SARS-CoV-2 Viral Clearance and Evolution Varies by Extent of Immunodeficiency (preprint)

Despite vaccination and antiviral therapies, immunocompromised individuals are at risk for prolonged SARS-CoV-2 infection, but the immune defects that predispose to persistent COVID- 19 remain incompletely understood. In this study, we performed detailed viro-immunologic analyses of a prospective cohort of participants with COVID-19. The median time to nasal viral RNA and culture clearance in the severe hematologic malignancy/transplant group (S-HT) were 72 and 21 days, respectively, which were significantly longer than clearance rates in the severe autoimmune/B-cell deficient (S-A), non-severe, and non-immunocompromised groups (P<0.001). Participants who were severely immunocompromised had greater SARS-CoV-2 evolution and higher risk of developing antiviral treatment resistance. Both S-HT and S-A participants had diminished SARS-CoV-2-specific humoral, while only the S-HT group had reduced T cell-mediated responses. This highlights the varied risk of persistent COVID-19 across immunosuppressive conditions and suggests that suppression of both B and T cell responses results in the highest contributing risk of persistent infection.

SARS-CoV-2 virologic rebound with nirmatrelvir-ritonavir therapy (preprint)

Abstract Objective: To compare the frequency of replication-competent virologic rebound with and without nirmatrelvir-ritonavir treatment for acute COVID-19. Secondary aims were to estimate the validity of symptoms to detect rebound and the incidence of emergent nirmatrelvir-resistance mutations after rebound. Design: Observational cohort study. Setting: Multicenter healthcare system in Boston, Massachusetts. Participants: We enrolled ambulatory adults with a positive COVID-19 test and/or a prescription for nirmatrelvir-ritonavir. Exposures: Receipt of 5 days of nirmatrelvir-ritonavir treatment versus no COVID-19 therapy. Main Outcome and Measures: The primary outcome was COVID-19 virologic rebound, defined as either (1) a positive SARS-CoV-2 viral culture following a prior negative culture or (2) two consecutive viral loads [≥]4.0 log10 copies/milliliter after a prior reduction in viral load to <4.0 log10 copies/milliliter. Results: Compared with untreated individuals (n=55), those taking nirmatrelvir-ritonavir (n=72) were older, received more COVID-19 vaccinations, and were more commonly immunosuppressed. Fifteen individuals (20.8%) taking nirmatrelvir-ritonavir experienced virologic rebound versus one (1.8%) of the untreated (absolute difference 19.0% [95%CI 9.0-29.0%], P=0.001). In multivariable models, only N-R was associated with VR (AOR 10.02, 95%CI 1.13-88.74). VR occurred more commonly among those with earlier nirmatrelvir-ritonavir initiation (29.0%, 16.7% and 0% when initiated days 0, 1, and [≥]2 after diagnosis, respectively, P=0.089). Among participants on N-R, those experiencing rebound had prolonged shedding of replication-competent virus compared to those that did not rebound (median: 14 vs 3 days). Only 8/16 with virologic rebound reported worsening symptoms (50%, 95%CI 25%-75%); 2 were completely asymptomatic. We detected no post-rebound nirmatrelvir-resistance mutations in the NSP5 protease gene. Conclusions and Relevance: Virologic rebound occurred in approximately one in five people taking nirmatrelvir-ritonavir and often occurred without worsening symptoms. Because it is associated with replication-competent viral shedding, close monitoring and potential isolation of those who rebound should be considered.

