Chronic GVHD: B cells come of age

The pathophysiology of chronic graft-versus-host disease (GVHD) in humans remains poorly understood. While donor T cells play a major role, B cells have emerged in the past few years as significant actors too. In this issue of Blood , 2 papers add important advances to our knowledge of how B-cell subsets are implicated in the protean forms of the disease and how these subsets are affected by treatment with Rituximab.