T LYMPHOCYTE RECONSTITUTION IN LONG-TERM SURVIVORS AFTER ALLOGENEIC AND AUTOLOGOUS MARROW TRANSPLANTATION1

T cell subsets and their immune reactivities were studied in long-term survivors after bone marrow transplantation and the results of autotransplanted and allotransplanted patients were compared. These two groups of patients (4 autotransplants and 4 allotransplants) were roughly comparable in terms of their underlying diseases, pretransplant conditioning regimens, supportive care, and posttransplant sampling days for immunological studies. Significant differences were observed between autologous and allogeneic marrow recipients in the total number of OKT3-, OKT4-, OKT8-, and OKIa1 -positive cells. Similar differences were observed between transplant patients and normal controls. Decreased OKT4 cells and increased OKT8 cells resulted in inversion of the OKT4:OKT8 ratio, which was significantly lower in allotransplanted compared with autotransplanted patients, and both groups of transplant patients showed depressed responses in comparison with normal controls. In contrast, there were no significant differences in MLR reactivities between transplanted patients and normal controls. When mitogenic responses were analyzed in relation to T cell subsets, phytohemagglutinin responsiveness showed a significant correlation with OKT4:OKT8 ratios (P less than 0.01) and the proportions of cultured OKT4 cells (P less than 0.01). These observations suggest that T lymphocyte reconstitution is still incomplete or abnormal in long-term survivors regardless of the type of graft. Furthermore, abnormalities observed in these long-term survivors were characterized by an imbalance of T cell subsets that was more profound in allotransplanted than in autotransplanted patients.