Successful transplantation of blood group A2 kidneys into non-A recipients

The ABO subgroup A2 has been reported to be less reactive with the anti-A1 antibody naturally occurring in the serum of group O and B recipients and to occur in approximately 20% of group A individuals. Between March 1986 and February 1987, the Midwest Organ Bank (MOB) in Kansas City, screened all group A renal donors for the A2 subgroup. A total of 190 cadaverdonor kidneys were retrieved during this time, of which 68 were subgroup A1 and 16 were subgroup A2 (incidence of A2 = 19% of As and 8.5% of all donors). Of the subgroup A2 kidneys, 13 were transplanted into 9 group O and 4 group B recipients. One group O recipient received an HLA-identical A2 living-related graft. Recipients were not preselected or modified by splenectomy, plasmapheresis, or other means, and were treated with cyclosporine, steroids--and, in most cases, azathioprine, after transplantation. There was one hyperacute rejection and there were 5 acute cellular rejection episodes, 3 of which were reversed. One additional patient died at 2.5 months with a functioning graft. Including the successful living-related graft, 10 of 14 patients (71%) have functioning grafts, with a follow-up of 5 to 14 months, and a mean creatinine of 1.7 mg/dl. We find that the A2 subgroup represents a small but important minority of A donors, and that transplantation into non-A recipients can generally, but not universally, be safely accomplished. We recommend the screening of A donors for the A2 subgroup in both the cadaver-donor and living-related groups, and suggest that the utilization of A2 donors in non-A patients may contribute to the transplantation of group O and highly sensitized patients--and, in some cases, improve the degree of HLA matching.