Transfusion. 2021 Mar 30. doi: 10.1111/trf.16392. Online ahead of print.
BACKGROUND: Infection with SARS-CoV-2 may be life-threatening and specific antiviral drugs are currently not available. However, first studies indicated that convalescent plasma treatment might improve the clinical outcome of COVID-19 patients.
STUDY DESIGN AND METHODS: In the current study, we investigated the efficacy of convalescent plasma treatment in eight COVID-19 patients. All patients were critically ill and 7/8 SARS-CoV-2 RNA positive when starting treatment. SARS-CoV-2 specific antibodies were determined by an ELISA detecting IgG antibodies against the S1 protein (Euroimmun) and the neutralizing titers were determined with a cell-culture based neutralization assay. Plasma treatment started between 4 and 23 days after the onset of symptoms. The patients were usually treated by three plasma units, each containing 200-280 ml, which was applied at day 1, 3 and 5.
RESULTS: Donor sera had on average lower IgG antibody ratios and neutralizing titers than the COVID-19 patients before the onset of treatment (median ratio of 5.8 and neutralizing titer of 1:320 vs. 7.5 and 1:640, respectively). Nevertheless, we observed an increase of antibody ratios in seven and of neutralizing titers in five patients after treatment; which did, however, not correlate with patient survival. Plasma treatment was effective in three patients, but five deceased despite treatment. Patients who deceased had a later treatment onset than survivors and finally died from multiple organ failure.
CONCLUSION: Our data indicate that the efficacy of convalescent plasma treatment of critically ill COVID-19 patients who already had developed strong antiviral immune responses and organ complications is limited.