Alterations in the CD56- and CD56+ T Cell Subsets during COVID-19.

The effectiveness of the antiviral immune response largely depends on the activation of cytotoxic T cells. The heterogeneous group of functionally active T cells expressing the CD56 molecule (NKT-like cells), that combines the properties of T lymphocytes and NK cells, is poorly studied in COVID-19. This work aimed to analyze the activation and differentiation of both circulating NKT-like cells and CD56- T cells during COVID-19 among intensive care unit (ICU) patients, moderate severity (MS) patients, and convalescents. A decreased proportion of CD56+ T cells was found in ICU patients with fatal outcome. Severe COVID-19 was accompanied by a decrease in the proportion of CD8+ T cells, mainly due to the CD56- cell death, and a redistribution of the NKT-like cell subset composition with a predominance of more differentiated cytotoxic CD8+ T cells. The differentiation process was accompanied by an increase in the proportions of KIR2DL2/3+ and NKp30+ cells in the CD56+ T cell subset of COVID-19 patients and convalescents. Decreased percentages of NKG2D+ and NKG2A+ cells and increased PD-1 and HLA-DR expression levels were found in both CD56- and CD56+ T cells, and can be considered as indicators of COVID-19 progression. In the CD56- T cell fraction, increased CD16 levels were observed in MS patients and in ICU patients with lethal outcome, suggesting a negative role for CD56-CD16+ T cells in COVID-19. Overall, our findings suggest an antiviral role of CD56+ T cells in COVID-19.

A retrospective analysis of first-line PD-1 monoclonal antibodies treatment in patients with leptomeningeal metastasis from solid tumors.

INTRODUCTION: Patients whose solid tumors (ST) show leptomeningeal metastasis (LM) have very poor prognosis and short overall survival. The aim of this study was to evaluate the efficacy of first-line programed death-1(PD-1) monoclonal antibody (mAb) treatment in these patients. METHODS: We retrospectively evaluated patients diagnosed with LM from ST who were treated with first-line PD-1 mAb at our hospital between April 1 and November 30, 2019. We analyzed their clinicopathological characteristics and response to the treatment. RESULTS: We collected and analyzed data from 6 patients with different primary ST. 5 patients received PD-1 mAb combined with chemotherapy and/or anti-angiogenic drugs, while one received only PD-1 mAb. The median (range) number of treatment cycles was 5.5 (1-21). PD-1 mAb treatment did not cause neurotoxicity. The time period of first assessment varied from 21 to 65 days after treatment. Among 5 patients who got obvious symptoms relief, 4 patients persisted for > 3 months and even showed a reduction in the number of tumor cells in cerebrosprinal fluid. Ventriculoperitoneal (VP) shunt was used to treat hydrocephalus observed beneficial in 3 patients: 2 before and 1 after PD-1 mAb treatment. The median (range) follow-up time was 214 (57-460) days. 4 patients died. The overall survival ranged from 57 days to at least 460 days. 1 of the two alive patients continued to show no worsening of symptoms after 457 days. CONCLUSIONS: Patients with LM from ST can benefit from first-line PD-1 mAb combined treatment without additional neurotoxicity. Further research is required to validate the safety and efficacy.

Chronic HIV infection influences the immune response during acute COVID-19 and long COVID

