SYK inhibition with R406 abrogates BCR-driven proliferation and survival of B cells from patients with cGVHD. Peripheral B cells from patients without cGVHD (grey bars) and with cGVHD (white bars) treated as indicated for 6 days. [Percent change = (V2 – V1) / V1 *100]. Data are median +/- range, pooled from 3 independent experiments. n = 4 / phenotype. One-Way ANOVA, p = 0.0002. Tukey's Post Hoc, * p < 0.05, ** p < 0.005, *** p <0.0005.