GAMMA-DELTA T-CELLS PLAY NO MAJOR ROLE IN HUMAN HEART ALLOGRAFT-REJECTION

To investigate the role of gamma delta T cells in human heart transpla ntation, Fee searched for this T cell population in endomyocardial bio psies as well as in T cell lines and clones derived from graft-infiltr ating lymphocytes. The number of gamma delta T cells in endomyocardial biopsies from transplanted patients (n=55) was mostly low and did not differ significantly from nontransplanted patients (n=21). Moreover, there was no association of gamma delta T cell distribution with rejec tion status or with time posttransplantation. Graft-derived T cell lin es were established in the presence of autologous feeder cells and rec ombinant interleukin-2 to favor the growth of in vivo-activated T cell s. Twenty T cell lines analyzed by flow cytometry showed low percentag es of gamma delta T cells, and we were unable to obtain gamma delta T cell clones for functional studies. These results show that gamma delt a T cells are poorly expressed on human heart allograft infiltrates an d indicate that, when present, they are not activated in the graft. Ou r data suggest that gamma delta T cells do not have a major role in hu man heart rejection.