Impact of preexisting circulating effector T cells on the outcome of ABO-incompatible adult LDLT.

Our aim was to clarify the significance of phenotype of circulating CD8 T(+) cells on the outcome of ABO-incompatible (ABO-I) living donor liver transplantation (LDLT). Twenty-six recipients undergoing ABO-I LDLT and 92 undergoing ABO-compatible (ABO-C) LDLT were classified into three groups according to preoperative proportion of CD8 T(+) cells: naive-dominant (group I), effector memory-dominant (group II), and effector-dominant (group III) recipients. The clinical courses were analyzed. The results showed that in ABO-C groups I and II and in ABO-I group I, effector cells remained above the pretransplant levels after tacrolimus administration. However, in ABO-C group III and ABO-I groups II and III, effector cells were down-regulated for a prolonged period, along with markedly decreased perforin expression and frequent life-threatening complications. ABO-I group II and group III recipients had higher infection rates. It was concluded that recipients with preexisting high effector CD8 T(+) cells are unfavorable candidates for ABO-I LDLT.