Within the CD4+CD25highCD127low T cell population, 1,25(OH)2D3 or TX527 increased the expression of the Treg-associated molecule cytotoxic T lymphocyte antigen 4 (CTLA-4, CD152) in T cells of control subjects and patients with type 1 diabetes (Fig. 3C). This evidence concerns the gene CTLA4 and type 1 diabetes mellitus.