Reconstitution of cytotoxic T lymphocyte activity following allogeneic bone marrow transplantation in man.

Longitudinal studies over an eight-month period have been performed to follow the T killer response restoration after allogeneic bone marrow transplantation (BMT). The capacity of the patient's peripheral blood mononuclear cells (PBM) to develop cytotoxic effector cells directed either against allogeneic cells or against Epstein-Barr virus (EBV) or Herpes-simplex virus-1 (HSV-1)-infected syngeneic cells was tested monthly. The data suggest that in most cases the cytotoxic T lymphocyte (CTL) activity, either allospecific or directed against EBV and the HSV-1 specific killer (HNK) responses, is quickly reconstituted in BMT patients. Roughly, these activities seem to be normal after two months following classic nondepleted grafting. However, in the two patients who had received a T-cell-depleted graft, the restoration was delayed. Furthermore, in the majority of the patients, once reconstituted the killer responses were relatively stable and the occurrence or absence of graft-versus-host diseases (GVHD) did not significantly modify these responses.