Formation of a cohort of anticovid plasma donors with high titer antibodies neutralizing SARS CoV 2

Background. The application of convalescent plasma (CP) is currently seen as a feasible therapeutic approach in the treatment of COVID-19.Aim. To analyze the experience of recruiting a donor cohort from COVID-19 convalescents for banking of CP as part of a pilot project at the Moscow Healthcare Department.Materials and methods. A retrospective research included 493 COVID-19 convalescents as potential CP donors, all examined at the Sklifosovsky Research Institute for Emergency Medicine. CP was banked using the plasmapheresis method. Only those donors with a documented medical history of COVID-19, which was confirmed by polymerase chain reaction of SARS-CoV-2 RNA in pharyngeal swabs, and no sooner than 14 days after complete recovery were eligible for donation. Viral neutralizing activity (VNA) was chosen as the key characteristic of the immunological viability of CP. All the donors having VNA titers were characterized in terms of gender, age, time interval since the disease onset, regression of clinical symptoms and clinical features of the COVID 19 course.Results. Effective (1:160 or more) and acceptable (1:80) VNA titers were found in 21.1 % and 24.75 % of donors, respectively. Significant predictors for a donor having a high VNA titer included: male sex, age over 36 years and verified viral pneumonia. The absence of a significant body temperature response (38.5 degrees C) can be considered as a negative marker of a potential donor.