Expression of active transcription factor IRF5 is upregulated in B cells of patients with active cGVHD. Nuclear protein fractions were isolated from B-cell pellets from patients with active (n = 4), inactive (n = 1), and no (n = 3) cGVHD using a commercially available extraction kit and (A) IRF5 protein expression was measured by western blot analysis. α-tubulin (cytoplasmic) and Rb (nuclear) were used as loading controls. (B) IRF5 expression levels were expressed as a fold change of normalized levels in the no/inactive cGVHD group. Rb was used to normalize IRF5 nuclear gene expression levels. The Image J software program was used for quantification. ∗P < .05 between sample groups. Data represent median ± range.