HLA-DR Matching Is Associated With Improved Graft Survival in Recipients of Deceased Donor Kidneys. Review of OPTN Data.

Abstract

Purpose: In May of 2003, Organ Procurement and Transplantation Network (OPTN) policy was amended to allow candidates for deceased donor kidneys HLA allocation points only for DRB1 (DR) matching; points for HLA-A and -B were removed. Candidates are given 2 points if there are no mismatched (MM) DR antigens. To assess the efficacy of this policy change the OPTN Histocompatibility Committee reviewed 8 yr. outcomes data stratified by the degree of DR MM. Methods: Results from 16,329 deceased donor (DD) kidney transplants performed from 2005-2007, with up to 8 years follow up, were analyzed. Recipients were excluded if they received a multi-organ transplant or if the level of DR mismatch (MM) was unknown. Pair-wise comparisons were made between 0, 1, and 2 DR MM groups. All results are based on OPTN data. Results: During this time, 20.9% of patients received 0-DR MM grafts, 41.5% 1 DR MM, and 37.6% 2 DR MM. Graft survival (GS) was significantly better for 0 DR MM transplants compared to 1 or 2 MMs (p <0.001). A single DR MM was sufficient to confer a statistically significant decrease in GS which was evident within 4 yrs. post transplant. For 0 DR MM transplants, 57% were also 0 AB MM. Interestingly, among the 0 MM DR group; 69% were also 0 MM for HLA DQ.Figure: No Caption available.Conclusions: These data demonstrate the GS benefit of DR matching among recipients of DD kidneys and supports the utility of awarding allocation points for DR match. Recipients with lower DR MMs enjoyed significantly better GS by 4 years post transplant. Importantly, more than half of the 0 DR MM group was also 0 AB MM suggesting that the 0 MM allocation policy is a predominant factor resulting in better DR matching. These results support the continued use of allocation points for DR matching and warrant additional analyses to determine if the current point values are adequate given the improved GS.