Factors Affecting the Need for a Second HPC(A) Collection in Unrelated Allogenic Transplants: Process Improvement Opportunity

Introduction: Matched unrelated donors (MUD) for hematopoietic progenitor cell (HPC) transplantation are facilitated through the National Marrow Donor Program. Most peripheral blood collections (HPC-A) are obtained in a single day apheresis collection. Extensive planning is required to coordinate the mobilization, collection, and shipment of the product with the conditioning and infusing at the transplant center. Typically, these products are infused fresh, although the COVID pandemic has necessitated cryopreservation in many instances. It was perceived that the number of two-day MUD collections was increasing at our institution. This study was performed to determine if this was true and to evaluate potential causes. Method(s): The project was considered a laboratory quality improvement project;IRB approval was not required per institutional guideline. Data was collected retrospectively for 120 HPC(A) MUD from August 2017-November 2020 including donor's age, weight, and sex, along with recipient to donor weight ratio. Each factor was analyzed against CD34 yield per day of collection. Result(s): Of the 120 donors, 5.6% collected over 2 days in 2017(n=1), 3.7 % (n=1, 2018), 3.6 % (n=1, 2019) with highest observation 17% (n=8) in 2020 (Image). Donor age, donor weight, donor sex, and recipient to donor weight ratio were compared to absolute CD34 yield. There was not a correlation seen between CD34 yield and donor age nor weight. However, donor sex along with recipient/donor weight ratio each showed a correlation in the number of collections required. Of those requiring a second day of collection, 73% were female while 27% were male. Two-day collections could be predicted with 83% accuracy in female with >1.09 recipient/donor weight ratio and male with > 1.49 recipient/donor weight ratio.(Figure Presented) Conclusion(s): The observed trend of increased 2-day NMDP collections coincided with an increase in frequency of female donors. Not surprisingly, higher recipient/donor weight was associated with a higher likelihood of 2-day collections. The size and scope of this study do not allow us to determine a definitive cause. However, it was noted these findings coincided with new donor selection guidelines prioritizing HLA-DP match potentially leading to an increase in female donors being selected. Unexpected two-day collection can have significant effects on transplantation. Developing a predictive algorithm with 83% accuracy allows for patient and staff preparation to anticipate the likelihood for additional collections. Having the product collected and received in advance, prior to patient conditioning improves logistics and removes some variability from scheduling. Larger, multicenter studies are required to determine if increased numbers of two-day collection of MUD are occurring at other centers and to the potential causesCopyright © 2023 American Society for Transplantation and Cellular Therapy

Interferon-induced transmembrane protein 3 (IFITM3) limits lethality of SARS-CoV-2 in mice.

Interferon-induced transmembrane protein 3 (IFITM3) is an antiviral protein that alters cell membranes to block fusion of viruses. Conflicting reports identified opposing effects of IFITM3 on SARS-CoV-2 infection of cells, and its impact on viral pathogenesis in vivo remains unclear. Here, we show that IFITM3 knockout (KO) mice infected with SARS-CoV-2 experience extreme weight loss and lethality compared to mild infection in wild-type (WT) mice. KO mice have higher lung viral titers and increases in inflammatory cytokine levels, immune cell infiltration, and histopathology. Mechanistically, we observe disseminated viral antigen staining throughout the lung and pulmonary vasculature in KO mice, as well as increased heart infection, indicating that IFITM3 constrains dissemination of SARS-CoV-2. Global transcriptomic analysis of infected lungs shows upregulation of gene signatures associated with interferons, inflammation, and angiogenesis in KO versus WT animals, highlighting changes in lung gene expression programs that precede severe lung pathology and fatality. Our results establish IFITM3 KO mice as a new animal model for studying severe SARS-CoV-2 infection and overall demonstrate that IFITM3 is protective in SARS-CoV-2 infections in vivo.

