CD27⁺ B cells in patients with cGVHD are enlarged compared to CD27⁻ B cells. (A) Cell size analyzed by forward scatter (FSC) of CD27⁻ and CD27⁺ B-cell subsets from patients with cGVHD incubated in complete media for 24 hours. Left: Histograms show CD27⁻ B cells (shaded area, thin line) and CD27⁺ (open area, bold line) from a patient with active cGVHD. Right: Median of FSC quantified in CD27⁻ and CD27⁺ B cells from patients with active cGVHD. Data are median ± range from a single experiment; n = 3. *P = .042 (unpaired 2-tailed t test). (B) Imaging by light microscopy of IgD⁺ CD38^Hi CD27⁻ B cells and IgD⁺ CD38^Hi CD27⁺ B cells from a patient with cGVHD incubated for 24 hours. Original magnification ×40.