The article that is often cited by Eisenberg and colleagues is an excellent summary of the research science into autoimmunity and endometriosis. What it concludes is that there is indeed co-existence of endometriosis and other autoimmune diseases (such as SLE, rheumatoid arthritis and autoimmune thyroid disease), however this may simply be due to the fact that endometriosis affects 1:10 women and the co existence of the two issues are by chance alone. To date, the evidence falls short for saying that endometriosis is autoimmune.
What is clear is that there is a complex interplay in the bodies defence mechanisms for preventing endometrial like cells implanting outside of the endometrium and causing inflammatory lesions and their sequelae, the exact role that the bodies own immune system has in this process is unknown. Just as it is too simplistic to think that retrograde menstruation is responsible for all endometriosis (and it is clear that this is not the sole cause), the role of the immune system and endometriosis is not yet understood. It is particularly important that this article notes that unlike other autoimmune diseases, endometriosis does not have a measurable autoantibody and does not respond to any known treatments for autoimmunity.
There have been studies done with existing drugs (anti TNF and pentoxifylline) that show no change in symptoms. Given that hormones drive endometriosis and changes in hormone profile may treat some women with endometriosis, any autoimmune treatments would have to be compared with these for side effects and their impact on a woman’s symptoms. No such studies have yet been undertaken.
So, to date there is no evidence that endometriosis has an autoimmune basis, with no auto antibody identifiable and the lack of response to existing treatments that have shown substantial benefits in other true autoimmune diseases. This also means that drugs such as steroids (such as prednisone) and methotrexate that are used for autoimmunity will not be beneficial for women with endometriosis. It is true we do not yet have all the answers in this field and ongoing research is important to try and define the exact role that the immune system has on and with endometriosis.
If only we had all the answers, so let’s continue to study and participate in research into this formidable opponent that is endometriosis.
Associate Professor Jason Abbott
Medical Director Endometriosis Australia