Impact of Combined HLA-DRB1/DQB1 Matching On Deceased Donor Kidney Graft Survival: Review of OPTN Data.

Abstract

Purpose: Matching for DRB1 (DR) has been associated with significantly improved graft survival (GS). Recent publications have identified DQB1 (DQ) as a frequent target of post-transplant DSAs. This study tests the hypothesis that HLA-DR and -DQ matching is superior to DR matching alone and the consideration of utilizing DQ matching in organ allocation. Methods: Results from 16,329 deceased donor (DD) transplants performed from 2005-2007, with up to 8 yrs. of follow up, were studied. Recipients were excluded if they received a multi-organ transplant or if the DR/DQ mismatch (MM) was unknown. Pairs were excluded if DQ typing of either individual was reported as a “broad” antigen. Results are based on OPTN data. Results: During this time period, ˜21% of patients received a 0 DR MM graft with 69% also being a 0 DQ MM. Among 1 and 2 DR MM recipients, 84% and 96%, respectively, were MM for at least 1 DQ antigen. Among all recipients, 77% were were at least a 1 DQ MM. The 0DR/0DQ group showed a significant GS advantage (p <0.05), within 4 yrs. post-Tx, when compared to all other groups except 0/1 and 0/2. Within DR MM groups, a higher DQ MM was not associated with a decrease in GS.Figure: No Caption available.Conclusions: These data show that improved kidney GS among recipients of DD kidneys is linked to better DR matching which appears to be independent from the degree of DQ MM. Although recipients with lower DR/DQ MMs enjoyed better GS, the GS advantage appeared to be dictated by the degree of DR MM. However, higher resolution DQ typing may be required to detect clinically relevant DQ disparities. Importantly, the observation that 31% of 0 DR MM recipients and >80% of recipients with >1 DR MM had at least one DQ MM may explain the high frequency of DQ antibodies observed post-transplant. Thus, increasing the proportion of 0 DR MM’d transplants would also decrease the incidence of DQ MM’d transplants. These results support the continued use of allocation points for DR matching and warrant further studies to determine if the current point values are sufficient.