV-2 specific T cells, we isolated peripheral blood mononuclear cells from 7 COVID-19 recovered and 13 unexposed donors. Consequently, we stimulated cells with SARS-CoV-2 peptide mixtures covering spike, membrane and nucleocapsid proteins. Then, we culture expanded cells with IL-2 for 21 days. We assessed immunophenotypes, cytokine profiles, antigen specificity of the final cell products. Our results show that SARSCoV- 2 specific T cells could be expanded in both COVID-19 recovered and unexposed groups. Immunophenotypes were similar in both groups showing CD4+ T cell dominance, but CD8+ and CD3+CD56+ T cells were also present. Antigen specificity was determined by ELISPOT, intracellular cytokine assay, and cytotoxicity assays. One out of 14 individuals who were previously unexposed to SARS-CoV-2 failed to show antigen specificity. Moreover, ex-vivo expanded SARS-CoV-2 specific T cells mainly consisted of central and effector memory subsets with reduced alloreactivity against HLA-unmatched cells suggesting the possibility for the development of third-party partial HLA-matching products. In conclusion, our findings show that SARSCoV- 2 specific T cell can be readily expanded from both COVID-19 and unexposed individuals and can therefore be manufactured as a biopharmaceutical product to treat severe COVID-19 patients.Copyright © 2023 International Society for Cell & Gene Therapy

HLA-B evolutionary divergence is associated with poor outcomes after SARS-CoV-2 infection

Objectives Human leukocyte antigens (HLA) are highly diverse transmembrane proteins that present viral peptides to T cells and launch pathogen-specific immune responses. We aim to investigate the correlation between HLA evolutionary divergence (HED), a surrogate for the capacity to present different peptides, and the outcomes of SARS-CoV-2 infection in a cohort from the St. Louis Metropolitan area. Methods We enrolled adult patients with SARS-CoV-2 infection confirmed by RT-PCR who were hospitalized at two tertiary hospitals in St. Louis between March and July 2020. Genomic DNA was extracted from peripheral blood and genotyped by next-generation sequencing (NGS). HLA alleles were assigned based on key-exon sequences (G group) and limited to the 2-field resolution. HED was calculated by Grantham distance, which considers the difference in composition, polarity, and molecular volume between each pair of amino acids from maternal and paternal HLA. The HED score was obtained for HLA class I (HLA-A, -B, and -C) genotypes using the HLAdivR package in R. Clinical data were collected retrospectively from electronic medical records. A poor outcome was defined as an admission to the intensive care unit (ICU), a need for mechanical ventilation, or death. A favorable outcome was defined as the absence of the above poor outcomes. Results A total of 234 patients were enrolled in this study, 96 being females (41%). The median age and BMI were 66 years old and 28.30 kg/m2, respectively. African Americans comprised 71.4% of the cohort. Only 19 patients (8.1%) presented with no comorbidity;the rest had one or more comorbidities, with cardiovascular diseases being the most common. A total of 137 (58.5%) patients had poor outcomes from SARS-CoV-2 infection, while 97 (41.5%) patients had a favorable outcome. We detected a significant association between higher HLA-B HED and favorable outcomes, with each 1-point increase in HLA-B HED associated with 8% increased probability for the composite endpoint (OR 1.08, 95% CI=1.01-1.16, P = 0.04). The HED scores calculated for HLA-A or HLA-C were not significantly different between patients with favorable or poor outcomes. In a multivariate logistic regression analysis, increased HLA-B HED score, younger age, and no comorbidity were independently associated with favorable outcomes (P = 0.02, P = 0.01, and P = 0.05, respectively). Conclusion Our study shows a significant correlation between lower HLA-B HED scores and poor outcomes after SARS-CoV-2 infection. This finding suggests that maximizing the presentation of diverse SARS-CoV-2 peptides by HLA-B alleles may improve the clearance of SARS-CoV-2. Further studies are warranted to understand the functional and mechanistic implications of this finding.

