Th1/Th2 cytokine profiles and their relationship to clinical features in patients following nonmyeloablative allogeneic stem cell transplantation

An imbalance in helper T-cell type 1 (Th1) and type 2 (Th2) cytokines is suggested to play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD). The aim of this study was to investigate the cytokine bias acquired by T cells after transplantation and its possible influence on relapse of original malignancy. Cytokine levels by peripheral CD4 and CD8 T cells were tested at various pre- and post-transplant time points with fluorescein isothiocyanate-based intracellular cytokine assay after short-term in vitro mitogenic stimulation (phorbol myristate acetate + ionomycin). In both CD4+ and CD8+ cells, interferon (IFN)-gamma-producing cell populations increased, indicating a shift to a Th1 cytokine profile with aGVHD. IFN-gamma-producing T cells was significantly lower in patients who experienced relapse of original disease compared to those who showed no signs of relapse and compared to normal controls. Our studies demonstrate that aGVHD correlates with a Th1 bias and that Th1 response may potentiate an effective immune surveillance.