Research Uncovers New Connection Between Autoimmune Abnormalities and Infertility

University of Colorado Advanced Reproductive Medicine study found that an immune checkpoint is at work in ovaries, including within eggs.

DENVER, October 16, 2019 –A team of researchers from CU Advanced Reproductive Medicine, CU Anschutz Medical Campus and Yale University have found a new connection between the immune system and difficulties becoming pregnant. Abnormal function of an immune checkpoint may be involved in infertility.

The findings were just presented at the American Society for Reproductive Medicine Scientific Congress & Expo in Philadelphia. The researchers said they are now testing whether inappropriate signaling by the Programmed Cell Death Protein-1 (PD-1) pathway contributes to autoimmune problems in the ovaries of some women.

The efforts could prove promising for women with unexplained infertility, a diagnosis that finds no specific cause for infertility. This occurs in up to 30% of infertility cases.

Autoimmunity occurs when the body experiences improper immune reactions, and immune cells can sometimes attack healthy cells. The 2018 Nobel Prize in Medicine was awarded for the discovery of immune checkpoints that act to “dial down” normal immune reactions and help to minimize autoimmune reactions.

Autoimmunity has been detected in some women who are having difficulty conceiving. This research team has demonstrated that proteins found in immune checkpoints are present in the ovaries and fallopian tubes. To their surprise, PD-1 was found in egg cells and other cells that are directly involved in fertility.

“Signs of autoimmunity have been noted for many years in certain infertility cases. If immune checkpoints like PD-1 are not functioning properly to dampen immune reactions, fertility may be compromised,” said the study’s lead researcher Dr. Josh Johnson, of CU Advanced Reproductive Medicine.

“More study is necessary, but unexplained infertility may have more in common with certain autoimmune disorders than has been appreciated.”

The study examined the ovaries, oviduct tissue and follicular fluid from pre- and post-menopausal women. Other CU ARM researchers were involved in the study, including Dr. Alex Polotsky and Dr. Liesl Nel-Themaat.

About University of Colorado Advanced Reproductive Medicine

University of Colorado Advanced Reproductive Medicine specializes in the evaluation and treatment of infertility and reproductive disorders. The clinic is located at 3055 Roslyn St., Room 230, Denver, Colorado, with surgery and lab facilities at the University of Colorado Hospital in Aurora, Colorado. A Colorado Springs office is located at 4125 Briargate Parkway, #350. For more information, see