The allogeneic CD4+ T-cell-mediated graft-versus-leukemia effect.

CD4+ T-cells have emerged as important cells in the initiation and delivery of the GVL response. Nevertheless it seems likely that they act in concert with other T-cells and NK cell effectors to produce the full in vivo effect of GVL. How they interact with other effectors is yet to be determined. Furthermore it is very likely that different hematological malignancies have different susceptibility to attack by various lymphocyte subsets, depending upon their MHC expression, nature of the antigens presented and other properties not yet defined. Here we specifically focus on the role of CD4+ T-cells in mediating GVL, particularly in chronic myeloid leukemia. Candidate antigens recognised by CD4+ cells are described and new approaches to GVL modulation in clinical bone marrow transplantation are discussed.