Abstract
HLA mismatches (HLA-MM) have been shown to affect survival after heart transplantation (HTX). However, it is generally felt that current immunosuppressive therapies (IS) minimize the effects of HLA-MM. This study wishes to test the hypothesis that despite advances in IS, HLA-MM still plays a predictive role in determining outcomes.
We retrospectively analyzed survival and freedom from immunologic adverse events on all patients undergoing HTX at our institution between 2005 and 2012 (n=129). Groups were stratified by number of HLA-MM at HLA-A, B, DQ and DR (Group 1, 3-4 MM) (Group 2, 5-6 MM) (Group 3, 7-8 MM). Events considered as adverse were biopsy-proven rejection (BPR) (ISHLT grade > 2R), allograft dysfunction (EF < 50% at ≥ 7 days post-transplant) and death from cardiac causes. Time-to-event and survival functions were calculated using the Kaplan-Meier method. IS consisted of tacrolimus/mycophenolate/steroids in 98% and tacrolimus/steroids in 2%. Induction with thymoglobulin was used in 14 % (18/129), and with basiliximab in 5% (6/129).
100% of patients had > 3 MM. Group 1-15/129, (12%), Group 2-59/129 (46%), Group 3-55/129 (43%). Freedom from adverse events and survival were significantly worse in patients with >4 MM (Group 2 and 3) (Figure 1).
Despite the use of triple-drug immunosuppression including tacrolimus in our patients, HLA-MM remains a significant predictor of adverse events and survival. Given this, novel immunologic strategies to abrogate the effect of HLA-MM are urgently needed.