*Purpose: The Coronavirus Disease 2019 (COVID-19) pandemic prompted widespread vaccination for the immunosuppressed population starting in January 2021 with minimal information on safety outcomes. The purpose of this study is to evaluate the relationship between kidney pathological changes and mRNA-based COVID-19 vaccines in three kidney transplant recipients.

*Methods: We conducted a single-center retrospective case review of three kidney transplant recipients with biopsy-proven acute rejection or pathological changes after 2-dose COVID-19 mRNA vaccination. Renal function, maintenance immunosuppressant regimens, and pathology slides at baseline and post-rejection are recorded. Possible factors associated with the development of rejection were analyzed.

*Results: All participants were male, two received related-living donor transplants and one received a deceased donor transplant. The mean age was 44.3 years. Average time from 2^nd COVID-19 vaccine to confirmed rejection or pathological changes was 33.7 days. Two patients received mRNA-1273 COVID-19 mRNA vaccine and one received the BNT162b2 COVID-19 mRNA vaccine. All three allograft biopsies demonstrated findings consistent with acute active antibody mediated rejection and thrombotic microangiopathy. One allograft biopsy also demonstrated findings consistent with collapsing focal segmental glomerular sclerosis. As of November 26, 2021, there have been over 26 reports of solid organ rejection or failure to the Vaccine Adverse Event Reporting System (VAERS) for the COVID-19 mRNA vaccines highlighting the need for further investigation.

*Conclusions: Immunization with COVID-19 mRNA vaccine has potential to precipitate clinically significant immune response to renal allografts leading to acute allograft rejection, thrombotic microangiopathy, and collapsing focal segmental glomerular sclerosis.

« Back to 2022 American Transplant Congress