Neuropathological features of SARS-CoV-2 delta and omicron variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is continually evolving resulting in variants with increased transmissibility, more severe disease, reduced effectiveness of treatments or vaccines, or diagnostic detection failure. The SARS-CoV-2 Delta variant (B.1.617.2 and AY lineages) was the dominant circulating strain in the United States from July to mid-December 2021, followed by the Omicron variant (B.1.1.529 and BA lineages). Coronavirus disease 2019 (COVID-19) has been associated with neurological sequelae including loss of taste/smell, headache, encephalopathy, and stroke, yet little is known about the impact of viral strain on neuropathogenesis. Detailed postmortem brain evaluations were performed for 22 patients from Massachusetts, including 12 who died following infection with Delta variant and 5 with Omicron variant, compared to 5 patients who died earlier in the pandemic. Diffuse hypoxic injury, occasional microinfarcts and hemorrhage, perivascular fibrinogen, and rare lymphocytes were observed across the 3 groups. SARS-CoV-2 protein and RNA were not detected in any brain samples by immunohistochemistry, in situ hybridization, or real-time quantitative PCR. These results, although preliminary, demonstrate that, among a subset of severely ill patients, similar neuropathological features are present in Delta, Omicron, and non-Delta/non-Omicron variant patients, suggesting that SARS-CoV-2 variants are likely to affect the brain by common neuropathogenic mechanisms.

Distinguishing SARS-CoV-2 persistence and reinfection: A retrospective cohort study.

BACKGROUND: SARS-CoV-2 reinfection is poorly understood, partly because few studies have systematically applied genomic analysis to distinguish reinfection from persistent RNA detection related to initial infection. We aimed to evaluate the characteristics of SARS-CoV-2 reinfection and persistent RNA detection using independent genomic, clinical, and laboratory assessments. METHODS: All individuals at a large academic medical center who underwent a SARS-CoV-2 nucleic acid amplification test (NAAT) ≥ 45 days after an initial positive test, with both tests between March 14th and December 30th, 2020, were analyzed for potential reinfection. Inclusion criteria required having ≥2 positive NAATs collected ≥45 days apart with a cycle threshold (Ct) value <35 at repeat testing. For each included subject, likelihood of reinfection was assessed by viral genomic analysis of all available specimens with a Ct value <35, structured Ct trajectory criteria, and case-by-case review by infectious diseases physicians. RESULTS: Among 1,569 individuals with repeat SARS-CoV-2 testing ≥45 days after an initial positive NAAT, 65 (4%) met cohort inclusion criteria. Viral genomic analysis characterized mutations present, and was successful for 14/65 (22%) subjects. Six subjects had genomically-supported reinfection and eight subjects had genomically-supported persistent RNA detection. Compared to viral genomic analysis, clinical and laboratory assessments correctly distinguished reinfection from persistent RNA detection in 12/14 (86%) subjects but missed 2/6 (33%) genomically-supported reinfections. CONCLUSION: Despite good overall concordance with viral genomic analysis, clinical and Ct value-based assessments failed to identify 33% of genomically-supported reinfections. Scaling-up genomic analysis for clinical use would improve detection of SARS-CoV-2 reinfections.

Duration of Device-Based Fever Prevention after Cardiac Arrest.

BACKGROUND: Guidelines recommend active fever prevention for 72 hours after cardiac arrest. Data from randomized clinical trials of this intervention have been lacking. METHODS: We randomly assigned comatose patients who had been resuscitated after an out-of-hospital cardiac arrest of presumed cardiac cause to device-based temperature control targeting 36°C for 24 hours followed by targeting of 37°C for either 12 or 48 hours (for total intervention times of 36 and 72 hours, respectively) or until the patient regained consciousness. The primary outcome was a composite of death from any cause or hospital discharge with a Cerebral Performance Category of 3 or 4 (range, 1 to 5, with higher scores indicating more severe disability; a category of 3 or 4 indicates severe cerebral disability or coma) within 90 days after randomization. Secondary outcomes included death from any cause and the Montreal Cognitive Assessment score (range, 0 to 30, with higher scores indicating better cognitive ability) at 3 months. RESULTS: A total of 393 patients were randomly assigned to temperature control for 36 hours, and 396 patients were assigned to temperature control for 72 hours. At 90 days after randomization, a primary end-point event had occurred in 127 of 393 patients (32.3%) in the 36-hour group and in 133 of 396 patients (33.6%) in the 72-hour group (hazard ratio, 0.99; 95% confidence interval, 0.77 to 1.26; P = 0.70) and mortality was 29.5% in the 36-hour group and 30.3% in the 72-hour group. At 3 months, the median Montreal Cognitive Assessment score was 26 (interquartile range, 24 to 29) and 27 (interquartile range, 24 to 28), respectively. There was no significant between-group difference in the incidence of adverse events. CONCLUSIONS: Active device-based fever prevention for 36 or 72 hours after cardiac arrest did not result in significantly different percentages of patients dying or having severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Subcutaneous delivery of an antibody against SARS-CoV-2 from a supramolecular hydrogel depot.

