Developing role of B cells in the pathogenesis and treatment of chronic GVHD

Chronic graft‐versus‐host disease (cGVHD) is a major complication affecting the long‐term survival of patients after allogeneic haematopoietic stem cell transplantation. The mechanism of cGVHD is unclear, and while previous studies have primarily focused on T cells, the role of B cells in the pathogenesis of cGVHD has been less reported. However, current studies on cGVHD are increasingly focused on the important role of B cells. In this review, we will introduce the newest studies and examine the role of B cells in cGVHD in detail with respect to the following aspects: altered B cell subpopulations, aberrant B cell signalling pathways, autoantibodies and T‐B cell interactions. Treatment strategies for the targeting of B cells during cGVHD will also be discussed.