We studied whether patients with systemic lupus erythematosus can have organ-specific antibodies directed against ovaries. With a recently developed enzyme-linked immunosorbent assay system that uses both a soluble and an extractable corpus luteum antigen fraction, we detected both IgG and IgM antibodies in the sera of patients with systemic lupus erythematosus (16 of 19, 84%). The highest levels of IgG antibodies were seen when the extractable organ fraction (ST80) was used as the antigen.