Patients with cGVHD have defective CD24^hiCD27⁺ and plasmablast-like IL-10–producing B-cell compartments. Whole PBMCs were cultured for 66 hours with CpG-B (3 μg/mL, left panel) followed by restimulation with PMA + ionomycin in the presence of brefeldin A the last 5 hours of culture, fixed, permeabilized, and intracellular IL-10 was measured in live B-cell subsets by flow cytometry. (A) Proportions of CD19⁺CD24^hiCD27⁺IL-10⁺ cells in percentages of live CD19⁺CD24^hiCD27⁺ cells in healthy donors, patients with active cGVHD, cGVHD in remission, and AHSCT recipients with no history of cGVHD. (B) Proportions of CD19⁺CD24⁻CD38^hiIL-10⁺ plasmablast-like cells in percentages of live CD19⁺CD24⁻CD38^hi cells in healthy donors, patients with active cGVHD, cGVHD in remission, and AHSCT recipients with no history of cGVHD.