OBJECTIVES/GOALS: Despite highly effective antiretroviral therapy, people living with HIV (PLWH) experience chronic immune activation and inflammation which may influence the progression of infections such as SARS-CoV-2. Here, we explore the immune response and clinical outcomes in HIV(+) and HIV(-) individuals experiencing acute COVID-19 and long COVID (LC). METHODS/STUDY POPULATION: We performed flow cytometric analyses on peripheral blood mononuclear cells from the following: 1) HIV(-) individuals experiencing acute COVID-19, 2) PLWH experiencing acute COVID-19, and 3) pre-COVID-19 pandemic PLWH. Additionally, we will perform similar analyses for the following: 1) PLWH experiencing LC, 2) PLWH previously infected with SARS-CoV-2 who recovered, 3) pre-COVID-19 pandemic PLWH, and 4) HIV(-) individuals experiencing LC. Flow cytometry panels include surface markers for immune cell populations, activation and exhaustion surface markers (with and without SARS-CoV-2-specific antigen stimulation), and intracellular cytokine staining. We will also analyze how chronic HIV infection and other clinical and demographic factors (e.g., age, CD4 %) impact persistent symptomatic burden. RESULTS/ANTICIPATED RESULTS: Acute COVID-19 results–Overall, PLWH had higher baseline expression of activation markers OX40 and CD137 on CD4+ and CD8+ T cells, along with increased levels of TNFa producing CD8+ T cells. Interestingly, PLWH had increased expression of exhaustion markers PD1 and TIGIT but decreased expression of TIM3 on CD4+ and CD8+ T cells. Additionally, PLWH had decreased levels of IL-2 and IFNg producing CD4+ T cells which suggests functional exhaustion. Long COVID-19 expected results–we hypothesize that the activation and inflammation seen in chronic HIV infection will lead to more immune dysregulation and subsequently worsened symptomatic burden. Additionally, we hypothesize that PLWH may have different frequencies of certain LC manifestations, such as increased rates of neurocognitive impairment. DISCUSSION/SIGNIFICANCE: Our findings suggest that chronic HIV infection influences acute immune response during SARS-CoV-2 infection, and that PLWH have variable expression of exhaustion markers which warrants further study. Additionally, our findings in the LC cohort will aid in characterizing clinical manifestations and immunologic mechanisms of LC in PLWH.

The Role of Lymphocyte Subsets, PD-1, and FAS (CD95) in COVID-19 Cancer Patients.

Lymphocytes are the main orchestrators that regulate the immune response in SARS-COV-2 infection. The exhaustion of T lymphocytes is a contributing factor to lymphopenia, which is responsible for the COVID-19 adverse outcome. However, it is still not demonstrated on a large scale, including cancer patients. Peripheral blood samples were obtained from 83 SARS-CoV2 infected cancer patients, and 29 COVID-19 infected noncancer patients compared to 28 age-matched healthy controls. Lymphocyte subsets were assessed for CD3, CD4, CD8, CD56, PD-1, and CD95 using flow cytometry. The data were correlated to the patients' clinical features, COVID-19 severity and outcomes. Lymphopenia, and decreased CD4+ T cells and CD8+ T cells were significantly observed in COVID-19 cancer and noncancer patients compared to the control group (p < 0.001, for all). There was a significantly increased expression of CD95 and PD-1 on the NK cells, CD4+ T cells, and CD8+ T cells in COVID-19 cancer and noncancer patients in comparison to the control group. The increased expression of CD95 on CD8+ T cells, as well as the increased expression of PD-1 on CD8+ T cells and NK cells are significantly associated with the severity of COVID-19 infection in cancer patients. The increased expression of CD95 and PD-1 on the CD4+ T cells, CD8+ T cells, and NK cells was observed significantly in nonsurviving patients and those who were admitted to the intensive care unit in COVID-19 cancer and noncancer patients. The increased expression of PD-1 and CD95 could be possible prognostic factors for COVID-19 severity and adverse outcomes in COVID-19 cancer and noncancer patients.

The Association of Programmed Death 1 Gene Polymorphisms of PD1.3 G/A and PD1.5 C/T with Risk of COVID-19 in an Iranian Population: A Case-Control Study.

