Present status of ABO-incompatible kidney transplantation in Japan

Background:We have been making continuous efforts in ABO-incompatible kidney transplantation since 1989 to expand the opportunities for kidney transplantation from living donors in Japan. Patients and method:From the Japanese registry, we reviewed the long-term patient and graft survival of ABO-incompatible kidney transplantation. This survey focused on 564 patients who received ABO-incompatible kidney grafts from January 1989 to December 2003 in whom monitoring follow-up could be achieved in 60 institutions all over Japan. The mean age of 367 (65%) male and 197 (35%) female patients at surgery was 34.5 yr. Pre-operative anti-A/B antibody (Ab) removal and splenectomy (n=553, 98%) were routinely performed combined with triple or quadruple immunosuppression using calcinurine inhibitor (CNI), anti-metabolites and steroids with or without deoxyspurgualin (DSG) or anti-lymphocyte Abs. Results:The overall patient survival rate at 1, 3, 5 and 10 yr after transplantation was 94, 91, 88 and 81%, with overall graft survival rates of 86, 82, 74 and 53%, respectively. The graft survival rate was significantly higher in patients aged 29 and younger compared with those aged 30 and older. Children aged 15 or younger in particular have shown excellent graft survival rates at 1, 3, 5 and 10 yr of 90, 90, 86 and 76%, respectively. Patients with anticoagulation therapy (n=285) showed a significantly higher graft survival rate than those without anticoagulation (n=213), with 10-yr graft survival rates of 59 vs. 48%. There were no significant differences between A and B incompatibility with respect to clinical outcomes. There were also no significant difference in numbers of human leukocyte antigen mismatches, induction and maintenance CNI (cyclosporin A (CYA) vs. tacrolimus) and donor/recipient relationships with respect to the outcomes. We divided the patients into five groups according to the transplanted year periods. The outcome of the most recent 124 cases since 2001 had dramatically improved, with 2-yr graft survival of 94%, and there is a significant difference between the groups in 2001 onwards and the other four groups. Conclusion:This study confirms that the long-term outcome of ABO-incompatible living kidney transplantation is excellent and is similar to that of ABO-compatible cases. Recent data show that short-term graft survival has also improved. ABO-incompatible kidney transplantation is a radical, but safe and effective, treatment choice for end-stage renal disease.