HLA Diagnostics: Evaluating DSA Strength by Titration.

HLA antibodies, and specifically donor-specific-HLA antibodies, play a key role in transplant-related diagnostics and decision-making. It is now clear that the simple differentiation between absence and presence of HLA donor-specific antibodies does not provide sufficient granularity in all clinical circumstances. It addition, knowledge of HLA antibody strength has potential utility at different stages of recipient evaluation along the transplant timeline from initial pretransplant evaluation, evaluation of a specific potential donor, and posttransplant monitoring for de novo donor-specific antibodies. Here we compare data evaluating HLA antibody strength using the conventional IgG-mean fluorescence intensity approach with serial dilution studies (titration) and of C1q binding (C1q-mean fluorescence intensity). The added value of titration studies along the 3 milestones of the transplant cycle is emphasized.