Safe transplantation of blood type A2 livers to blood type O recipients

Background. Transplantation of blood type A subgroup 2 (A2) livers into non -A recipients has not been reported previously. A2 to O renal transplantati on has been reported, with early results including some accelerated rejecti ons and graft losses. This has led some to selectively offer A2 renal trans plantation only for patients with low anti-A titers, Given the different cl inical behavior of liver allografts to preformed antibody, we felt that suc h restriction was unnecessary. Methods. We performed six cases of A2 to O liver transplantation with no au gmented immunomodulation or restriction with regard to antibody titers, Cli nical courses, anti-A titers, rejection rates, and graft and patient surviv al were evaluated. Results. All six patients had high pretransplant anti-A titers (>1:8), and all six grafts functioned normally. There were nine rejections in the six p atients, of which three were severe (steroid-resistant) and five were late (>90 days). No rejection was vascular, and no grafts were lost, with mean f ollow-up of 665 days, In one patient who had anti-A antibody measured at th e time of rejection IGM titers increased from baseline. Currently all patie nts are home with normal function, Conclusions. We found that transplantation of blood group A2 livers into bl ood group O recipients is safe and can be performed without graft loss and without regard to anti-A titer level. The rate of acute cellular rejection is high in this small series, and a significant proportion of these events were late or required OKT-3, We did not rely on plasmapheresis or anti-a ti ter determinations. However, the potential for late rejection prompts us to consider the addition of a third immunosuppressive agent. The transplantat ion of A2 livers into O recipients can partially compensate for the more fr equent use of O livers in recipients from other blood groups.