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