Immunoregulatory gene expression. (A) Gene expression in CD4⁺CD25⁺ subpopulation. A representative experiment (1 of 3) is illustrated. Foxp3 (B), CD25 (C), CTLA-4 (D), GITR (E), PD-1 (F), and TGF-β (G) gene expression from peripheral blood mononuclear cells (PBMCs) of patients with alloGVHD (n = 28) and patients evaluated at the onset of autoGVHD (n = 16). The results include patients without clinical manifestations of alloGVHD (n = 8), patients without autoGVHD (n = 23), or non-CsA-treated autoBMT patients (n = 6). Expression of Foxp3 mRNA transcripts in CD8⁺ T cells was approximately 20-fold lower compared with the CD4⁺ T-cell subset. Expression of Foxp3 was not detected in the CD8⁺CD25^- subset. Expression of other markers was similar both in the CD25^- and CD25⁺ fractions of CD4⁺ T cells. BMT indicates bone marrow transplantation; CsA, cyclosporine A; CTLA-4, cytotoxic T lymphocyte-associated antigen-4; GITR, glucocorticoid-induced tumor necrosis factor receptor; PD-1, programmed death-1; TGF, transforming growth factor. Error bars indicate SEM.