Programmed death 1 (PD-1) has a central role in maintaining T cell tolerance and terminating cellular responses after eliminating antigens. Variation in PD-1 gene products caused by polymorphisms has been linked to several malignancies and autoimmune diseases. However, there is little known about the effects of its single-nucleotide polymorphisms (SNPs) on viral infections, particularly COVID-19. The primary aim of this study was to explore the function of genotypes, alleles, and haplotypes of two SNPs within the programmed cell death protein 1 (PDCD1) gene at PD1.3 G/A and PD1.5 C/T on susceptibility to COVID-19 in an Iranian population. The secondary objective was to evaluate the effects of these SNPs on the outcome of the disease. We got blood samples from COVID-19 patients (n = 195) and healthy subjects (n = 500) for genotypic determination of PD1.3 G/A (rs11568821) and PD1.5 C/T (rs2227981) SNPs, using the polymerase chain reaction-restriction fragment length polymorphism method, and constructed four haplotypes for PDCD1 SNPs. We used Pearson's chi-squared test, Fisher's exact test, and T-test for this study and incorporated effect sizes of odds ratio (OR) and standardized mean difference. The frequency of CT genotype of PD1.5 was meaningfully higher in COVID-19 patients (49.2%) than in healthy subjects (37.4%) (p = 0.005). However, these significant differences were not observed in the frequencies of PD1.3 genotypes between the two groups (p > 0.05). Of all estimated haplotypes for PDCD1, only AT was significantly and largely associated with COVID-19 susceptibility (p = 0.01, OR: 7.79 [95% confidence interval = 1.56-38.79]), however, this finding is inconclusive. In addition, the present study showed that the PD1.3 and PD1.5 SNPs were not associated with the outcome of the disease (p > 0.05). These results may propose that the PD1.5 CT genotype and AT haplotype of PDCD1 indecisively contribute to COVID-19 susceptibility in the Iranian population.

Apatinib combined with camrelizumab in advanced acral melanoma patients: An open-label, single-arm phase 2 trial.

BACKGROUND: At present, immune monotherapy and combination therapy has not shown satisfactory effects on acral melanoma, and still no standard treatment is available for advanced acral melanoma. Here, a phase II trial was performed to explore the safety and efficacy of apatinib combined with camrelizumab in advanced acral melanoma patients as first-line therapy (NCT03955354). METHODS: Patients with pathologically confirmed, locally unresectable or metastatic treatment native acral melanoma received 250 mg apatinib once daily and camrelizumab 200 mg once every two weeks intravenously every 28-day cycle. The primary end-point was objective response rate and the secondary end-points were disease control rate, overall survival, progression-free survival and safety. RESULTS: Thirty patients were recruited between January 2015 and January 2022. Among them, 21 (70.0%) had stage IV, and a median tumour burden was 50 mm (range: 11-187). Objective response rate was 24.1%, and 7 of 29 patients had an anti-tumour response, including partial response (n = 5) and complete response (n = 2). Disease control rate was 82.8%, median progression-free survival was 7.39 months (confidence interval: 3.65-9.92), and median overall survival was 13.4 months (confidence interval: 1.9-25.0). Grade 3-4 treatment-related toxicity (grade 3 50.5%; grade 4 3.3%) included transaminase elevations, proteinuria, leukocytopenia, vomiting, diarrhea and drug-induced liver injury. No treatment-related mortality occurred. The mutations of TTN, MUC16, VPS13D, ALPK2 and SCUBE1 showed significant alterations with survival outcome. CONCLUSIONS: Apatinib combined with camrelizumab showed manageable safety profile and reasonable anti-tumour activity in advanced acral melanoma patients as first-line therapy.

SARS-CoV-2 infection in patients with melanoma: results of the Spanish Melanoma Group registry.

