Endometriosis is a disease in which tissue resembling that which normally lines the uterus, called the endometrium, starts to grow elsewhere and form lesions. These lesions respond to hormonal cycles in the same way as endometrium in a woman’s uterus, and swell and shed during each menstrual cycle. But the lesions cannot be expelled like normal endometrium. This can lead to inflammation, severe pelvic pain, and infertility in women.

Several causes of endometriosis have been proposed, but no single cause has emerged as a clear trigger. It seems likely that a combination of factors may be responsible for the development of the disease.

The immune system

The immune system, in addition to protecting the body against disease and infections, works to eliminate foreign or abnormal cells in the body.

For example, the immune system will start to attack a newly transplanted organ, considering it foreign tissue. This is why people who undergo an organ transplant need to use immune suppressants for life. The immune system can also recognize and eliminate cells that are in the wrong place, including cells forming the endometrial lesions.

The immune system can start to mistakenly attack healthy tissues without a clear cause, leading to what are known as autoimmune diseases.

Endometriosis as an immune disease

In endometriosis, the immune system fails to recognize and target endometrial tissue growing elsewhere in the body. This failure may indicate that endometriosis is an immune disease.

Endometrial lesions themselves may have some ability to evade the immune response — much as some cancers do — by tricking or confusing immune cells that would otherwise attack those cells that form the lesions.

Interestingly, several studies have indicated that women with endometriosis are more likely to develop autoimmune diseases such as lupus, which may be an indication that the immune system is not working properly (impaired) in women with the disease.

Immune system and infertility

Some researchers think that infertility in endometriosis is strongly linked to aberrant immune mechanisms, especially the inflammatory response to endometrial lesions. They propose that the extreme inflammation in the abdomen surrounding endometrial lesions creates an environment that causes a hormonal imbalance, and leads to a type of chemical stress that can severely impact the viability of the egg, sperm, and embryo.


Endometriosis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.