BAFF/B-cell ratio and BAFF-R detection after rituximab in cGVHD. (A) Serial BAFF measurements before and after rituximab in patients with stable/improved cGVHD compared with unresponsive cGVHD 2 years after rituximab. (B) Comparison of BAFF/B ratios in patients at 2 years with stable/improved disease or unresponsive cGVHD. (C) Representative flow cytometry showing BAFF-R expression on CD19⁺ B cells in stable/improved cGVHD versus unresponsive cGVHD. (D) Frequency of BAFF-R⁺ CD19⁺ B cells in the 2 groups. (E) Representative flow cytometric analysis showing that CD20 expression on CD19⁺ gated B cells is low in progressive cGVHD after rituximab. (F) Comparison of cell surface expression of CD20 (in MFI) between patients with stable/improved versus unresponsive cGVHD after rituximab.