BACKGROUND: The Spanish Melanoma Group (GEM) developed a national registry of patients with melanoma infected by SARS-CoV-2 ("GRAVID"). METHODS: The main objective was to describe the COVID-19 fatality rate in patients with melanoma throughout the pandemic, as well as to explore the effect of melanoma treatment and tumor stage on the risk of COVID-19 complications. These are the final data of the register, including cases from February 2020 to September 2021. RESULTS: One hundred-fifty cases were registered. Median age was 68 years (range 6-95), 61 (40%) patients were females, and 63 (42%) patients had stage IV. Thirty-nine (26%) were on treatment with immunotherapy, and 17 (11%) with BRAF-MEK inhibitors. COVID-19 was resolved in 119 cases, including 85 (57%) patients cured, 15 (10%) that died due to melanoma, and 20 (13%) that died due to COVID-19. Only age over 60 years, cardiovascular disorders, and diabetes mellitus increased the risk of death due to COVID-19, but not advanced melanoma stage nor melanoma systemic therapies. Three waves have been covered by the register: February-May 2020, August-November 2020, and December 2020-April 2021. The first wave had the highest number of registered cases and COVID-19 mortality. CONCLUSION: Tumor stage or melanoma treatments are non-significant prognostic factors for COVID-19 mortality. During the pandemic in Spain there was a downward trend in the number of patients registered across the waves, as well as in the severity of the infection. GOV IDENTIFIER: NCT04344002.

Changes in PD-1- and CTLA-4-bearing blood lymphocytes in ICU COVID-19 patients treated with Favipiravir/Kaletra or Dexamethasone/Remdesivir: a pilot study.

COVID-19, caused by SARS-CoV-2, requires new approaches to control the disease. Programmed cell death protein (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) play important roles in T-cell exhaustion in severe COVID-19. This study evaluated the frequency of whole blood lymphocytes expressing PD-1 and CTLA-4 in COVID-19 patients upon admission to the intensive care unit (ICU) (i.e., severe) or infection ward (i.e., moderate) and after 7 days of antiviral therapy. COVID-19 patients were treated with either favipiravir or Kaletra (FK group, 11 severe and 11 moderate) or dexamethasone plus remdesivir (DR group, 7 severe and 10 moderate) for 7 days in a pilot study. Eight healthy control subjects were also enrolled. The frequency of PD-1+ and CTLA-4+ lymphocytes in whole blood was evaluated by flow cytometry. Patients on DR therapy had shorter hospital stays than those on FK therapy. The frequency of PD-1+ lymphocytes in the FK group at baseline differed between COVID-19 patients and healthy controls, while the frequency of both PD-1+ and CTLA-4+ cells increased significantly 7 days of FK therapy. The response was similar in both moderate and severe patients. In contrast, the frequency of PD-1+ and CTLA-4+ lymphocytes varied significantly between patients and healthy controls before DR treatment. DR therapy enhanced PD-1+ but not the CTLA-4+ frequency of these cells after 7 days. We show that the frequency of PD-1 and CTAL-4-bearing lymphocytes during hospitalization was increased in Iranian ICU COVID-19 patients who received FK treatment, but that the frequency of CTLA-4+ cells was higher at baseline and did not increase in patients who received DR. The effectiveness of DR treatment may reflect differences in T-cell activation or exhaustion status, particularly in CTLA-4-expressing cells.

Dressing Bacteria With a Hybrid Immunoactive Nanosurface to Elicit Dual Anticancer and Antiviral Immunity.

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections such as coronavirus disease 2019, are highly desirable but prove to be difficult. Here, dressing bacteria with a hybrid immunoactive nanosurface is reported to elicit dual anticancer and antiviral immunity. A combination of a checkpoint blocking antibody and a virus-specific antigen is covalently conjugated to polydopamine nanoparticles, which can be anchored onto bacterial surface, by a one-step in situ polymerization of dopamine under a cell-friendly condition. By virtue of the ability to colonize and penetrate deep tumor tissue, dressed bacteria enable sustained release and expanded exposure of carried immunoactivators to stimulate immune cells. In addition to a carrier role, bacteria are able to further provoke innate immunity due to the native immunogenicity of the pathogen-associated molecular patterns. Immunization with dressed bacteria promotes the maturation, and activation of antigen-presenting cells, which induces robust humoral and cellular immune responses in tumor-bearing mice. As evidenced by efficient production of viral-antigen-specific immunoglobulin G antibody in serum and significantly suppressed tumor growth in different models, dressing bacteria with a hybrid immunoactive nanosurface paves an avenue to prepare next-generation therapeutics for synergistic treatment and prevention.

