Levels of the Immune Cytokine Interleukin 37 Raised in Endometriosis

Levels of the Immune Cytokine Interleukin 37 Raised in Endometriosis

A new study published last week in the Reproductive Sciences journal, entitled “Increased Expression of Interleukin 37 in the Eutopic and Ectopic Endometrium of Patients With Ovarian Endometriosis” is giving new insights into the causes and processes involved in this challenging disease. Endometriosis is a very frequent condition affecting as much as 10% of reproductive-age women and is caused when cells from the inner lining of the uterus (endometrium) begin to grow outside the uterus, usually in the pelvic cavity in the abdomen. The inflammation is caused by the detachment of cells from the wrong site during menstruation and is thought to be responsible for its symptoms, usually infertility, pelvic pain, painful menstruation and painful sexual intercourse.

Nevertheless, not only is endometriosis is difficult to diagnose, often requiring surgery for the confirmation of diagnosis, but also its causes and natural history are poorly understood. In this study, a team of researchers from the Peking Union Medical College Hospital, China, has looked into the effects of the immune system in endometriosis from a novel perspective.

Specifically, the study led by Dr. Jian-Fa Jiang investigated the differential expression of the interleukin (IL) 37 cytokine, a protein of a group of hormone-like substances that alters the function of the immune system when released. Contrary to most interleukin proteins that activate the immune system, IL-37 main function is to inhibit the immune system (i.e., anti-inflammatory effects) and its concentration is usually raised in various autoimmune and inflammatory diseases in an effort to control the hyper-activated immune system.

The scientists studied the expression of IL-37 in endometrium and endometriosis samples in affected patients (24 individuals) and compared them to endometrium from healthy women (15 individuals). They found that the IL-37 gene was highly expressed and that IL-37 levels were high in both samples from endometriosis patients when compared to women without endometriosis.

As the authors state in their report, “this study detected IL-37 mRNA and protein expression in the endometrium of women with ovarian endometriosis. (…) These results show that increased expression of IL-37 might be involved in the inflammatory process of endometriomas”.

A deep knowledge of the relationship between all these immune signals might be the key for novel therapeutic approaches in endometriosis.