"Actionable" host genetic markers for repurposing "add-on therapy" in COVID-19

Background/Objectives: COVID-19 still represents a lifethreatening disease in individuals with a specific genetic background. We successfully applied a new Machine Learning method on WES data to extract a set of coding variants relevant for COVID- 19 severity. We aim to identify personalized add-on therapy. Method(s): A subset of identified variants, "actionable" by repurposed drugs, were functionally tested by in vitro and in vivo experiments. Result(s): Males with either rare loss of function variants in the TLR7 gene or L412F polymorphism in the TLR3 gene benefit from IFN-gamma, which is specifically defective in activated PBMCs, restoring innate immunity. Females heterozygous for rare variants in the ADAMTS13 gene and males with D603N homozygous polymorphism in the SELP gene benefit from Caplacizumab, which reduces vWF aggregation and thrombus formation. Males with either the low-frequency gain of function variant T201M in CYP19A1 gene or with poly-Q repeats >=23 in the AR gene benefit from Letrozole, an aromatase inhibitor, which restores normal testosterone levels, reducing inflammation and which rescues male golden hamsters from severe COVID-19. Conclusion(s): By adding these commonly used drugs to standard of care of selected patients, the rate of intubation is expected to decrease consistently, especially in patients with high penetrance rare genetic markers, mitigating the effect of the pandemic with a significant impact on the healthcare system.

Cellular and Molecular Atlas of Peripheral Blood Mononuclear Cells from a Pregnant Woman after Recovery from COVID-19

Objective This study aimed to investigate the immune response of a pregnant woman who recovered from the coronavirus disease 2019 (COVID_RS) by using single-cell transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) and to analyze the properties of different immune cell subsets. Methods PBMCs were collected from the COVID_RS patient at 28 weeks of gestation, before a cesarean section. The PBMCs were then analyzed using single-cell RNA sequencing. The transcriptional profiles of myeloid, T, and natural killer (NK) cell subsets were systematically analyzed and compared with those of healthy pregnant controls from a published single-cell RNA sequencing data set. Results We identified major cell types such as T cells, B cells, NK cells, and myeloid cells in the PBMCs of our COVID_RS patient. The increase of myeloid and B cells and decrease of T cells and NK cells in the PBMCs in this patient were quite distinct compared with that in the control subjects. After reclustering and Augur analysis, we found that CD16 monocytes and mucosal-Associated invariant T (MAIT) cells were mostly affected within different myeloid, T, and NK cell subtypes in our COVID_RS patient. The proportion of CD16 monocytes in the total myeloid population was increased, and the frequency of MAIT cells in the total T and NK cells was significantly decreased in the COVID-RS patient. We also observed significant enrichment of gene sets related to antigen processing and presentation, T-cell activation, T-cell differentiation, and tumor necrosis factor superfamily cytokine production in CD16 monocytes, and enrichment of gene sets related to antigen processing and presentation, response to type II interferon, and response to virus in MAIT cells. Conclusion Our study provides a single-cell resolution atlas of the immune gene expression patterns in PBMCs from a COVID_RS patient. Our findings suggest that CD16-positive monocytes and MAIT cells likely play crucial roles in the maternal immune response against severe acute respiratory syndrome coronavirus 2 infection. These results contribute to a better understanding of the maternal immune response to severe acute respiratory syndrome coronavirus 2 infection and may have implications for the development of effective treatments and preventive strategies for the coronavirus disease 2019 in pregnant women.Copyright © Wolters Kluwer Health, Inc. All rights reserved.