Prolonged maintenance of therapeutically-relevant levels of broadly neutralizing antibodies (bnAbs) is necessary to enable passive immunization against infectious disease. Unfortunately, protection only lasts for as long as these bnAbs remain present at a sufficiently high concentration in the body. Poor pharmacokinetics and burdensome administration are two challenges that need to be addressed in order to make pre- and post-exposure prophylaxis with bnAbs feasible and effective. In this work, we develop a supramolecular hydrogel as an injectable, subcutaneous depot to encapsulate and deliver antibody drug cargo. This polymer-nanoparticle (PNP) hydrogel exhibits shear-thinning and self-healing properties that are required for an injectable drug delivery vehicle. In vitro drug release assays and diffusion measurements indicate that the PNP hydrogels prevent burst release and slow the release of encapsulated antibodies. Delivery of bnAbs against SARS-CoV-2 from PNP hydrogels is compared to standard routes of administration in a preclinical mouse model. We develop a multi-compartment model to understand the ability of these subcutaneous depot materials to modulate the pharmacokinetics of released antibodies; the model is extrapolated to explore the requirements needed for novel materials to successfully deliver relevant antibody therapeutics with different pharmacokinetic characteristics.

Characterization of virologic rebound following nirmatrelvir-ritonavir treatment for COVID-19.

We enrolled seven individuals with recurrent symptoms or antigen test conversion following nirmatrelvir-ritonavir treatment. High viral loads (median 6.1 log10 copies/mL) were detected after rebound for a median of 17 days after initial diagnosis. Three had culturable virus for up to 16 days after initial diagnosis. No known resistance-associated mutations were identified.

Is Multi System Inflammatory Syndrome Secondary to Covid (Mis-C) Same as Sepsis Associated Secondary Hlh?

Purpose: COVID 19 infection in children is generally mild,however some of them develop an unique immunological phenomenon called MIS-C(multi-system inflammatory syndrome, which is a hyperimmune state resulting in vasculitis,mycarditis and end organ damage.We compared immune status of MIS-C with another viral infection triggered hyperinflammtory state;sepsis hemophagocyticlymphohistiocytosis (SHLH) to understand the pathogenses of this novel clinical syndrome Methods: We included patients with MIS-C, SHLH and viral sepsis(S) Blood samples were collected after written informed consent, utilizing protocols approved by our institution. We evaluated differential leukocyte counts, soluble markers of T cell and macrophage activation (sIL-2R, sCD163 and Ferritin) in plasma and did immunophenotyping of T cells and monocytes on cryopreserved peripheral blood mononuclear cells Results: Total of 62 children (MIS-C 27, Sepsis 27 &SHLH 8) were included with age ranging from 1 to 16 years. Total leukocyte counts did not differ across the groups. MISC had higher neutrophil counts as compared to SHLH and sepsis.(Median cu/mm : MIS-C -10062 SHLH-4434, S- 3138). Monocyte(M)and lymphocyte (L)numbers were comparable with SHLH but lesser than sepsis(Median M/L cummMISC- 390/1488, SHLH-252/1565, S-795/2841). Plasma levels of sIL-2R in MIS-C and SHLH were similarly elevated as opposed to sepsis(Median pg/ml MIS-C- 17824, SHLH- 25702, S - 3653). sCD163 levels was elevated highest in SHLH, followed by MIS-C and Sepsis (Median ng/ml SHLH- 2.18, MIS-C 0-96,S- 0.25). Similar trend was seen in proportions of activated T cells (HLADR+CD38+) across the groups (Median % SHLH 32.5, MIS-C- 4.31, S 1.14). Median CD4:CD8 in MIS-C (2.5) is comparable to sepsis (1.2) but significantly higher than SHLH (0.75) There was no difference inmonocyte activation Conclusion(s):MIS-C is a hyperimmune state but the immune profile has features overlapping with SHLH and sepsis. It is a different hyperimmune syndrome as compared to SHLH and needs more mechanistic studies.