PD-1highCXCR5-CD4+ peripheral helper T cells promote CXCR3+ plasmablasts in human acute viral infection.

T cell-B cell interaction is the key immune response to protect the host from severe viral infection. However, how T cells support B cells to exert protective humoral immunity in humans is not well understood. Here, we use COVID-19 as a model of acute viral infections and analyze CD4+ T cell subsets associated with plasmablast expansion and clinical outcome. Peripheral helper T cells (Tph cells; denoted as PD-1highCXCR5-CD4+ T cells) are significantly increased, as are plasmablasts. Tph cells exhibit "B cell help" signatures and induce plasmablast differentiation in vitro. Interestingly, expanded plasmablasts show increased CXCR3 expression, which is positively correlated with higher frequency of activated Tph cells and better clinical outcome. Mechanistically, Tph cells help B cell differentiation and produce more interferon γ (IFNγ), which induces CXCR3 expression on plasmablasts. These results elucidate a role for Tph cells in regulating protective B cell response during acute viral infection.

Evaluation of Tcell exhaustion based on the expression of EOMES, Tbet and co-inhibitory receptors in severe and non-severe covid-19 patients.

During viral infections, especially Covid-19, Tcell exhaustion plays a crucial role in reducing the activity of lymphocytes and the immune system's antiviral activities. This research aimed to investigate the co-inhibitory receptors and transcription factors involved in the Tcell exhaustion process in ICU-admitted (ICUA) compared to non-ICU admitted (non-ICUA) Covid-19 patients. A total of 60 Covid-19 patients (30 patients in the severe group who were admitted in the ICU (ICUA) and 30 patients in the mild group who were admitted in departments other than the ICU (non-ICUA)) and 10 healthy individuals were included in this study. Laboratory tests and the level of gene expressions related to 4 inhibitory co-receptors, including LAG-3, TIM-3, TIGIT, PD-1, and T-bet and Eomes transcription factors involved in the process of Tcell exhaustion in severe and mild patients of Covid-19 were investigated. The results showed lymphopenia and an increase in other hematologic laboratory factors such as NLR, PLR, CRP, ALT, and AST in people with a severe form of the disease (ICUA) compared to mild groups (non-ICUA) (P < 0.001). Furthermore, a significant increase in 3 co-inhibitory receptors, TIM-3, LAG-3, and PD-1, was observed in severe patients compared to mild and healthy people (P < 0.001). An increase in TIGIT gene expression was lesser than the other three mentioned receptors (P < 0.05). Concerning the transcription factors, we observed a significant increase in Eomes in ICUA patients compared to the non-ICUA group (P < 0.001), and this increment in T-bet gene expression was minor compared to Eomes (P < 0.05). In conclusion, Patients with a severe form of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represented a higher level of gene expressions in terms of co-inhibitory receptors and transcription factors involved in the T cell exhaustion process.

How does SARS-CoV-2 infection impact on immunity, procession and treatment of pan cancers.

We identified 14 immune-related differentially Expressed Genes (DEGs) between COVID-19 patients and normal controls and the receiver operator characteristic curve results showed that they could be used to discriminate COVID-19 patients from healthy controls. Single-sample gene set enrichment analysis and CIBERSORT analysis displayed immune landscape of COVID-19 patients that the fraction of immune cells (like B cell subtypes and T cell subtypes) decreased distinctly in the first SARS-CoV-2 infection which may further weaken immunity of cancer patients and increasing inflammatory cells (Neutrophils and Macrophages) may further promote inflammatory response of cancer patients. Based on expression levels of 14 DEGs we found that first SARS-CoV-2 infection may accelerate progression of cancer patients by Kaplan-Meier survival, immune subtypes and tumor microenvironment analyses, and may weaken anti-PD-1 monoclonal antibody treatment effect of cancer patients by weighted gene co-expression network, tumor mutation burden and microsatellite instability analysis. The second SARS-CoV-2 infection was beneficial to control development of tumor seemingly, but it may be difficult for cancer patients to experience destroy successfully from first SARS-CoV-2 infection, let alone benefits from second SARS-CoV-2 infection. In addition, this study also emphasized significance of multi-factor analysis when analyzing impacts of SARS-CoV-2 infection on cancer patients.

