Fostamatinib has little clinical therapeutic benefit in a B10.D2 into BALB/c sclerodermatous cGVHD model but decreases expression of CXCR4 on CD11b⁺ and CD4⁺ cells. (A) Clinical GVHD scores or (B) skin GVHD scores in vehicle-treated (gray squares) or R788-treated (black circles) mice in the B10.D2 into BALB/c model. (C) Frequency of viable CD11b⁺ cells. (D) Expression of CXCR4 on CD11b⁺ cells. (E) Absolute number CD19⁺ B cells. (F) Expression of CXCR4 on B cells. (G) Expression of CXCR4 on CD4⁺ cells. *P < .5. Error bars represent SEM; n = 5 per group. CLN, cervical lymph node; MLN, mesenteric lymph node.