In this review we discuss how sex steroids and prolactin affect regulation and responsiveness of B and T cells. Sex hormones exert profound effects on several physiological processes of nonreproductive tissues. In the immune system, several studies with experimental models for SLE have shown a noticeable pro-inflammatory role for ERα, contributing to disease development reflected in proteinuria and renal pathology. On the other hand, ERβ appears to have an antiinflammatory and immunosuppressive effect. Estrogen/ERα signaling induced an increase of Th17 cells in lymph nodes as well as the expression ...