Delayed reconstitution of B cells and increased proportion of CD27⁺ B cells in patients who develop cGVHD. CD19⁺ B-cell number (left y-axis) and BAFF levels (right y-axis) were measured every 3 months after HSCT in 3 patient groups. (A) Eight patients who did not develop cGVHD by 12 months. (B) Seventeen patients who developed cGVHD during this period. (C) Eight patients who underwent autologous transplantation after myeloablative conditioning. Numbers of patients measured at each time point are shown. The percentage of CD27⁺ B cells was measured every 3 months after HSCT. (D) Patients who did not develop cGVHD by 12 months are compared with (E) patients who developed cGVHD during this period. Absolute numbers of CD27⁻ B-cell subsets were also identified in these patients. (F) Results in patients who do not develop cGVHD between 3 and 12 months after HSCT are compared with (G) patients who developed cGVHD during this period.