COVID-19 Antibody Testing in Healthcare Workers in Arkansas.

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.

Red blood cell transfusion: impact of an education program and a clinical guideline on transfusion practice.

BACKGROUND: Red blood cell (RBC) transfusion guidelines have been developed by professional societies. These guidelines recommend a restrictive RBC transfusion practice for most clinical populations. Despite the consistency of guidelines and limited evidence for RBC transfusion efficacy, there is variability in RBC transfusion practice. METHODS: A program was initiated in a tertiary medical center to align RBC transfusion practice with best-practice RBC transfusion guidelines. The program included an educational program, followed after 6 months by RBC transfusion decision support that included the approval of a best-practice RBC transfusion guideline by the hospital medical board and an RBC transfusion order form that included the guideline recommendations. RBC transfusion practice was followed over an 18-month period and compared with transfusion practice over the prior 18 months. The primary outcome variables were adult inpatient RBC units transfused, RBC units per admission, and RBC units per 100 patient-days. RESULTS: The mean RBC units transfused decreased with initiation of each component of the program: from 923 ± 68 units to 852 ± 40 (P = 0.025) with education and further to 690 ± 52 (P < 0.0001) with the RBC transfusion decision support. Similarly, RBC transfusions per 100 patient-days fell from 10.56 ± 0.80 to 9.69 ± 0.49 (P = 0.02) and to 7.68 ± 0.63 (P = 0.0001) during the 3 time periods. CONCLUSION: An education program coupled with institutional adoption of a best-practice RBC transfusion guideline and RBC transfusion order set resulted in a reduction in total RBC units transfused.

A comparison of washed and volume-reduced platelets with respect to platelet activation, aggregation, and plasma protein removal.

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.

Viability and engraftment of hematopoietic progenitor cells after long-term cryopreservation: effect of diagnosis and percentage dimethyl sulfoxide concentration.

BACKGROUND AIMS: We carried out a retrospective analysis of viability by diagnosis and dimethyl sulfoxide (DMSO) concentration in patients who had undergone autologous transplants using hematopoietic progenitor cells (HPC) after long-term storage (up to 17.8 years). METHODS: Viability was tested using flow cytometry for HPC that were harvested and preserved using a controlled rate freezer and 5% or 10% DMSO with human serum albumin, then stored in liquid nitrogen. Data from 262 samples were analyzed (249 myeloma patients and 13 other diagnoses): 100 consecutively thawed samples with a storage time of <1 year (all 10% DMSO), 50 consecutive samples stored for 1-4.9 years (10% DMSO), 50 samples stored for 5-9 years (5% DMSO) and all samples stored and used for transplant after >9 years (60 samples, 5% DMSO; two samples, 10% DMSO). RESULTS: No statistically significant difference in viability between the 5% DMSO and 10% DMSO groups was observed (P = 0.08), so the 1-4.9 years and 5-9 years were combined and the three groups (<1 year, 1-9 years and >9 years) were compared using an anova test. There was no difference in viability based on cryostorage period (P = 0.23) or between myeloma and other diagnoses (P = 0.45). No difference was seen in time to White blood cell (WBC) engraftment (P = 0.10) or to platelet engraftment between groups (P = 0.52). CONCLUSIONS: These data suggest that long-term storage in 5% DMSO and human serum albumin is safe.

A correlation between growth rate, apoptosis, and tumor necrosis factor-α in umbilical cord blood cells infected with two strains of Mycobacterium tuberculosis.

BACKGROUND: Using umbilical cord blood (UCB) cells, it was demonstrated that three virulent isolates, two highly transmissible clinical isolates and the virulent laboratory strain, demonstrated rapid growth in the UCB cells, which was significantly faster than the growth rate observed for a unique isolate. There was also a significant increase in the amount of tumor necrosis factor (TNF)-a elicited from the UCB cells after infection with the unique isolate compared to the hypervirulent isolates. This study investigated whether neutralization or addition of TNF-a within this system would alter growth rates and apoptosis. STUDY DESIGN AND METHODS: Ten UCB samples were obtained for these experiments and adherent cells were isolated. Two clinical isolates, one virulent and one unique, were used. Colony-forming units were assessed at 3 hours postinfection (Day 0) and on Day 7 to generate growth ratios. TNF-a antibody or exogenous TNF-a was added after the 3-hour incubation period. Viability of the UCB cells was assessed. Apoptosis was measured using terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling staining. RESULTS: There was no significant difference in the growth ratio for the virulent strain regardless of the presence of TNF-a antibody. There was a significant increase for the nonvirulent strain after the addition of antibody. There was an increase in viability for the UCB cells in the presence of antibody, suggesting a decrease in TNF-a­dependent apoptosis. Addition of exogenous TNF-a to the UCB cells after infection with the virulent strain decreased the growth ratio with a significant increase in apoptosis. CONCLUSIONS: The TNF-a response of the UCB cells is related to the infecting strain and the intracellular growth of the strain of Mycobacterium tuberculosis is not directly controlled by the level of TNF-a. This cytokine is at the start of a powerful cascade of transcription factors with numerous pleiotropic effects; consequently abrogating/enhancing a single direct outcome was difficult, with only slight alterations in growth.