key: cord-0954365-4wk3yzex
authors: Franchini, Mario; Mengoli, Carlo; Ballotari, Alessia; Glingani, Claudia
title: Correlation between ABO blood group and neutralizing anti-SARS-CoV-2 antibody titers in convalescent plasma donations
date: 2021-10-12
journal: Transfus Clin Biol
DOI: 10.1016/j.tracli.2021.10.002
sha: cb30175ec424d8a8a2ad85115612e911700e7a21
doc_id: 954365
cord_uid: 4wk3yzex

nan

Many efforts have been made during the last 18 months to identify factors associated with SARS-CoV-2 antibody response in COVID-19 convalescent plasma (CCP) donors, with older age, male sex and disease severity having been identified as the main predictors (1, 2) . Although the association between ABO blood type and susceptibility to COVID-19 is well known and studied

(3), with individuals having O blood type being less prone to infection, there is more uncertainty regarding ABO blood group-driven SARS-CoV-2 antibody response. Hayes and colleagues (4) recently observed that blood group O CCP donors have significantly lower levels of SARS-CoV-2 IgG antibodies than do donors with other blood groups. Antibody levels were measured using a semi-quantitative chemiluminescent immunoassay as a surrogate for the traditional plaque reduction neutralization test (PRNT). To assess their findings, we studied the correlation between 496 consecutive CCP donations, given at the Transfusion Center of Mantova city hospital, and the SARS-CoV-2 neutralizing antibody titer, measured using the gold-standard PRNT (performed at the Molecular Virology Unit of the University Hospital of Pavia and based on the determination of the in vivo cytopathic effect, as previously described) (5).

The ABO blood group distribution among the study population (394 CCP donors) was the (table 1b) . Again, however, the greatest difference was between O and AB blood groups (-52.98). Interestingly, the proportion of donations reaching a high neutralizing titer (defined as ≥ 80) was lower in O blood type donors than in non-O blood type donors, among whom we observed a progressive increase from A to B and AB blood groups, with CCP AB donations comprising the highest proportion of those with a neutralizing titer ≥ 80 (table   2 ).

In conclusion, although the ABO system-related effect was weaker, the results of our study are consistent with those of Hayes and colleagues (4) and support the preferential collection of CCP 

Clinical predictors of SARS-CoV-2 neutralizing antibody titers in COVID-19 convalescents: implications for convalescent plasma donor recruitment