SECRETION OF LEUKEMIA INHIBITORY FACTOR AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION - A STUDY OF CD4(-ALPHA-BETA(+) T-CELL CLONES DERIVED FROM 4 LEUKEMIA PATIENTS() AND CD8(+) TCR)

CD4(+) and CD8(+) TCR alpha beta(+) T-cell clones were derived from 4 leukaemia patients early (4-6 weeks) after allogeneic bone marrow tran splantation. Leukemia inhibitory factor (LIF) secretion in response to the activation signal accessory cells (AC) + phytohaemagglutinin (PHA ) was investigated for each individual clone. Only a minority of CD4() TCR alpha beta(+) T-cell clones secreted LIF in response to AC + PHA , whereas most T-cell clones were capable of LIF secretion when exogen ous interleukin 2 was added together with AC + PHA. LIF secretion coul d also be demonstrated for CD8(+) TCR alpha beta(+) posttransplant T-c ell clones. Thus, posttransplant CD4(+) and CD8(+) TCR alpha beta(+) c lonogenic T-cells are capable of LIF secretion, and LIF secretion may be a T-cell effector mechanism in graft versus host disease, graft ver sus leukaemia effects or posttransplant haematopoietic reconstitution.