Enhancer deregulation inTET2-mutant clonal hematopoiesis is associated with increased COVID-19 severity and mortality

Background: COVID-19 causes significant morbidity and mortality, albeit with considerable heterogeneity among affected individuals. It remains unclear which host factors determine disease severity and survival. Given the propensity of clonal hematopoiesis (CH) to promote inflammation in healthy individuals, we investigated its effect on COVID-19 outcomes. Method(s): We performed a multi-omics interrogation of the genome, epigenome, transcriptome, and proteome of peripheral blood mononuclear cells from COVID-19 patients (n=227). We obtained clinical data, laboratory studies, and survival outcomes. We determined CH status and TET2-related DNA methylation. We performed single-cell proteogenomics to understand clonal composition in relation to cell phenotype. We interrogated single-cell gene expression in isolation and in conjunction with DNA accessibility. We integrated these multi-omics data to understand the effect of CH on clonal composition, gene expression, methylation of cis-regulatory elements, and lineage commitment in COVID-19 patients. We performed shRNA knockdowns to validate the effect of one candidate transcription factor in myeloid cell lines. Result(s): The presence of CH was strongly associated with COVID-19 severity and all-cause mortality, independent of age (HR 3.48, 95% CI 1.45-8.36, p=0.005). Differential methylation of promoters and enhancers was prevalent in TET2-mutant, but not DNMT3A-mutant CH. TET2- mutant CH was associated with enhanced classical/intermediate monocytosis and single-cell proteogenomics confirmed an enrichment of TET2 mutations in these cell types. We identified celltype specific gene expression changes associated with TET2 mutations in 102,072 single cells (n=34). Single-cell RNA-seq confirmed the skewing of hematopoiesis towards classical and intermediate monocytes and demonstrated the downregulation of EGR1 (a transcription factor important for monocyte differentiation) along with up-regulation of the lncRNA MALAT1 in monocytes. Combined scRNA-/scATAC-seq in 43,160 single cells (n=18) confirmed the skewing of hematopoiesis and up-regulation of MALAT1 in monocytes along with decreased accessibility of EGR1 motifs in known cis-regulatory elements. Using myeloid cell lines for functional validation, shRNA knockdowns of EGR1 confirmed the up-regulation of MALAT1 (in comparison to wildtype controls). Conclusion(s): CH is an independent prognostic factor in COVID-19 and skews hematopoiesis towards monocytosis. TET2-mutant CH is characterized by differential methylation and accessibility of enhancers binding myeloid transcriptions factors including EGR1. The ensuing loss of EGR1 expression in monocytes causes MALAT1 overexpression, a factor known to promote monocyte differentiation and inflammation. These data provide a mechanistic insight to the adverse prognostic impact of CH in COVID-19.

Pandemic stress induces systemic immune changes and placental inflammation independently of SARS-CoV-2 infection in pregnancies

