CD19⁺ B cells and BAFF/B cell ratio in cGVHD patients with dysgammaglobulinemia. (A) cGVHD patients with hypogammaglobulinemia have a significant CD19⁺ B-cell deficiency. “Hyper Ig” represents cGVHD patients with IgG more than 1600 mg/dL, “Hypo Ig” with IgG less than 700 mg/dL, and “Normal Ig” with IgG 700 to 1600 mg/dL. Lines indicate the range of CD19⁺ B cells in healthy persons. Data are shown as box plots. (B) Significant elevation of BAFF/B-cell ratios (nanograms per 1 × 10³ B cells) in patients with cGVHD and dysgammaglobulinemia. Data are shown as box plots. ○ represents outliers.