La Marca A1, Brozzetti A, Sighinolfi G, Marzotti S, Volpe A, Falorni A. Abstract PURPOSE OF REVIEW: To review the pathogenesis of premature ovarian insufficiency due to steroid cell autoimmunity (SCA-POI). RECENT FINDINGS: Autoimmune oophoritis is characterized by a selective mononuclear cell infiltration into the theca layer of large, antral follicles, with earlier stage follicles consistently free of lymphocytic infiltration. SCA-POI is caused by the selective autoimmune destruction of theca cells with preservation of granulosa cells that produce low amounts of estradiol because of lack of substrates. Typically, serum concentrations of inhibins are increased in women with SCA-POI, as compared to both healthy fertile women and women with other forms of ovarian insufficiency. Normal serum antimüllerian hormone (AMH) concentrations were detected in two-thirds of women with recently diagnosed SCA-POI, which demonstrates that this form of ovarian insufficiency is associated with a preserved pool of functioning follicles. SUMMARY: The combined measurement of autoantibodies and markers of ovarian reserve (as inhibin B and AMH) may permit to identify women with POI due to steroid cell autoimmunity with a preserved proportion of primordial and primary follicles. In the future the development of techniques of in-vitro folliculogenesis may permit new treatment strategies for women with SCA-POI-related infertility.