MATCHING FOR HLA IN CADAVERIC RENAL TRANSPLANTATION REVISITED: MAJOR IMPACT OF THE FULL HLA-DR COMPATIBILITY ALLOWING SIMPLER AND EQUITABLE ALLOCATION OF ORGANS.

1.1
#54-OR
MATCHING FOR HLA IN CADAVERIC RENAL TRANSPLANTATION REVISITED: MAJOR IMPACT OF THE FULL HLA-DR COMPATIBILITY ALLOWING SIMPLER AND EQUITABLE ALLOCATION OF ORGANS.
Ilias Doxiadis , Johan de Fijter , Marko Mallat , Peter de Lange , Jan Ringers , Lendert Paul , Guido Persijn and Frans Claas . LUMC Immunohematology and Blood Transfusion ; LUMC ETRL ; Nephrology ; Surgery and Leiden Netherlands, Eurotransplant International Foundation .

Allocation demands a fair policy offering to patients the best possible organ, with the highest chance for long graft survival, irrespective age, sex, or race. Even with the most potent immunosuppression HLA-matching remains effective. Well-matched transplants have longer patient/graft survival lowering the chance to return to the waiting list, while the imperative of matching results to accumulation of patients with rare phenotypes. Equitable allocation is feasible: For study-1, we selected from the Eurotransplant database kidney transplants (1985-2000; N=38,286, 1st transplants) with end point graft loss censored for death with function. For study-2 we analysed similar transplants (N=479) from the Leiden database with end point biopsy proven acute rejection (AR) at 180 days. In study-1 we divided the cohort into 0 and 1 HLA-DR mismatches (DRMM) and analyzed the influence of HLA-A,B. In the 0-DRMM group the effect of HLA-A,B was highly significant (p<0.005), whereas this effect is absent in 1-DRMM. Study-2 confirmed the results. The cohort of 1-DRMM had a significant higher incidence of AR; HLA-A,B matching did not influence the relative risk (RR). Within 0-DRMM the RR increased with the number of HLA-A,B MM. The RR in all these groups was lower compared to the RR of the 1-DRMM group. These results clearly show that aiming for full HLA-DR compatibility confers more benefit than the current allocation procedure. As a full HLA-DR matched organ can be found for patients with rare HLA phenotypes, such allocation will result in shorter waiting times for these patients and an increased graft survival for the total population.