IL2-DEPENDENT AND IL4-DEPENDENT PROLIFERATION OF T-CELL CLONES DERIVED EARLY AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION - STUDIES OF PATIENTS WITH CHRONIC MYELOGENOUS LEUKEMIA

In an attempt to explore T-cell functions shortly after allogeneic bone marrow transplantation more fully, IL2- and IL4-dependent proliferation was assessed on CD4+ TCR-alpha-beta+ T-cell clones derived 4-6 weeks after transplantation. Both allogeneic pooled peripheral blood mononuclear cells and Epstein-Barr virus-transformed B-cell lines (BCL) could function as accessory cells (AC) for PHA activation of T-cell clones. Although minimal clonal proliferation was seen when the T-cell activation signal was BCL + PHA + IL4, a majority of the clones could undergo IL4-dependent proliferation after previous activation with AC + PHA + IL2. For certain clones, IL4 also showed an additive effect with IL2. Thus, IL4 was a growth factor for a majority of the investigated posttransplant T-cell clones, and in vivo modulation of IL4-dependent T-cell functions may this become a future therapeutic possibility to enhance graft-versus-leukaemia effects in bone marrow transplant recipients.