Human Well-Being and Pandemic Crisis: Implications for Social Work Practice from Kerala Experience

Nipah virus, the consecutive 2018 and 2019 floods, the internal social, economic and political struggles have had a significant impact on the lives of people in Kerala, India. While the state of Kerala was trying to get back to some form of stability, Covid-19 slams into, in an unprecedented way, drastically disrupting the lives of many. It has shaken the interconnectedness and interdependence of families and placed communities in a state of fear, anxiety and uncertainty. This article is about the vulnerabilities, experiences, voices and untold stories of courage and resilience among people in Kerala. Authors present a reflective analysis of the multidimensional impact of Covid-19 on the ordinary lives of the people of Kerala. The deleterious impact of the Covid-19 pandemic on the entire humanity reckons the attention of governments, economists, educators, social scientists, medical and allied professionals, including social workers, to make concerted efforts to preserve and promote human well-being. Taking into consideration the structural inequalities in society, the present paper utilises a critical social work theoretical lens to analyse how it has impacted the well-being of people, especially the marginalised and vulnerable communities in Kerala. © 2020 Jacab et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Inferring selection effects in SARS-CoV-2 with Bayesian Viral Allele Selection.

The global effort to sequence millions of SARS-CoV-2 genomes has provided an unprecedented view of viral evolution. Characterizing how selection acts on SARS-CoV-2 is critical to developing effective, long-lasting vaccines and other treatments, but the scale and complexity of genomic surveillance data make rigorous analysis challenging. To meet this challenge, we develop Bayesian Viral Allele Selection (BVAS), a principled and scalable probabilistic method for inferring the genetic determinants of differential viral fitness and the relative growth rates of viral lineages, including newly emergent lineages. After demonstrating the accuracy and efficacy of our method through simulation, we apply BVAS to 6.9 million SARS-CoV-2 genomes. We identify numerous mutations that increase fitness, including previously identified mutations in the SARS-CoV-2 Spike and Nucleocapsid proteins, as well as mutations in non-structural proteins whose contribution to fitness is less well characterized. In addition, we extend our baseline model to identify mutations whose fitness exhibits strong dependence on vaccination status as well as pairwise interaction effects, i.e. epistasis. Strikingly, both these analyses point to the pivotal role played by the N501 residue in the Spike protein. Our method, which couples Bayesian variable selection with a diffusion approximation in allele frequency space, lays a foundation for identifying fitness-associated mutations under the assumption that most alleles are neutral.

SARS-CoV-2 IgG Antibody Levels in Women with IBD Vaccinated during Pregnancy.

INTRODUCTION: Regulatory agencies supported vaccination of pregnant women with SARS-CoV-2 mRNA vaccines, including patients with IBD. No data exist regarding these vaccines in IBD during pregnancy. AIM: To assess the serologic response to two doses of the mRNA SARS-CoV-2 BNT162b2 vaccine in pregnant women with IBD vaccinated during pregnancy, compared to that of pregnant women without IBD, and non-pregnant women with IBD. METHODS: Anti-spike antibody levels were assessed in all women and in cord blood of consenting women. RESULTS: From December 2020 to December 2021, 139 women were assessed: pregnant with IBD-36, pregnant without IBD-61, and not pregnant with IBD-42. Antibodies were assessed in cords of two and nine newborns of women with and without IBD, respectively. Mean gestational ages at administration of the second vaccine doses were 22.0 weeks in IBD and 23.2 weeks in non-IBD, respectively. Mean (SD) duration from the second vaccine dose to serology analysis in pregnant women with IBD, without IBD, and in non-pregnant women with IBD was 10.6 (4.9), 16.4 (6.3), and 4.3 (1.0) weeks, respectively. All women mounted a serologic response. In multivariable analysis, no correlation was found between the specific group and antibody levels. In both pregnancy groups, an inverse correlation between antibody levels and the interval from the second vaccine dose was demonstrated. Cord blood antibody levels exceeded maternal levels in women with and without IBD. CONCLUSION: All patients with IBD mounted a serologic response. The interval between vaccine administration to serology assessment was the most important factor determining antibody levels. A third vaccine dose should be considered in pregnant women with IBD vaccinated at early stages of pregnancy.

