ABO-incompatible renal transplantation at Tokyo Women's Medical University.

One hundred and forty-one patients with end-stage renal failure underwent ABO-incompatible living kidney transplantation at our institute between January 1989 and December 2001. To remove anti-A and/or anti-B antibodies, the recipients received sessions of double-filtration plasmapheresis and/or sessions of regular plasmapheresis before renal transplantation. Among the initial 53 patients, 1-4 sessions of immunoadsorption were performed before transplantation. Their anti-A immunoglobulin G (IgG)/IgM titers and/or anti-B IgG/IgM titers were reduced to 1:32 or below. Methylprednisolone, cyclosporine or tacrolimus and azathioprine or mycophenolate mofetil were used as basic immunosuppressants. Antilymphocyte globulin and deoxyspergualin were used in the majority of cases performed in the pre-MMF era (1989-1999). Local irradiation of the graft was performed before 2001, but radiation has not been used since MMF was launched in 2001. Splenectomy was done at the time of kidney transplantation in all cases except one. The patient survival rates for ABO-incompatible recipients were 94%, 94%, 88%, and 84% at one-, 5-, 10- and 13-years, respectively. These were not significantly different from those of the concurrent 777 ABO-compatible kidney transplant recipients (one-, 5-, 10- and 13-year patient survival rates of 99%, 97%, 92% and 91%, respectively). The one-, 5-, 10- and 13-year graft survival rates among ABO-incompatible recipients were 82%, 76%, 56% and 56%, respectively. The graft survival rates among ABO-compatible recipients were 96%, 85%, 67% and 58%, respectively, at the same intervals. There was a significant difference in the short-term graft survival rates between ABO-incompatible and ABO-compatible renal transplants (log-rank test, P=0.007); however, there was no difference in the long-term graft survival rate. Acute rejection episodes occurred significantly more frequently among recipients of ABO-incompatible grafts (85 of 141, 60%) compared with ABO-compatible recipients (377 of 777, 49%; P=0.010). However, with newer immunosuppressants employed since 1998, graft survival has markedly improved. The 5-year graft survival rate is now more than 90% and is not significantly different from that of ABO-compatible cases. In conclusion, ABO incompatibility is no longer an immunological risk factor for long-term outcome.