THE PHENOTYPE AND RECONSTITUTION OF IMMUNOREGULATORY T-CELL SUBSETS AFTER T-CELL-DEPLETED ALLOGENEIC AND AUTOLOGOUS BONE-MARROW TRANSPLANTATION

In the present study, we examined changes in the expression of CD45RA, CD31, and CD29 on total CD4 and CD8 lymphocytes in patients who had r eceived CD6 T cell-depleted allogeneic marrow and received no immune s uppressive drugs after engraftment in order to identify defects in rec onstitution of immunoregulatory T cells after allogeneic BMT. Results following allo-BMT were compared with normal controls and patients fol lowing autologous BMT. We showed that CD4(+)CD45RA(+), CD4(+)CD29(+) ( CD29(high)), and CD4(+)CD31(+) cells were markedly decreased during th e first 24 months after allo- and auto-BMT. CD8(+)CD45RA(+) cells reco vered to normal levels within the first month after auto-BMT, while af ter allo-BMT, the CD8(+)CD45RA(+) cells were at slightly low levels du ring the first month, but gradually increased to normal levels by 12 m onths post-BMT. CD8(+)CD29(+) cells were increased during the first 12 months both after allo- and auto-BMT although during the first month, a decreased percentage of CD8(+)CD29(+) cells was observed in allo-BM T patients. More important, CD4(+)CD29(+), CD8(+)CD29(+), and CD8(+)S6 F1(+) cells were significantly increased in patients with moderate-to- severe acute GVHD (grades II-IV) compared with those with or without m ild acute GVHD (grade I), suggesting that CD4 helper-inducer (CD4(+)CD 29(high)) and CD8 killer-effector (CD8(+)CD29(high)SGF1(+)) cells play an important role in the pathophysiology of acute GVHD.