Lupus susceptibility gene controls the development, stability, and function of regulatory T cells via expression.

The maintenance of regulatory T (T) cells critically prevents autoimmunity. Pre-B cell leukemia transcription factor 1 () variants are associated with lupus susceptibility, particularly through the expression of a dominant negative isoform in CD4 T cells. overexpression impaired T cell homeostasis and promoted inflammatory CD4 T cells. Here, we showed a high expression of in human and murine T cells, which is decreased in lupus patients and mice. deficiency or overexpression reduced the number, stability, and suppressive activity of T cells, which increased murine responses to immunization and autoimmune induction. Mechanistically, deficiency altered the expression of genes implicated in cell cycle and apoptosis in T cells. Intriguingly, , a Rho-GTPase previously associated with T homeostasis, was directly transactivated by Pbx1. Our results suggest that the maintenance of T cell homeostasis and stability by through cell cycle progression prevent the expansion of inflammatory T cells that otherwise exacerbates lupus progression in the hosts.