(Background) T-cell receptor (TCR) Vδ2 γ δ T cells (Vδ 2 cells) participate in host defense, whereas Vδ 1 γ δ T cells (Vδ 1 cells) may regulate immune responses. We and others earlier demonstrated that Vδ 1 cells predominated over Vδ 2 cells in the peripheral blood in immunosuppression (IS) free state, referred to operational tolerance, after human liver transplantation (Tx). In addition, our recent investigation revealed that liver Tx operational tolerance was characterized by up-regulation of INTRAGRAFT V δ 1/V δ 2 cell ratio and the presence of 100% homologous TCR sequence of V δ 1 cells among recipients. (Methods) Biopsy samples were obtained from intestinal grafts and native intestines of almost IS free (almost tolerant) intestinal Tx recipients. The V δ 1/V δ 2 cell ratio was assessed at the transcriptional level and the complementarity-determining-region (CDR3) loop of the δ chain was sequenced. (Results) From 4 almost tolerant recipients, 8 samples were obtained from intestinal grafts and 4 samples were obtained from native intestines by endoscopy. The V δ 1/V δ 2 cell ratio did not differ between graft and native intestines (graft and native:0.014±0.013 and 0.0058±0.0096)( ^nsP=0.23). No identical (100% homologous) CDR3 sequence of Vδ 1 cells was detected among 4 almost tolerant recipients.(Conclusions) Unlike liver Tx operational tolerance, almost tolerant intestinal Tx was NOT characterized by up-regulation of INTRAGRAFT V δ 1/V δ 2 cell ratio or the presence of any identical (100% homologous) TCR sequence of V δ 1 cells among recipients. Further studies are needed to elucidate the implication of different γ δ T cell profiles within accepted grafts between immunoprivileged liver and highly immunogenic intestine.

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