Increased Tfh cells in cGVHD. B10.BR mice were transplanted with BM only or BM and splenic T cells from B6 donor mice and spleens were harvested on day 60. (A) Representative spleens harvested from BM only and BM plus spleen mice on day 60 showing CD4 (blue), PD-1 (green), and peanut agglutinin (PNA) (red) or (B) CD19 (blue), GL7 (green), or PNA (red). Arrows indicate GC areas. (C) Composition of B cells in the spleen and peritoneal cavity. (D) Frequency of Tfh cells and (E) GC B cells. *P < .05; ***P < .001.