Function of cTFH subsets and relative distribution after HSCT. (A) IgM production by naive B cells (IgD⁺CD27⁻) after in vitro coculture with different subsets of cTFH (CXCR5⁺) and non-TFH (CXCR5⁻) cells. (B) IgG production by naive B cells (IgD⁺CD27⁻) after in vitro coculture with different subsets of cTFH (CXCR5⁺) and non-TFH (CXCR5⁻) cells. N = 3. Graphs represent mean and standard deviation (SD). (C) Ratio of (Th2+Th17)/Th1 cTFH subsets in different patient groups. Black bars represent median values for each group. (D) Whisker plots represent frequency of Th1 (blue) and Th17 (red) cTFH subsets in patients with different severity of cGVHD. Exact Wilcoxon rank-sum test was used. ns, not significant; *P < .05; **P < 10⁻⁴.