This is a fascinating question. Immune privilege can be thought of as antigens hidden away from the immune system by either physical (i.e. blood-brain barrier) or immunological barriers. Immunological barriers include low expression of MHC proteins, high balance between regulatory and effector cells or expression of protective molecules such as Fas or immune suppressive cytokines such as TGF-beta (as suggested as mechanisms of immune privilege in the anterior chamber of the eye). The reason that females are more susceptible to males for most classical autoimmune diseases, with exceptions being type 1 diabetes, myasthenia gravis, pemphigus vulgaris and Goodpasture's syndrome, is not clear. Some authors have suggested that women make stronger inflammatory responses to infectious agents than men because their survival is more important for continuance of the species. However, the detailed mechanism of this is not clear.

Thank you for replying. I found your answer really helpful. I find it curious that older women were particular targets for autoimmune disease in the context of immunosenescence.