PD-1 and ICOS counter-regulate tissue resident regulatory T cell development and IL-10 production during flu.

Regulatory T cells that express the transcription factor Foxp3 (Treg cells) are a highly heterogenous population of immunoregulatory cells critical for maintaining immune homeostasis and preventing immunopathology during infections. Tissue resident Treg (TR-Treg) cells are maintained within nonlymphoid tissues and have been shown to suppress proinflammatory tissue resident T cell responses and promote tissue repair. Human populations are repetitively exposed to influenza infections and lung tissue resident effector T cell responses are associated with flu-induced long-term pulmonary sequelae. The kinetics of TR-Treg cell development and molecular features of TR-Treg cells during repeated and/or long-term flu infections are unclear. Utilizing a Foxp3RFP/IL-10GFP dual reporter mouse model along with intravascular fluorescent in vivo labeling, we characterized the TR-Treg cell responses to repetitive heterosubtypic influenza infections. We found lung tissue resident Treg cells accumulated and expressed high levels of co-inhibitory and co-stimulatory receptors post primary and secondary infections. Blockade of PD-1 or ICOS signaling reveals that PD-1 and ICOS signaling pathways counter-regulate TR-Treg cell expansion and IL-10 production, during secondary influenza infection. Furthermore, the virus-specific TR-Treg cell response displayed distinct kinetics, when compared to conventional CD4+ tissue resident memory T cells, during secondary flu infection. Our results provide insight into the tissue resident Foxp3+ regulatory T cell response during repetitive flu infections, which may be applicable to other respiratory infectious diseases such as tuberculosis and COVID.

In Vitro Exposure of Primary Human T Cells and Monocytes to Polyclonal Stimuli Reveals a Basal Susceptibility to Display an Impaired Cellular Immune Response and Develop Severe COVID-19.

The contribution of the cellular immune response to the severity of coronavirus disease 2019 (COVID-19) is still uncertain because most evidence comes from patients receiving multiple drugs able to change immune function. Herein, we conducted a prospective cohort study and obtained blood samples from 128 unvaccinated healthy volunteers to examine the in vitro response pattern of CD4+ and CD8+ T cells and monocyte subsets to polyclonal stimuli, including anti-CD3, anti-CD28, poly I:C, severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) recombinant spike S1 protein, and lipopolysaccharide. Then, we started a six-month follow-up and registered 12 participants who got SARS-CoV-2 infection, from whom we retrospectively analyzed the basal immune response pattern of T cells and monocytes. Of the 12 participants infected, six participants developed mild COVID-19 with self-limiting symptoms such as fever, headache, and anosmia. Conversely, six other participants developed severe COVID-19 with pneumonia, respiratory distress, and hypoxia. Two severe COVID-19 cases required invasive mechanical ventilation. There were no differences between mild and severe cases for demographic, clinical, and biochemical baseline characteristics. In response to polyclonal stimuli, basal production of interleukin-2 (IL-2) and interferon (IFN-) gamma significantly decreased, and the programmed cell death protein 1 (PD-1) increased in CD4+ and CD8+ T cells from participants who posteriorly developed severe COVID-19 compared to mild cases. Likewise, CD14++CD16- classical and CD14+CD16+ non-classical monocytes lost their ability to produce IFN-alpha in response to polyclonal stimuli in participants who developed severe COVID-19 compared to mild cases. Of note, neither the total immunoglobulin G serum titers against the virus nor their neutralizing ability differed between mild and severe cases after a month of clinical recovery. In conclusion, using in vitro polyclonal stimuli, we found a basal immune response pattern associated with a predisposition to developing severe COVID-19, where high PD-1 expression and low IL-2 and IFN-gamma production in CD4+ and CD8+ T cells, and poor IFN-alpha expression in classical and non-classical monocytes are linked to disease worsening. Since antibody titers did not differ between mild and severe cases, these findings suggest cellular immunity may play a more crucial role than humoral immunity in preventing COVID-19 progression.

