Mass COVID-19 vaccination is mandated in vulnerable populations in our renal transplant waitlist cohort. However, the anti–human leukocyte antigen (anti-HLA) profile after COVID-19 vaccination is controversial, and the side effects are yet to be discerned.


To evaluate the status of HLA antibodies in waitlist renal transplant patients before and 3 weeks after each vaccination and if comorbidities are associated with the HLA antibody profile.


A total of 59 waitlisted kidney transplant patients were included in this study. The anti-HLA antibodies were analyzed before and 6 months after their last COVID-19 vaccination. The mean fluorescence intensity change in the anti-HLA antibody levels was used to classify patients into 3 groups: high inducers, low inducers, and noninducers.


There were significant HLA antibody profile changes after COVID-19 vaccination, showing 21 antibodies generated against HLA class I antigens and 7 against HLA class II antigens to their baseline. Compared with the noninducers, the high and low inducers showed a higher prevalence of COVID-19 infection, COVID-19 vaccine type, and background hypertension history.


Our data suggest that COVID-19 vaccination propagates anti-HLA class I and II antibodies for waitlisted renal transplant patients. The clinical significance of these antibodies needs further study. Furthermore, comorbidities, such as history of COVID-19 infection and hypertension, supplemented this effect. Anti-HLA antibody monitoring may be warranted in vaccinated, waitlisted renal transplant patients with COVID-19 vaccinations, and a history of COVID-19 infection or hypertension.

This content is only available as a PDF.

Author notes

Supplemental digital content is available for this article. See text for hyperlink.

Dokouhaki, Wu, and Mostafa contributed equally as co-senior authors.

This research was funded by the College of American Pathologists (CAP) Foundation John H. Rippey Grant for Expedited Research—The Impact of Laboratory Testing for SARS-CoV-2 on Quality and Patient Safety.

Competing Interests

The authors have no relevant financial interest in the products or companies described in this article.

Data were presented, in part, at the following meetings: the 2022 Banff-Canadian Society of Transplantation (CST) Joint Meeting; September 20, 2022; Banff, Calgary, Alberta, Canada; the 2023 CST Annual Scientific Meeting; October 18, 2023; Winnipeg, Manitoba, Canada; and the 49th American Society for Histocompatibility and Immunogenetics (ASHI) Annual Meeting; October 16, 2023; San Antonio, Texas.

Supplementary data