Korean J Transplant.  2023 Nov;37(Suppl 1):S94. 10.4285/ATW2023.F-6765.

Assessment of human leukocyte antigen antibody dynamics in patients awaiting kidney transplantation

• Kim EA
• Kang H
• Oh EJ

• KMID: 2551681
• DOI: http://doi.org/10.4285/ATW2023.F-6765

Abstract

Background
Although preexisting anti-human leukocyte antigen (HLA) antibodies are regularly monitored for changes in patients awaiting kidney transplantation (KT), the natural kinetics of HLA antibodies over time have yet to be fully elucidated. This study aims to investigate the dynamics of anti-HLA antibodies using the single antigen bead (SAB) assay in patients waiting KT.
Methods
A retrospective review was conducted on SAB test results of 5,757 patients (2016–2023). The inclusion criteria were met by 316 patients, with SAB assay measurements on at least two occasions, separated by a minimum interval of 6 months, and no prior history of immunosuppression. The SAB results were categorized based on the peak mean fluorescence intensity (MFI) levels into different grades: strong (10,000≤MFI), moderate (5,000 to 10,000), weak-moderate (3,000 to 5,000), weak (1,000 to 3,000), and negative (MFI≤1,000).
Results
Of 316, 198 (62.7%) and 184 (58.2%) had no changes in class I and class II MFI grades, respectively. For class I and class II antibody, 73 (22.1%) and 89 (26.3%) patients showed an increase, whereas 45 (13.6%) and 43 (12.0%) patients showed a decrease, respectively. Significant MFI changes (2 MFI grade≤) were found in 26 patients (8.2%) for class I (18 increase, 8 de-crease) and 20 (6.3%) for class II (16 increase, 4 decrease). Of 49 patients who had three or more SAB assay results, 38 patients (77.5%) did not show significant MFI changes. Interestingly, one patient, a 68-year-old woman showed spontaneous resolution of HLA antibodies (from 7,631 MFI to negative during 6 years period), despite no documented sensitization history or immuno-suppression.
Conclusions
While most patients demonstrated stable dynamics of anti-HLA antibodies, we also observed significant chang-es, including a case of spontaneous resolution. These findings highlight the individualized nature of anti-HLA antibody dynam-ics and emphasize the complexity of alloimmunity. Further investigations are necessary to elucidate the underlying mecha-nisms driving such changes and evaluate their impact on KT outcomes.