Role of the PD-1 and PD-L1 axis in COVID-19.

Tweetable abstract Severe COVID-19 patients display dysregulated expression of checkpoint molecules PD-1 and its ligand PD-L1, suggesting that these checkpoint molecules could be considered as prognostic markers and therapeutic targets in severe cases of COVID-19.

A Δ42PD1 fusion-expressing DNA vaccine elicits enhanced adaptive immune response to HIV-1: the key role of TLR4.

Since its discovery in the 1990s, the DNA vaccine has been of great interest because of its ability to elicit both humoral and cellular immune responses while showing relative advantages regarding producibility, stability and storage. However, when applied to human subjects, inadequate immunogenicity remains as the greatest challenge for the practical use of DNA vaccines. In this study, we generated a DNA vaccine Δ42PD1-P24 encoding a fusion protein comprised of the HIV-1 Gag p24 antigen and the extracellular domain of murine Δ42PD1, a novel endogenous Toll-like receptor 4 (TLR4) agonist. Using a mouse model, we found that Δ42PD1-P24 DNA vaccine elicited a higher antibody response and an increased number of IFN-γ-producing CD4 and CD8 T cells. Moreover, mice with Δ42PD1-P24 DNA vaccination were protected from a subcutaneous challenge with murine mesothelioma cells expressing the HIV-1 p24 antigen. Importantly, the Δ42PD1-mediated enhancement of immune responses was not observed in TLR4 knockout mice. Collectively, these data demonstrate that the immunogenicity and efficacy of DNA vaccines could be improved by the fusion of the extracellular domain of Δ42PD1 to target the immunogen to dendritic cells.

Multiple Sclerosis and MEN2 Neoplasia in a Female Patient: A Unique Co-Existence with Expanded Immunological Interest and Therapeutical Challenges, before and after Patient's COVID-19 Infection.

Multiple sclerosis (MS) and its various comorbidities that may be observed are of great interest due to the complexity of MS pathophysiology and all of the immunological changes that follow. The incidence of cancer in MS has been investigated for several years, as not only does it affect ongoing therapeutical decisions, but also, certain disease-modifying treatments (DMTs) may increase the risk of tumorigenesis. For the first time, we present a case of a female patient with pediatric-onset MS (POMS) and multiple endocrine neoplasia 2B (MEN2B) and analyze the immunological impact of these diseases on the therapeutical choice, under the umbrella of her COVID-19 infection and the SARS-CoV-2 pandemic as a whole. We also review the existing literature regarding the immunogenetic and immunological correlations between these two extremely rare diseases and discuss the most suitable treatment for our case, which seems to be an anti-CD20 agent due to a better outcome in putative MS worsening and tumor progression, when killer immunoglobulin-like receptors' (KIR) expression is reduced in natural killer (NK) cells. We also broaden our concerns on this comorbidity issue, at the same time focusing on the future research needed in this unexplored field of the comorbidity of MS and cancers.

Robust Preanalytical Performance of Soluble PD-1, PD-L1 and PD-L2 Assessed by Sensitive ELISAs in Blood.

