Objective: To investigate the presence of autoantibodies directed to corpus luteum (CoL) in systemic lupus erythematosus (SLE) sera and its correlation with menstrual disturbances.
Methods: We evaluated 87 female patients with SLE, < 40 years old, and 23 women with normal menses as controls. Anti-corpus luteum antibody was detected by immunoblot technique.
Results: Reactivity to a bovine CoL antigen was found in 22% of SLE sera. Characterization of the target antigen revealed a 67 kDa glycoprotein highly enriched in corpus luteum, but nearly absent in total ovary extract. Similarly, target antigen was also weakly detectable in tissues that produce or metabolize steroids, such as testis, adrenal cortex, and liver, and it was absent in adrenal medulla or HEp-2 cells. Anti-CoL antibody was easily distinguished from other frequent reactivities of SLE sera, including anti-RNP, anti-Sm, anti-Ro/La, anti-dsDNA, or anticardiolipin. The observation of anti-67 kDa reactivity to human CoL suggests a possible pathogenic role in gonadal dysfunction. Indeed, we observed an inverse association of anti-CoL antibody with the duration of hypergonadotropic amenorrhea. Supporting this hypothesis, in patients with normal or irregular menses, the presence of this antibody was associated with elevated serum level of follicle stimulating hormone, an early and specific sign of ovarian lesion.
Conclusion: Anti-CoL antibody seems to be associated with early stages of ovarian dysfunction in SLE. Moreover, since similar association of antiovarian antibodies has been observed in an experimental model of autoimmune oophoritis, our findings raise the possibility of autoimmune ovarian lesion in patients with SLE.