Anti‐human leukocyte antigen and anti‐ABO antibodies after SARS‐CoV‐2 mRNA vaccination in kidney transplant recipients.

Introduction: In this study, we evaluated whether SARS‐CoV‐2 mRNA vaccines induce anti‐human leukocyte antigen (HLA) antibodies and anti‐ ABO blood type antibodies (ABOAb) in kidney transplant recipients (KTRs). Methods: Sixty‐three adult KTRs with functioning grafts who received two doses of the SARS‐CoV‐2 mRNA vaccine were enrolled in this cohort. Changes in anti‐ABO blood type immunoglobulin IgM and IgG antibody titers, flow panel reactive antibody (PRA), de novo donor‐specific anti‐human leukocyte antigen antibodies (DSA), and kidney allograft function before and after vaccination were evaluated. Results: Only one patient experienced conversion from negative to positive flow PRA after vaccination. However, there was no DSA in single antigen flow‐bead assays. The mean fluorescence intensity (MFI) in the eight DSA‐positive recipients did not significantly change before and after vaccination (p =.383), and no additional DSA was produced after vaccination in those patients. No significant elevation of ABOAb titer was observed for either IgM (p =.438) or IgG (p =.526) after vaccination. There was no significant deterioration in estimated glomerular filtration rate (eGFR) after vaccination (p =.877) or elevation of the urine protein‐to‐creatinine ratio (p =.209) after vaccination. One episode of AMR was observed in addition to a preexisting acute cellular rejection. Conclusions: The SARS‐CoV‐2 mRNA vaccine did not induce anti‐HLA antibody or ABOAb production in KTRs. [ABSTRACT FROM AUTHOR]