Problem: Environmental stress during pregnancy has known impacts on both maternal and fetal health. In terms of theCOVID-19 pandemic, the majority of published work has focused on the impact of the infection itself, without considering the potential immune impact of pandemic related-stress.We, therefore, assessed the impact of pandemic stress, independently of SARS-CoV-2 infection, on the circulating and placental immune profiles of pregnant individuals. Method(s): Placentas from 239 patients were collected at the Sainte- Justine Hospital, Montreal, Canada. Of these, 199 patients delivered during the pandemic and were exposed to pandemic stress with (+: 79) or without (-: 120) SARS-CoV-2 infection, the latter exposed to pandemic stress only. Pre-pandemic historic controls (uncomplicated pregnancies, Ctrl: 40), were also included. Placental biopsies were collected to assess cytokine levels by ELISAs and histopathological lesions. A sub-study with 35 pre-pandemic pregnancies (unexposed) and 20 who delivered during the pandemic (exposed) was also conducted. The latter (exposed/unexposed) were all uncomplicated pregnancies. We collected maternal blood prior to delivery for immunophenotyping, and plasma/peripheral blood mononuclear cells (PBMCs) were isolated. Inflammatory mediators in the plasma were quantified by ELISAs. Co-culture assays with PBMCs and human umbilical vein endothelial cells (HUVECs) were performed to assess endothelial activation. Demographical/obstetrical data were obtained through chart review. Result(s): SARS-CoV-2+ patients were multiethnic (63.4%), had higher pre-pregnancyBMI (28.9 vs. 24.8 inCtrl, P<.05), and elevated preterm birth rate (16.5% vs. 5.8% in SARS-CoV-2-, P < .05 and 0.0% in Ctrl, P < .01). In the placentas, we observed an increase in the levels of IL- 1Ra (P < .05) and CRP (P < .05) in both SARS-CoV-2 groups, while IL-6 (P = .0790) and MCP-1 (P < .001) were elevated solely in SARS-CoV- 2-. These changes were predominant in placentas with inflammatory lesions on histopathological analysis. Moreover, we observed elevated CD45+ cells (P < .001) in the placentas from both SARS-CoV-2 groups versus Ctrl. Considering that the differences we observed were important in the SARS-CoV-2- group, we performed a study solely on uncomplicated pregnancies, either exposed or unexposed to pandemic stress. At the systemic level, we observed a decrease in the percentage of Th2 cells (P < .001), leading to a pro-inflammatory Th1/Th2 imbalance in exposed individuals. Decreased Treg (P < .05) and Th17 (P < .05) versus unexposed was also observed. Surprisingly, decreased levels of circulating IL-6 (P < .05), MCP-1 (P < .01), and CRP (P<.05) were seen in exposed versus unexposed individuals. Finally,we observed increased secretion of ICAM, a marker of endothelial activation, solely in endothelial cells co-cultured with PBMCs from exposed individuals. Conclusion(s): Overall, placental inflammatory profiles differed between pregnant individuals exposed to pandemic stress with or without SARS-CoV-2 infection. Moreover, we observed that the pandemic stress exposed group presented a systemic pro-inflammatory bias. This highlights the need to understand the differences between the effects of pandemic-related stress and the added burden of SARS-CoV-2 infection itself on maternal and fetal health. Our work also supports an association between an increased risk of hypertension/ preeclampsia and SARS-CoV-2 infection that might be driven in part by pandemic-related stress.

SINGLE CELL MULTIOMIC PROFILING OF DISRUPTED REGULATORY NETWORKS IN COVID19 ASSOCIATED MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN

