Decreased expression levels of FOXP3 in patients with cGVHD. (A) Expression levels of the Treg-specific transcription factor FOXP3 was assessed by quantitative PCR in patient and donor samples, normalized, and reported as a function of total lymphocytes (AU, arbitrary units). Box plots define the values for median, range, 25th, and 75th percentiles. P values were calculated using the Wilcoxon rank-sum test; cGVHD versus no cGVHD, P = .009; cGVHD versus healthy donors, P = .01; no cGVHD versus healthy donors, P = .34. (B) Correlation between CD4⁺CD25⁺ phenotypic values and FOXP3 expression levels in patients with cGVHD was calculated using a rank-based Spearman test (P < .001; r_s = 0.60). (C) Patients with cGVHD were subdivided according to whether they previously developed aGVHD. Box plots define the values for median, range, 25th, and 75th percentiles. P values were calculated using the Wilcoxon rank-sum test; aGVHD and cGVHD versus no aGVHD and cGVHD, P = .29; aGVHD and cGVHD versus no aGVHD and no cGVHD, P < .001; no aGVHD and cGVHD versus no aGVHD and no cGVHD, P = .005.