Different γ/δ T clones sustain GVM and GVH effects in multiple myeloma patients after non-myeloablative transplantation

TCR γ/δ profiles were analyzed in 13 multiple myeloma patients after allogeneic non-myeloablative transplantation.Results show that both aGVHD and minimal residual disease (MRD) eradication did significantly affect TCR γ/δ profile.During follow-up, six patients developed an aGVHD episode; in five of them, this event fitted with a modification of the TCR profile.Eleven patients achieved PCR-negativity during follow-up. In the 90% of them, the appearance of a new predominant TCR peak was concomitant to the disappearance of the IgH clone.These results suggest that different T γ/δ populations would sustain GVM and GVH effects after non-myeloablative allogeneic transplant.