HLA and red blood cell antigen genotyping in SARS-CoV-2 convalescent plasma donors

Abstract

Background: The SARS-CoV-2 pandemic has put significant additional pressure on healthcare systems throughout the world. The identification of at-risk population beyond age, pre-existing medical conditions and socioeconomic status has been the subject of only a small part of the global COVID-19 research so far. To this day, the extent to which the red blood cell (RBC) antigens expressed by an individual can be associated with SARS-CoV-2 infection or clearance remains unknown. Methods: The phenotypes for ABO and RhD and the genotypes for 37 red blood cell (RBC) antigens were determined using high throughput platforms in 90 Caucasian convalescent plasma donors. The antigen frequencies were compared to the expected Caucasian frequencies using Z-tests for two-proportion. Results: The AB phenotype and FY*A genotype frequencies were both independently and significantly increased (1.5x, p=0.018 and 2.2x, p=0.028, respectively) in the convalescent cohort (N=90) compared to reference frequencies. The AB phenotype was also significantly overrepresented (3.2x, p=0.028) within the FY*A sub-group (N=23). The O group was underrepresented within the cohort proportionally to the AB increase, although non-significantly (p=0.110). No other significant RBC antigen expression patterns in the convalescent Caucasian population were identified. Conclusion: Altogether, our study reveals ABO and Duffy RBC antigen variation among surviving, non-hospitalized COVID-19 patients turned convalescent plasma donors and contributes to the global advancement in understanding COVID-19 potential risk factors.