BCR-driven phosphorylation of BLNK is increased in CD27⁺and CD27⁻B cells from patients with cGVHD. Phosphorylation of BLNK (tyrosine 84) and Syk (tyrosine 348) in CD27⁺ and CD27⁻ B cells (CD20⁺) stimulated with α-IgM (5 μg/mL) or PBS as a control as indicated for 5 minutes. (A) (Left) representative dot plots of pBLNK in CD27⁺ B cells from a patient (upper) without cGVHD (−cGVHD) and (lower) with cGVHD (+cGVHD). Numbers indicate frequency of CD20⁺ CD27⁺ B cells that are pBLNK⁺. (Right) Frequency of BLNK phosphorylation in CD27⁺ B cells quantified in patients without cGVHD (n = 6, open circles) and with cGVHD (n = 5, filled squares). Data are median ± range pooled from 2 independent experiments, *P < .05. (B) (Left) Representative dot plots of pBLNK in CD27⁻ B cells from a patient (upper) without cGVHD (−cGVHD) and (lower) with cGVHD (+cGVHD). Numbers indicate frequency of CD20⁺ CD27⁻ B cells that are pBLNK⁺. (Right) Frequency of BLNK phosphorylation in CD27⁻ B cells quantified in patients without cGVHD (n = 7, open circles) and with cGVHD (n = 6, filled squares). Data are median ± range pooled from 2 independent experiments, *P < .05. (C) (Left) Representative dot plots of pSyk in CD27⁺ B cells from a patient (upper) without cGVHD (−cGVHD) and (lower) with cGVHD (+cGVHD). Numbers indicate frequency of CD20⁺ CD27⁺ B cells that are pSyk+. (Right) Frequency of Syk phosphorylation in CD27⁺ B cells quantified in patients without cGVHD (n = 6, open circles) and with cGVHD (n = 5, filled squares). Data are median ± range pooled from 2 independent experiments, *P < .05. (D) (Left) Representative dot plots of pSyk in CD27⁻ B cells from a patient (upper) without cGVHD (−cGVHD) and (lower) with cGVHD (+cGVHD). Numbers indicate frequency of CD20⁺ CD27⁻ B cells that are pSyk⁺. (Right) Frequency of Syk phosphorylation in CD27⁻ B cells quantified in patients without cGVHD (n = 7, open circles) and with cGVHD (n = 6, filled squares). Data are median ± range pooled from 2 independent experiments, *P < .05.