BackgroundChildren infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) usually present minimal symptoms or are asymptomatic. Nevertheless, a subset of children 2-6 weeks after the initial SARS-CoV-2 infection develops a postinfectious SARS-CoV-2-related multisystem inflammatory syndrome in (MIS-C). Recently, transient expansion of TRBV11-2 T cell clonotypes in MIS-C was associated with signatures of inflammation and T cell activation, however, the underlying pathophysiology of MIS-C is not fully understood [1].ObjectivesThe purpose of our project is to characterize the complexity of cell populations and capture cellular heterogeneity to uncover the regulatory networks and interactions that are disrupted during MIS-C flare with simultaneous profiling of gene expression and open chromatin regions from the same nuclei.MethodsSamples of peripheral blood mononuclear cells from patients with MIS-C diagnosed at the University Children's Hospital, University Medical Center Ljubljana, were collected during the initial presentation before any treatment and at 6-12 months in remission. The primary aim is to identify which regulatory networks are driving inflammation in MIS-C flare, for which we are performing single cell Multiome ATAC + Gene Expression Sequencing. To enable simultaneous profiling of epigenomic landscape and gene expression from the same nuclei, we are using Chromium Next GEM Single Cell Multiome ATAC + Gene Expression kit from 10X Genomics.ResultsWe included 32 patients with MIS-C from whom we collected paired blood samples during the initial presentation before treatment and at 6-12 months in remission. In single cell multiomic experiment we included 10 patients with paired samples, with the most viable cell count prior cryopreservation. All samples that are included into multiomic single cell analysis have 75% - 99% viability prior cryopreservation. In the protocol the key is to remove remaining granulocytes causing high mitochondrial RNA burden and extensively optimize the dilution factor of lysis buffer and the length of cell lysis step in order to get intact nuclei with no significant blebbing. Afterward, the single cell ATAC libraries as well as single-cell gene expression libraries are constructed and sequenced. Data are undergoing pairwise analysis to compare the cell population heterogeneity, expression profile and open chromatin landscape in the time of the initial presentation of MIS-C and in the remission, with Cell ranger software as well as with R package scREG [2], and custom scripting. In the second step we will inspect if the resulting altered transcriptomic signature from single-cell experiment is present on larger cohort. In that regard, we will perform bulk transcriptomic profiling on all paired collected samples during the initial presentation of MIS-C before treatment and at 6-12 months in remission.ConclusionThe results of this project are expected to enlighten the underlying pathophysiology of MIS-C flare and thus support clinical decision on more targeted treatment. The identified disrupted networks during MIS-C flare could lead the way to establish an early diagnosis and improve long-term outcome, including prevention of myocardial and neuropsychological impairment. Moreover, a better understanding of the disrupted regulatory networks that are driving inflammation in MIS-C, could lead to new insights into diseases with similar clinical presentations as is Kawasaki Disease.References[1]Sacco, K., Castagnoli, R., Vakkilainen, S. et al. Immunopathological signatures in multisystem inflammatory syndrome in children and pediatric COVID-19. Nat Med 28, 1050–1062 (2022).[2]Duren, Z., Chang, F., Naqing, F. et al. Regulatory analysis of single cell multiome gene expression and chromatin accessibility data with scREG. Genome Biol 23, 114 (2022).AcknowledgementsThis research was supported by Slovenian research agency grant J3-3061 and Interreg ITA-SLO project Cattedra.Disclosure of InterestsNone Declared.

Antiviral activity of the human endogenous retrovirus-R envelope protein against SARS-CoV-2

Coronavirus-induced disease-19 (COVID-19), caused by SARS-CoV-2, is still a major global health challenge. Human endogenous retroviruses (HERVs) represent retroviral elements that were integrated into the ancestral human genome. HERVs are important in embryonic development as well as in the manifestation of diseases, including cancer, inflammation, and viral infections. Here, we analyze the expression of several HERVs in SARS-CoV-2-infected cells and observe increased activity of HERV-E, HERV-V, HERV-FRD, HERV-MER34, HERV-W, and HERV-K-HML2. In contrast, the HERV-R envelope is downregulated in cell-based models and PBMCs of COVID-19 patients. Overexpression of HERV-R inhibits SARS-CoV-2 replication, suggesting its antiviral activity. Further analyses demonstrate the role of the extracellular signal-regulated kinase (ERK) in regulating HERV-R antiviral activity. Lastly, our data indicate that the crosstalk between ERK and p38 MAPK controls the synthesis of the HERV-R envelope protein, which in turn modulates SARS-CoV-2 replication. These findings suggest the role of the HERV-R envelope as a prosurvival host factor against SARS-CoV-2 and illustrate a possible advantage of integration and evolutionary maintenance of retroviral elements in the human genome.Copyright © 2023 The Authors.

