Two separate effects contribute to regulatory T cell defect in systemic lupus erythematosus patients and their unaffected relatives

Summary Forkhead box P3 (FoxP3)+ regulatory T cells (Tregs) are functionally deficient in systemic lupus erythematosus (SLE), characterized by reduced surface CD25 [the interleukin (IL)-2 receptor alpha chain]. Low-dose IL-2 therapy is a promising current approach to correct this defect. To elucidate the origins of the SLE Treg phenotype, we studied its role through developmentally defined regulatory T cell (Treg) subsets in 45 SLE patients, 103...