Heterotopic Ossification after a Prolonged Course of COVID-19: A Case Report and Review of the Literature

We report the case of a 20-year-old male who developed severe HO of the left hip secondary to a prolonged course of COVID-19 pneumonia. Upon extubation, he was found to have debilitating left hip pain and significant functional deficits with regard to his range of motion and functional status. There are numerous known causes of heterotopic ossification (HO), including trauma, surgery, and traumatic brain or spinal cord injuries. An increased incidence of HO has also been reported in patients who undergo prolonged intubation. While the COVID-19 virus has many known respiratory and medical complications, it has also resulted in unforeseen complications that present long-term challenges for patients. When treating patients with coronavirus, physicians should be aware of HO as a possible complication and consider it as a cause of musculoskeletal pain.

Vaccine breakthrough infection leads to distinct profiles of neutralizing antibody responses by SARS-CoV-2 variant.

Protective immunity against SARS-CoV-2 infection after COVID-19 vaccination may differ by variant. We enrolled vaccinated (n = 39) and unvaccinated (n = 11) individuals with acute, symptomatic SARS-CoV-2 Delta or Omicron infection and performed SARS-CoV-2 viral load quantification, whole-genome sequencing, and variant-specific antibody characterization at the time of acute illness and convalescence. Viral load at the time of infection was inversely correlated with antibody binding and neutralizing antibody responses. Across all variants tested, convalescent neutralization titers in unvaccinated individuals were markedly lower than in vaccinated individuals. Increases in antibody titers and neutralizing activity occurred at convalescence in a variant-specific manner. For example, among individuals infected with the Delta variant, neutralizing antibody responses were weakest against BA.2, whereas infection with Omicron BA.1 variant generated a broader response against all tested variants, including BA.2.

First-generation antipsychotics use and reduced risk of pneumonia—Clinical implications in SARS-CoV2 treatment: A systematic review and meta-analysis of observational studies

The use of antipsychotics (AP) has been linked to nearly 60% increase in the incidence of pneumonia. The study purposes to devise safest treatment regimens for psychiatric patients with underlying respiratory comorbidities. A systematic literature search was conducted. A total of 41 studies were evaluated, which included 33 articles for metaanalysis. The quality of retrieved articles was screened by reviewing independently. The risk of bias in each study was assessed using the Newcastle–Ottawa Scale. Inter-rater agreement calculation was performed using Rayyan QCRI. Statistical analysis was performed using R 4.0.3. The meta-analysis conducted revealed that the risk of pneumonia (OR = 1.66;95% CI = 1.64–1.68) and respiratory failure (OR = 1.79;95% CI = 1.61–2.00) were higher in psychotropic users compared to nonusers. Pneumonia risk was higher in second-generation antipsychotic users (OR = 1.12;95% CI = 1.01–1.25) compared to other antipsychotic users. However, no association was found between firstgeneration antipsychotics and pneumonia compared to other psychotropic exposure (OR = 0.93;95% CI = 0.86–0.99). Chlorpromazine, sulpiride, and aripiprazole were found to be statistically safer compared to other AP. AP should be of appropriate choice in patients with SARS-CoV-2 infection, recurrent pneumonia history or those with opportunistic infections. © 2022 Abhirami Eby et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

Anti-TNFα Treatment Impairs Long-Term Immune Responses to COVID-19 mRNA Vaccine in Patients with Inflammatory Bowel Diseases.

