We investigated the effects of cyclosporin A (CyA) on the development of lupus dermatoses in autoimmune-prone MRL/Mp-lpr/lpr (MRL/lpr) mice. The MRL/lpr mouse is an animal model for the spontaneous development of skin lesions similar to those of human lupus erythematosus (LE). Virgin female MRL/lpr mice, at the age of 1 month were treated orally with CyA. CyA reduced the incidence and intensity of IgG immunofluorescence at the dermoepider-mal junction, the titre of serum anti-double-stranded DNA antibodies and lymphoproliferation. However, CyA did not improve the survival ratio, the incidence of skin lesions or lupus nephritis.