Simple prediction of COVID-19 convalescent plasma units with high levels of neutralization antibodies.

BACKGROUND: Hyperimmune convalescent COVID-19 plasma (CCP) containing anti-SARS-CoV-2 neutralizing antibodies (NAbs) was proposed as a therapeutic option for patients early in the new coronavirus disease pandemic. The efficacy of this therapy depends on the quantity of neutralizing antibodies (NAbs) in the CCP units, with titers ≥ 1:160 being recommended. The standard neutralizing tests (NTs) used for determining appropriate CCP donors are technically demanding and expensive and take several days. We explored whether they could be replaced by high-throughput serology tests and a set of available clinical data. METHODS: Our study included 1302 CCP donors after PCR-confirmed COVID-19 infection. To predict donors with high NAb titers, we built four (4) multiple logistic regression models evaluating the relationships of demographic data, COVID-19 symptoms, results of various serological testing, the period between disease and donation, and COVID-19 vaccination status. RESULTS: The analysis of the four models showed that the chemiluminescent microparticle assay (CMIA) for the quantitative determination of IgG Abs to the RBD of the S1 subunit of the SARS-CoV-2 spike protein was enough to predict the CCP units with a high NAb titer. CCP donors with respective results > 850 BAU/ml SARS-CoV-2 IgG had a high probability of attaining sufficient NAb titers. Including additional variables such as donor demographics, clinical symptoms, or time of donation into a particular predictive model did not significantly increase its sensitivity and specificity. CONCLUSION: A simple quantitative serological determination of anti-SARS-CoV-2 antibodies alone is satisfactory for recruiting CCP donors with high titer NAbs.

ABO blood group does not influence the level of anti-SARS-CoV-2 antibodies in convalescent plasma donors.

BACKGROUND: The association of the ABO blood group with COVID-19 disease has been confirmed by several studies, with the blood group A patients being more susceptible and prone to a more severe clinical course of the disease. Additionally, several authors also addressed the association of ABO-types and the levels of anti-SARS-CoV-2 antibodies in convalescents, mostly supporting a theory that the non-O blood group convalescents present with higher levels of anti-SARS-CoV-2 antibodies. STUDY DESIGN AND METHODS: Since previous findings were based on small convalescent cohorts, we quantified the anti-SARS-CoV-2 antibody levels in a total of 3187 convalescent plasma donors with three commercial serological and one standard neutralizing antibody test. The majority of donors had undergone a mild form of the disease and the median time of sampling was 66 days after diagnosis. RESULTS: None of the antibody quantitation results showed any significant association with the ABO blood group types. The same result was evident in the subgroup of vaccinated individuals (n = 370) and the subgroups when stratified according to post-COVID-19 periods (0-60, 60-120, and 120-180 days). CONCLUSION: In conclusion, we found no evidence to confirm that the ABO blood group types influence the level of SARS-CoV-2 antibody response in COVID-19 convalescent plasma donors.