Patients with inflammatory bowel disease (IBD) treated with anti-tumor-necrosis factor-alpha (TNFα) exhibited lower serologic responses one-month following the second dose of the COVID-19 BNT162b2 vaccine compared to those not treated with anti-TNFα (non-anti-TNFα) or to healthy controls (HCs). We comprehensively analyzed long-term humoral responses, including anti-spike (S) antibodies, serum inhibition, neutralization, cross-reactivity and circulating B cell six months post BNT162b2, in patients with IBD stratified by therapy compared to HCs. Subjects enrolled in a prospective, controlled, multi-center Israeli study received two BNT162b2 doses. Anti-S levels, functional activity, specific B cells, antigen cross-reactivity, anti-nucleocapsid levels, adverse events and IBD disease score were detected longitudinally. In total, 240 subjects, 151 with IBD (94 not treated with anti-TNFα and 57 treated with anti-TNFα) and 89 HCs participated. Six months after vaccination, patients with IBD treated with anti-TNFα had significantly impaired BNT162b2 responses, specifically, more seronegativity, decreased specific circulating B cells and cross-reactivity compared to patients untreated with anti-TNFα. Importantly, all seronegative subjects were patients with IBD; of those, >90% were treated with anti-TNFα. Finally, IBD activity was unaffected by BNT162b2. Altogether these data support the earlier booster dose administration in these patients.

Hematopoietic Stem/Progenitor Cells and Engineering: 20-YEAR HEMATOPOIETIC PROGENITOR CELL STABILITY – THE MAYO CLINIC EXPERIENCE

Background & Aim: Hematopoietic progenitor cells (HPCs) are infused for hematopoietic reconstitution in the setting of malignancy and inherited or acquired hematological deficiencies. Given the global COVID-19 pandemic, the recommendation was made to cryopreserve all allogeneic HPCs to protect recipients by allowing for subclinical cases of infection to present prior to infusion. As such, consideration of HPC stability programs (SP) and their rigor has risen. The goal of a SP is to prove the rigor of a transplant program’s cryopreservation and storage standard operating procedures so that sufficient HPC viability and potency are maintained for engraftment. SPs are also required by accreditation agencies such as AABB and FACT. Many HPC SP have validated product expirations out to 10 years. Here we share our SP to 20 years with ongoing validation for 30-year expiration. Methods, Results & Conclusion: Program Design: Current testing frequency of our SP is within the first year, and then at three-year intervals (3, 6, 9, 12, 15, 19, 21). Our rolling SP includes 2 additional (Figure Presented) Fig. 1.Current vs proposed HPC product testing and cryopreseveration schema. samples tested at 0, 5, & 9 years, then at 3-year intervals (12, 15, 19, 21, 24, 27, 30). SP samples are collected from donors requiring additional days to reach their goal but are in excess at the conclusion of collection (e.g., Day 1 collection 4.5e6 CD34+ cells/Kg, goal 5e6 CD34+ cells/ Kg). Samples are collected on a quarterly basis with ten 1mL cryovials being drawn (Figure 1). CD3+ and CD34+ viabilities are tested after cryopreservation with an acceptable threshold set at ≥75% for both. Conclusion: We are validating our SP up to 20 years with intention to validate to 30 years. Thus far, our SP reveals product age has no to low correlation with engraftment, suggesting maintenance of potency over time in a cryopreservative of 10% DMSO, 10% plasma, and 30% PlasmaLyte-A with a final cell concentration of ≤3×108 NC/mL (Figure 2). Successful engraftment has been seen in all recipients. Transplant programs should modify testing frequency, acceptance criteria, and product expiration to meet individual need while working towards standardization in the field. Given the frequency of DLIs and 2nd/3rd transplants at the Mayo Clinic, a 30-year SP reflects the need of our transplant program.(Figure Presented)Fig. 2 . ANC and platelet engraftment dates for ≥10-year-old HPC products