Single-Cell Analysis Reveals Characteristics of Myeloid Cells in Pulmonary Pasc

Background: Although our understanding of immunopathology in the risk and severity of COVID-19 disease is evolving, a detail of immune response in long-term consequences of COVID-19 infection remains unclear. Recently, few studies have detailed the immune and cytokine profiles associated with PASC. However, dysregulation of immune system driving pulmonary PASC is still largely unknown. Method(s): To characterize the immunological features of PPASC, we performed droplet-based scRNA-sequencing using 10X genomics to study the transcriptomic profiles of peripheral blood mononuclear cells (PBMCs) from participants naive to SARS-CoV-2 (NP, n=2) and infected with SARS-CoV-2 with chronic pulmonary symptoms (PPASC, n=2). Result(s): Analysis of more than 34,000 PBMCs by integrating our dataset with previously reported control datasets generated cell distribution and identified 11 immune cell types based on canonical gene expression. The proportion of myeloid-lineage cells (CD14+monocyte, CD16+monocyte, and dendritic cells) and platelets were increased in PPASC compared with those of NP. Specifically, PPASC displayed up-regulation of VEGFA and transcription factors, such as ATF2, ELK, and SMAD in myeloid-lineage cells. Also, TGF-beta and WNT signaling pathways were up-regulated in these cell population. Cell-cell interaction analysis identified that myeloid-lineage cells in PPASC participated in regulation of fibrosis and immune response, such as VEGFA (increased) and MIF (decreased) interactions. Conclusion(s): Together, this study provides high-resolution insights into immune landscape in PPASC. Our results emphasize differences in myeloid lineage-mediated fibrosis and immunity between PPASC and NP, suggesting they could act as potential pathological drivers of PPASC. (Figure Presented).

Fresh Versus Cryopreserved Allograft Outcomes in Peripheral Blood Stem Cell Transplantations

Background: The emergence of the COVID-19 pandemic saw an increased use of cryopreserved (cryo) peripheral blood (PB) grafts for allogeneic hematopoietic stem cell transplantation (HSCT). Outcomes of patients receiving either fresh or cryo grafts have yielded heterogeneous results. Herein, we retrospectively compared the outcomes of patients receiving fresh and cryo grafts at a single center.(Table Presented)Methods: Between 2019 and 2021, we reviewed data from 380 patients;167 (44%) received a fresh, and 213 (56%) received a cryo graft. Patients underwent myeloablative or nonmyeloablative HSCT from either matched or mismatched, related or unrelated donors. Cell doses were determined by number of donor cells collected and recipient weight at infusion. Engraftment, disease risk (DR) and acute GVHD were classified based on established criteria. Donor chimerism was collected at approximately day 28 and day 80 after HSCT. Unadjusted and adjusted estimates of overall survival (OS), relapse, and non-relapse mortality (NRM) as a function of time were obtained. The adjusted odds (grades III-IV acute GVHD) and the adjusted cause-specific hazard of failure (all other outcomes) were compared between the 2 groups. with the use of logistic (Figure Presented) or Cox regression, respectively. These models were adjusted for various factors known to be associated with each outcome. Result(s): The characteristics of patients between the 2 groups are shown in Table 1. There was a higher proportion of patients with high/very high DR in the fresh graft group (Table 1). Median time to neutrophil engraftment was 17 and 18 days in fresh vs. cryo, respectively. The adjusted hazard ratio (HR) of neutrophil engraftment (fresh vs. cryo) was 1.07 (95% CI, 0.86-1.34, p=0.54). Median time to platelet engraftment was 13 and 15 days, respectively, and the adjusted HR of platelet engraftment was 1.32 (1.06-1.65, p=0.01). Day 28 chimerism data were available for 272 patients (113 fresh and 159 cryo). At day 28, donor CD3 chimerism was below 50% in 5 out of 113 (4.4%) and 17 out of 159 (10.7%) patients receiving fresh and cryo grafts, respectively (p= 0.06). At day 80, 3 out of 121 (2.5%) patients in the fresh group and 4 out of 165 (2.4%) in the cryo group had CD3 chimerism below 50%. The adjusted HRs (fresh vs. cryo) for death and NRM were 0.83 (0.54-1.28, p=0.40) and 0.71 (0.38-1.33, p=0.29), respectively (Figures 1 and 2). The adjusted HR for relapse was 0.65 (0.42-0.99, p=0.05) (Figure 3). The adjusted odds ratio (fresh vs. cryo) for grades III-IV GVHD was 1.65 (0.94-2.9, p=0.07). Conclusion(s): In this single-center retrospective study we observed numerically better outcomes with fresh grafts relative to cryo grafts for all examined endpoints with the exception of grades III-IV aGVHD, although none of the differences were definitive with the possible exception of relapse and platelet engraftment. Further studies are needed to confirm our observations.Copyright © 2023 American Society for Transplantation and Cellular Therapy

