The percentage and CXCR3 phenotype of peripheral blood FoxP3⁺ Tregs is not altered in patients with cGVHD. Shown is CXCR3 expression by regulatory CD4⁺ T cells in the peripheral blood of patients after allogeneic SCT. Shown are the results of representative flow cytometric staining of FoxP3⁺ CD4⁺ Tregs (n = 5; A) and CXCR3⁺ Tregs (n = 5; B). Peripheral blood was analyzed for surface expression of CD3-APC-Cy7 and CD4-FITC and for intracellular FoxP3-PE to determine frequencies of CD4⁺ Tregs, and for their surface expression of the chemokine receptor CXCR3-PerCPCy5.5 (n = 5). Figures show the mean frequency of CD4⁺ FoxP3⁺ Tregs (C) and of CXCR3-expressing Tregs in control SCT patients and in SCT patients with cGVHD (D). Data are shown as the mean frequency of CD4⁺ T cells expressing FoxP3 and of FoxP3⁺ cells expressing CXCR3. Bars indicate SEM. *P < .05 by the Mann-Whitney U test.