Kinetics of pDCs, mDCs, γδT cells and regulatory T cells in association with graft versus host disease after hematopoietic stem cell transplantation

Introduction: Although the roles of each low-frequency immunocompetent cells such as dendritic cells (DCs), gamma delta T cells, and Treg cells in induction of acute or chronic graft versus host disease (GVHD) have been discussed in several reports, there are few papers dealing with an evaluation of these immunocompetent cells together and simultaneously in patients with hematopoietic stem cell transplantation (HSCT) and explored the kinetics of these cells in association with GVHD. Methods: In the present study, we assessed the number of plasmacytoid DCs (pDCs), myeloid DCs (mDCs), gamma delta T cells and Treg cells serially in patients who received allogeneic HSCT and analyzed the relationship of these cells with acute or chronic GVHD (cGVHD) by using flow cytometry. Results: The percentages and numbers of pDCs, mDC1s and gamma delta T cells were significantly lowered in the patients with acute GVHD (aGVHD) compared with those with no GVHD. On the contrary, the percentages and numbers of Treg cells were significantly elevated in the patients with aGVHD compared with those with no GVHD. As to the association with cGVHD, Treg cells were elevated in the patients with cGVHD, compared with those with no GVHD. Conclusion: The present study revealed an association of pDCs, mDCs, gamma delta T cells and Treg cells with induction or treatment of GVHD.