TEN-YEAR EXPERIENCE IN TRANSPLANTATION OF A2KIDNEYS INTO B AND O RECIPIENTS1

Abstract

This article summarizes our 10-year multicenter experience with transplantation of 50 blood group A 2 and A 2 B kidneys into B and O patients. Since 1986, we have transplanted kidneys from 46 cadaver donors and 4 living donors who were blood group A 2 (47 donors) or A 2 B (3 donors) into 19 B and 31 O patients. In 1991, we began allocating these kidneys preferentially to B and O recipients who were selected based on a history of low (≤4) anti-A IgG isoagglutinin titers. Immunosuppression was no different from that used in ABO-compatible grafts. The 1-month function rate before thus selecting the patients was 68%(19/28), but is now 94% (17/18). Two-year cadaver-donor graft survival with this selection method is 94%, compared with 88% for 640 concurrent and consecutive ABO-compatible transplants (log-rank, 0.15). All four living-related transplants are still functioning, with a mean follow-up of 71 months. Since we began allocating A 2 kidneys preferentially to B and O recipients, the percentage of the B patients who received A 2 or A 2 B kidneys has increased from 29% (8/28) to 55% (10/18). Transplantation of A 2 or A 2 B kidneys into B and O patients is clinically equivalent to that of ABO-compatible transplantation when recipients are selected by low pretransplant anti-A titer histories. This approach increases access of blood group B recipients to kidneys.