HIGH-RESOLUTION MAPPING OF T-CELL HYBRID IMMUNITY TO THE ENTIRE SARS-CoV-2 PROTEOME

Background: To understand T-cell responses to SARS-CoV-2, it is essential to define the contribution of infection versus immunization to virus-specific hybrid immunity. Here, we characterized the breadth and magnitude of T-cell responses to the entire SARS-CoV2 proteome over a 2-year follow-up period in infected and vaccinated (CoV2+Vac+) and vaccinated and infected (Vac+CoV2+) individuals. Method(s): We selected samples from 38 (19 CoV2+ and 19 CoV2-, time1, T1) ProHEpiC-19 cohort participants, a prospective, longitudinal study starting in March 2020 involving 7,776 healthcare workers in Spain. Longitudinal samples were available from 10 of them after a 3-dose mRNA vaccination, including 5 CoV2+Vac+ and 5 Vac+CoV2+, at 824.5 and 250.5 days from symptoms onset (DfSO, time 2, T2). We measured the breadth and magnitude of IFN-y T-cell responses by ELISpot assay in cryopreserved PBMCs, using a 15-mer overlapping peptide (OLP) library of 2,790 SARS-CoV-2 peptides in 100 pools. Result(s): We identified immunodominant T-cell responses in S1, S2, nsp3, Env, NC, and M proteins across the SARS-CoV2 proteome. We observed an increased breadth of T-cell responses (responding pools over the entire region) to S1 (44 - 30%) and S2 (31 - 40%) in CoV2+Vac+ and Vac+CoV2+, respectively. In addition, CoV2+Vac+ had an exclusive and sustained response to M. We found significantly stronger responses in CoV2+Vac+ (P=0.0313). Particularly the total magnitude was greater in CoV2+Vac+ vs. Vac+CoV2+ in S1 (4476.88 vs. 1498.53), Env (457.34 vs. 250.50), and M (455.13 vs. 0.00) but not in S2 and nsp3. The total number of peptides for deconvolution was higher in CoV2+Vac+ (32 peptides) than in Vac+CoV2+ (3 peptides) during the follow-up. Seventy-five percent of the responses targeted S, and 25% M, ORF1a, and Env. Conclusion(s): These results profile immunodominant T-cell responses in S1, S2, nsp3, Env, NC, and M proteins across the entire SARS-CoV2 proteome. The data delineate differences in the number of T-cell responses primed hybrid immunity by infection previous to vaccination (CoV2+Vac+), being broader and of higher magnitude and underlining an exclusive T-cell response to the M region. Overall, these findings identify differences in long-term T-cell hybrid immunity primed by infection or vaccination, which may have implications in protection from re-infection and vaccine design.

Covid-19 Vaccination Impacts Functional Immune Responses and Plasma Proteome in Plwh

