Differential effects of sex hormones on autoantibody production and proteinuria in chronic graft‐versus‐host disease‐induced experimental lupus nephritis
In patients with systemic lupus erythematosus, the female‐to‐male ratio is as high as 10:1. Sex hormones are thought to play a role in this difference in susceptibility. In a previous study, we demonstrated a high susceptibility of female mice to the development of glomerulonephritis after induction of chronic graft‐versus‐host disease (GVHD), compared with male mice. In order to unravel further this gender‐related difference (C57Bl/10*DBA/2)F1 hybrid mice were either castrated or ovariectomized and treated with 17β‐ethinyloestradiol or testosterone‐decanoate preceding the induction of chronic GVHD. Testosterone‐decanoate reduced significantly the development of albuminuria in females. In contrast, proteinuria of 17β‐ethinyloestradiol‐treated female mice was in the same range as that of sham‐operated mice. Autoantibody levels against glomerular basement membrane, renal tubular epithelium, dsDNA and ssDNA, as determined by ELISA, were higher in 17β‐ethinyloestradiol‐treated female mice than in all other groups. Immunofluorescence studies showed the presence of immunoglobulin and complement deposits in glomeruli of all animals, without significant differences between the experimental groups. Our findings confirm earlier observations, in that testosterone‐decanoate is shown to be an inhibitory compound, whereas 17β‐ethinyloestradiol has stimulating properties in autoimmunity. Moreover, our results show for the first time differential hormonal effects on autoantibody levels and proteinuria in experimental lupus nephritis.