Anti-oestrogen Antibodies in Users of Oral Contraceptives and in Patients with Systemic Lupus Erythematosus

Recent studies have demonstrated that many patients with SLE have elevated plasma levels of the minor oestrogen metabolite 16 alpha-hydroxyestrone (16 alpha OHE). This oestrogen is unique in its ability to react with lysine residues and form stable, covalent Heyns products with proteins. Increased levels of 16 alpha OHE-modified proteins have been found to occur on the membranes of red cells and lymphocytes in patients with SLE. In the present study, patient and control sera were analysed for the presence of circulating immunoglobulins which react with an oestrogen hapten. Anti-oestrogen antibodies were detected in 26% (9/34) of male and female SLE patients, and were found to correlate both with levels of plasma 16 alpha OHE (P less than 0.001) and with the presence of active disease (P less than 0.005). Surprisingly, this antibody activity was also observed in 25% (13/52) of normal, disease-free women who had a history of oral contraceptive use. No detectable activity was observed in normal men, women who had not taken oral contraceptives, or patients with a variety of other immunological diseases. The possible role of anti-oestrogen antibodies in both the hormonal exacerbation of SLE and in the long-term sequelae of oral contraceptive usage is discussed.