Simple prediction of COVID-19 convalescent plasma with high levels of neutralization antibodies (preprint)

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 the respective results >6000 AU/ml SARS-CoV-2 IgG had an 80% probability of attaining high 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 efficiently predicting CCP donors with high titer NAbs.

ABO blood group type does not influence the level of SARS-CoV-2 antibody response in convalescent plasma donors (preprint)

The association of ABO blood group types with the COVID-19 disease has been confirmed by several studies, with the blood group A-type patients being more susceptible and prone to more severe clinical course of disease. Similarly, some authors explored the association of ABO-types and the levels of anti-SARS-CoV-2 antibodies in convalescents. The recent reports mostly support a theory that non-O blood group convalescents present with higher levels of anti-SARS-CoV-2 antibodies. Since these findings were based on small convalescent cohorts, we quantified the anti-SARS-CoV-2 antibodiy levels in four larger cohorts of total 3185 convalescent plasma donors with three commercial serological tests and one standard neutralizing antibody test. The majority of donors had undergone a mild form of disease and the median time of sampling was 66 days after the onset of COVID-19 symptoms. None of the antibody quantitation methods showed an association of the ABO blood group types with the level of anti-SARS-CoV-2 antibodies. The same result is evident in the group of vaccinated individuals (n=370) as well as in the groups stratified into three post-COVID-19 periods (0-60, 60-120, and 120-180 days). In conclusion we can state that the ABO blood group type does not influence the level of SARS-CoV-2 antibody response in COVID-19 convalescent plasma donors.