Background: The impact of COVID-19 infection or COVID-19 vaccination on the immune system of people living with HIV (PLWH) is unclear. We therefore studied the effects of COVID-19 infection or vaccination on functional immune responses and systemic inflammation in PLWH. Method(s): Between 2019 and 2021, 1985 virally suppressed, asymptomatic PLWH were included in the Netherlands in the 2000HIV study (NCT039948350): 1514 participants enrolled after the start of the COVID-19 pandemic were separated into a discovery and validation cohort. PBMCs were incubated with different stimuli for 24 hours: cytokine levels were measured in supernatants. ~3000 targeted plasma proteins were measured with Olink Explore panel. Past COVID-19 infection was proven when a positive PCR was reported or when serology on samples from inclusion proved positive. Compared were unvaccinated PLWH with and without past COVID-19 infection, and PLWH with or without anti-COVID-19 vaccination excluding those with past COVID-19 infection. Result(s): 471 out of 1514 participants were vaccinated (median days since vaccination: 33, IQR 16-66) and 242 had a past COVID-19 infection (median days since +PCR: 137, IQR 56-206). Alcohol, smoking, drug use, BMI, age, latest CD4 count and proportion with viral blips were comparable between groups. Systemic inflammation as assessed by targeted proteomics showed 89 upregulated and 43 downregulated proteins in the vaccinated participants. In contrast, individuals with a past COVID-19 infection display lower levels of 138 plasma proteins compared to the uninfected group (see figure). 'Innate immune system' and 'cell death' were upregulated in pathway analysis in vaccinated PLWH, but downregulated in COVID-19 infected participants. The increased systemic inflammation of the COVID-19 vaccinated group was accompanied by lower TNF-alpha and IL-1beta production capacity upon restimulation with a range of microbial stimuli, while production of IL-1Ra was increased. In COVID-19 infected PLWH only a reduced production of TNF-alpha to S. pneumonia was significant. Vaccinated PLWH also showed upregulation of platelet aggregation pathways. Conclusion(s): COVID-19 vaccination in PLWH leads to an increased systemic inflammation, but less effective cytokine production capacity of its immune cells upon microbial stimulation. This pattern is different from that of COVID-19 infection that leads to a decreased inflammatory profile and only minimal effects on cytokine production capacity. (Figure Presented).

CHRONIC HIV INFECTION IMPACTS THE IMMUNE RESPONSE DURING ACUTE SARS-CoV-2

Background: SARS-CoV-2 infection typically causes self-limited disease, but a subset of individuals experience more severe disease associated with respiratory manifestations, hospitalization and mortality. People living with HIV (PLWH) have been shown to have chronic immune activation and inflammation despite effective antiretroviral therapy. During the COVID pandemic, PLWH were found to have an increased risk of hospitalization and mortality with acute COVID-19. The immune response driving these worsened outcomes in PLWH is not defined. We analyzed immune activation and exhaustion markers, as well as antigen specific T cell responses during acute COVID-19 in PLWH versus HIV-seronegative controls to determine the impact of chronic HIV infection and inflammation on acute COVID-19. Method(s): We performed flow cytometric analyses on peripheral blood mononuclear cells from: 1) PLWH with acute COVID-19 (HIV+COVID), 2) HIVseronegative individuals with acute COVID-19 (COVID) and 3) pre-COVID-19 pandemic PLWH (HIV). COVID(+) samples were collected at an average of 4.7 (range 0-16) and 5.5 (range 0-20) days post-symptom onset for the COVID and HIV+COVID cohorts, respectively. Cells were stained for surface markers of activation/exhaustion and intracellular cytokines (with and without SARS-CoV- 2-specific antigen stimulation). Observed immune responses were correlated with disease severity. Result(s): PLWH with acute COVID-19 had increased classical (CD14+) monocytes compared to HIV-seronegative individuals with acute COVID-19. The HIV+COVID cohort also had higher expression of activation (OX40, CD137) and exhaustion (PD1, TIGIT) markers on CD4+ and CD8+ T cells compared to HIV-seronegative individuals. SARS-CoV-2 antigen stimulation resulted in similar response frequencies between the HIV+COVID and COVID cohorts. Conclusion(s): PLWH had increased activation and exhaustion and increased classical monocytes compared to HIV-seronegative presentations of COVID-19, highlighting the persistent immune dysregulation associated with chronic HIV infection. Our findings aid in further characterization of how chronic immune dysregulation impacts the immune response to acute SARS-CoV-2 infection. Future studies include characterizing the impact of acute SARS-CoV-2 infection duration, as well as how chronic immune dysregulation impacts the development of long COVID. (Table Presented).