Abnormal cTFH values and CXCL13 levels in patients with active cGVHD. (A) Frequency of cTFH (CXCR5⁺CD45RA⁻ within CD4⁺ T cells) in healthy donors (HD), patients with no cGVHD, active cGVHD, and resolved cGVHD. (B) Absolute number of cTFH (CXCR5⁺CD45RA⁻CD4⁺ T cells) in the different clinical groups. (C) CXCL13 plasma concentration (pg/mL) was measured by ELISA and plotted for each patient group. Data were log₁₀ transformed. Black bar represents median value for each group. The Wilcoxon rank-sum test was used. *P < .05; **P < 10⁻⁴. ns, not significant.