Expansion of peripheral helper T cells in the peripheral blood of patients with chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD), presented as an autoimmune-like syndrome, is an important late complication and has become the leading cause of non-recurrent death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). A cohort of 52 cGVHD patients were analyzed for the presence of Tph cells, circulating follicular helper T (cTfh) cells and B cells in peripheral blood mononuclear cells (PBMCs). We found decreased frequency of cTfh cells, but increased frequency of Tph cells in post-transplant patients compared to healthy controls (HCs). Higher percentage and absolute number of CCR2⁺Tph cells were observed in cGVHD patients. The percentage and absolute number of Tph cells decreased significantly with anti-cGVHD therapy. The percentage of Naive B cells, Breg cells and pre-GC B cells was negatively associated with Tph cells. The absolute number of plasma cells was positively associated with the absolute number of Tph cells. The percentage and absolute number of post-GC B cells were both positively associated with Tph cells expression. Collectively, our results showed that Tph cells are involved in the development of cGVHD and correlate with the severity of the disease.