Studies in animal models of SLE have also shown the relevance of sex hormones for the development and course of SLE. Studies in the NZB/W F1 hybrid mouse support the role for female hormones in the modulation of autoantibody production, development of renal disease, and death (13). Female NZB/W F1 mice have higher autoantibodies titers and die several months earlier than males. Treatment with androgens improves the survival and reduces immune-complex deposits and development of renal disease in NZB/W F1 females (14). Prepubertal castration of NZB/W F1 males plus administration of exogenous estrogen causes a female pattern of lupus (15).