The predictors of high titer of anti-SARS-CoV-2 antibody of convalescent plasma donors

BACKGROUND: Recent evidence suggested that the higher titers of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody from convalescent plasma donors contributed to the clinical improvement in coronavirus disease 2019 (COVID-19) patients. However, the titers of anti-SARS-CoV-2 antibodies varied in each individual, and the precise factors that might govern such variation have not been elucidated. OBJECTIVES: To assess the factors associated with high titers of anti-SARS-CoV-2 antibody among COVID-19 convalescent plasma (CCP) donors. METHODS: A cross-sectional study was conducted in Saiful Anwar General Hospital, Malang, Indonesia. Information of interest including demographic characteristics, clinical symptoms, comorbidities, laboratory findings, and the titers of anti-SARS-CoV-2 antibody among COVID-19 CCP donors were collected. The correlation was assessed using multiple logistic regression. RESULTS: A total of 50 COVID-19 CCP donors with the titers of anti-SARS-CoV-2 antibody of more than 1:320 and 33 donors with the titers of less than 1:320 were analyzed. Our analysis revealed that CCP donors with history of cough, fever, dyspnea, and pneumonia significantly had higher titers of anti-SARS-CoV-2 antibody compared to asymptomatic donors. Moreover, CCP donors with elevated levels of eosinophils and immature granulocytes and low levels of albumins had higher levels of anti-SARS-CoV-2 antibody. The titer of antibody was not affected by comorbidities of donors. CONCLUSIONS: CPP donors who had experience of symptomatic COVID-19 with high eosinophils level, high immature granulocytes and low albumin level have higher titers of anti-SARS-COV-2 antibody than those who experienced asymptomatic COVID-19. Our current findings may be used as the additional baseline criteria for selecting the donors of CCP for the management of COVID-19.