Stimulation of anti-RNP antibody binding to cultured keratinocytes by estradiol.

Antibodies to extractable nuclear antigens (ENA) are frequently demonstrated in the serum of patients with cutaneous lupus erythematosus. To gain a better understanding of the influence of sex hormones on cutaneous lupus, we investigated the in vitro binding of anti-ENA antibodies to cultured human keratinocytes. Estradiol-beta augmented the binding of anti-RNP, anti-SS-A/Ro, and anti-SS-B/La antibodies to cultured cells, but produced no enhancement of the binding of anti-Sm antibodies. In addition, we examined the effects of 16-alpha-hydroxyestrone, a highly estrogenic metabolite, on the binding of anti-ENA antibodies to cultured cells. This agent did not produce any augmentation of binding. Based on these experiments, we discuss the influence of estradiol on cutaneous lupus.