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Introduction Seroprevalence surveys can estimate the cumulative incidence of SARS-CoV-2 infection in a symptom-independent manner, offering valuable data, including herd immunity, that can inform national and local public health policies. To our knowledge, there have been no large studies reporting seroprevalence in healthcare workers (HCWs) in the state of Arkansas. The objective of this study is to measure SARS-CoV-2 seroprevalence in HCWs in a large tertiary-care healthcare system prior to vaccine availability. Methods The Central Arkansas Veterans Healthcare System offered SARS-CoV-2 antibody testing prior to the widespread availability of vaccines. After Central Arkansas Veterans Healthcare System institutional review board (IRB) approval had been obtained, a retrospective chart review was used to identify all Central Arkansas Veterans Healthcare System HCWs who had undergone SARS-CoV-2 antibody testing from July 1, 2020, to September 30, 2020. Descriptive analysis was performed using Microsoft Excel (Microsoft Corporation, Redmond, Washington, United States). Correlation and regression tests were performed using SAS 9.4 software (SAS Institute Inc., Cary, NC). Results Over the study interval, 170 healthcare personnel had undergone SARS-CoV-2 anti-spike IgG antibody testing. Thirty-seven (21.8%) had positive antibody results. The 37 individuals were mostly women (94.5%), and the average age of the group was 47 years (range 29-69 years). The median antibody titers for those testing positive for antibodies were 10.8 units (range 1.1-58.5). Of the 37 people, 32 had a history of COVID-19 infection proven by reverse transcriptase polymerase chain reaction (RT-PCR). Conclusion Serologic testing is feasible for healthcare workers to document an immune response to a prior infection. In this study of HCWs, the rate of positivity among those tested was 21.8%. Data that do not incorporate the cohort of patients with prior infections will underestimate the impact of prior infections on herd immunity statistics and may misinform public policy., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Joshi et al.)

In children with sickle cell disease (SCD), primary and secondary prevention of strokes require indefinite regular blood transfusion therapy. The risks associated with repeated transfusions include alloimmunization and increased donor exposure. The Charles Drew Program is a directed blood donor program designed to lower donor exposure, decreasing the associated complications of transfusion; however, no evidence exists demonstrating the magnitude of the benefit to the recipient. Further, the use of extended red blood cell (RBC) antigen matching for C, E, and K has been well documented in a clinical trial setting but not extensively evaluated in a standard care setting. The goal of this study is to assess the effectiveness in reducing alloimmunization when matching for C, E, and K and the magnitude of the decrease in donor exposure in a directed blood donor program. The rate of alloimmunization and reduction of donor exposure were determined during the course of 1 year in a cohort of children with SCD who received regular directed donor blood transfusions. A total of 24 recipients were in the program, 16 females and 8 males, 4 to 20 years of age. During 2008, alloimmunization was 0 percent and donor exposure was reduced by 20 percent, compared with usual care. Extended RBC antigen matching has the same benefit as in a clinical trial setting for patients with SCD receiving blood transfusion therapy. Despite significant effort, we only achieved a modest decrease in donor exposure and cannot determine the immediate benefit of a directed blood donor program.

Background: Washed or volume-reduced platelets (PLTs) are occasionally requested for patients with a history of allergic or anaphylactic transfusion reactions. However, conclusive data are not available as to which method is more suitable., Study Design and Methods: A direct comparison of saline-washed and volume-reduced PLTs was performed by splitting 11 units of 6-day-old apheresis PLT units. PLT activation, aggregation, plasma protein, and PLT count were determined before and after each procedure. To assess whether washing using neutral, calcium-free Ringer's acetate (NRA) would better preserve PLT function, 8 additional units of apheresis PLTs were split and were washed in saline or NRA., Results: Saline washing resulted in significantly increased number of activated, P-selectin-expressing PLTs compared to volume reduction (24.2% vs. 10.3%, p = 0.001). Aggregation was also significantly reduced (-40.6% vs. -0.8%, p = 0.004). Plasma protein removal was significantly better for saline-washed than volume-reduced PLTs (96% vs. 51.1%, p < 0.001). PLT recovery was not significantly different for saline-washed versus volume-reduced PLTs (70.5% vs. 80.7%, p = 0.079). There was no difference between washing in saline or NRA with regard to PLT activation and loss of aggregation., Conclusions: PLT washing with saline or NRA significantly increases PLT activation and decreases PLT aggregability. On the other hand, volume reduction does not adequately remove plasma proteins. Therefore, PLT washing should be reserved for patients with a history of severe allergic or anaphylactic transfusion reactions. We suggest that fresher PLTs be selected to improve the functionality of washed PLTs., (© 2010 American Association of Blood Banks.)

Background: Use of unrelated cord blood transplantation (UCBT) is increasing, yet high rates of mortality secondary to infection remain a problem. We investigated the utility of using umbilical cord blood (UCB) as a model to study a naive cell population challenged by Mycobacterium tuberculosis., Methods: Mononuclear cells were isolated from nine UCB samples and infected with each of four distinct strains of M. tuberculosis. The isolates used were two highly transmissible clinical strains, the virulent laboratory strain H37Rv and a unique strain isolated from only one case (i.e. non-virulent). CFU were assessed at 3 h post-infection (day 0) and at day 7 to generate growth curves. Viability of the mononuclear cells was assessed prior to infection, 3 h post-infection and at days 3, 5 and 7 post-infection. IFN-gamma and TNF-alpha levels were determined at 24 h post-infection., Results: All three of the virulent strains demonstrated rapid growth in UCB cells that was significantly faster than the growth rate observed for the non-virulent unique isolate. There was no significant decrease in UCB cell viability after the 7-day incubation period regardless of infecting isolate. UCB cells secreted IFN-gamma in response to infection, with no significant difference related to infection with different isolates. However, there was a significant increase in the amount of TNF-alpha elicited following infection with the non-virulent isolate compared with the virulent isolates., Discussion: These results show that UCB can be used as a model to study infection, hopefully leading to new therapies for neonates and UCBT recipients.