Proportions of immature CD19+CD21− B lymphocytes predict the response to extracorporeal photopheresis in patients with chronic graft-versus-host disease

To the editor: B lymphocytes are increasingly assigned an important role in the pathogenesis of auto-and alloimmune diseases including chronic graft-versus-host disease (cGVHD)[1][1][⇓][2][⇓][3]–[4][4] where abnormalities of B-cell homeostasis in patients with active cGVHD have been observed