The interaction between programmed death-1 receptor PD-1 and its ligands PD-L1 and PD-L2 is involved in self-tolerance, immune escape of cancer, cardiovascular diseases, and COVID-19. As blood-based protein markers they bear great potential to improve oncoimmunology research and monitoring of anti-cancer immunotherapy. A variety of preanalytical conditions were tested to assure high quality plasma sample measurements: (i) different time intervals and storage temperatures before and after blood centrifugation; (ii) fresh samples and repeated freeze-thaw-cycles; (iii) different conditions of sample preparation before measurement. Concerning short-term stability, acceptable recoveries for PD-1 between 80 and 120% were obtained when samples were kept up to 24 h at 4 and 25 °C before and after blood centrifugation. Similarly, recoveries for PD-L2 were acceptable for 24 h at 4 °C and 6 h at 25 °C before blood centrifugation and up to 24 h at 4 and 25 °C after centrifugation. Variations for PD-L1 were somewhat higher, however, at very low signal levels. Sample concentrations (ng/mL) were neither affected by the freezing process nor by repeated freeze-thaw cycles with coefficients of variation for PD-1: 9.1%, PD-L1 6.8%, and PD-L2 4.8%. All three biomarkers showed good stability regarding preanalytic conditions of sample handling enabling reliable and reproducible quantification in oncoimmunology research and clinical settings of anti-cancer immunotherapy.

Dynamic Evaluation of Natural Killer Cells Subpopulations in COVID-19 Patients.

The aim of the study was to evaluate the dynamic changes of the total Natural Killer (NK) cells and different NK subpopulations according to their differentiated expression of CD16/CD56 in COVID-19 patients. Blood samples with EDTA were analyzed on day 1 (admission moment), day 5, and day 10 for the NK subtypes. At least 30,000 singlets were collected for each sample and white blood cells were gated in CD45/SSC and CD16/CD56 dot plots of fresh human blood. From the lymphocyte singlets, the NK cells subpopulations were analyzed based on the differentiated expression of surface markers and classified as follows: CD16-CD56+/++/CD16+CD56++/CD16+CD56+/CD16++CD56-. By examining the CD56 versus CD16 flow cytometry dot plots, we found four distinct NK sub-populations. These NK subtypes correspond to different NK phenotypes from secretory to cytolytic ones. There was no difference between total NK percentage of different disease forms. However, the total numbers decreased significantly both in survivors and non-survivors. Additionally, for the CD16-CD56+/++ phenotype, we observed different patterns, gradually decreasing in survivors and gradually increasing in those with fatal outcomes. Despite no difference in the proportion of the CD16-CD56++ NK cells in survivors vs. non-survivors, the main cytokine producers gradually decline during the study period in the survival group, underling the importance of adequate IFN production during the early stage of SARS-CoV-2 infection. Persistency in the circulation of CD56++ NK cells may have prognostic value in patients, with a fatal outcome. Total NK cells and the CD16+CD56+ NK subtypes exhibit significant decreasing trends across the moments for both survivors and non-survivors.

Navigating the cellular landscape in tissue: Recent advances in defining the pathogenesis of human disease.

Over the past decade, our understanding of human diseases has rapidly grown from the rise of single-cell spatial biology. While conventional tissue imaging has focused on visualizing morphological features, the development of multiplex tissue imaging from fluorescence-based methods to DNA- and mass cytometry-based methods has allowed visualization of over 60 markers on a single tissue section. The advancement of spatial biology with a single-cell resolution has enabled the visualization of cell-cell interactions and the tissue microenvironment, a crucial part to understanding the mechanisms underlying pathogenesis. Alongside the development of extensive marker panels which can distinguish distinct cell phenotypes, multiplex tissue imaging has facilitated the analysis of high dimensional data to identify novel biomarkers and therapeutic targets, while considering the spatial context of the cellular environment. This mini-review provides an overview of the recent advancements in multiplex imaging technologies and examines how these methods have been used in exploring pathogenesis and biomarker discovery in cancer, autoimmune and infectious diseases.