Antiphospholipid Syndrome (APS), an autoimmune disorder that causes an increased rate of blood clotting, is responsible for most recurrent miscarriages. It is also the most common cause of stroke and heart attacks in young women. Treatment usually consists of heparin or aspirin to prevent blood clots.

Yale University researchers have found that the actual cause of this disorder is a common gut microbe, Roseburia intestinalis. A healthy gut microbiome has great diversity, but certain bacterial strains can cause problems when they produce a chemical imbalance. Our gut microbes are responsible for producing neurotransmitters, hormones, vitamins, and proteins involved in blood clotting. In patients with a genetic predisposition to APS, the immune system's T and B lymphocytes respond to a protein involved in clotting and also to the bacteria as well as certain amino acids found in the bacteria. Over time, this process leads to tissue damage and persistent symptoms. Treatments that address the microbial cause rather than the immune system offer promise.

The gut's many microorganisms, the microbiota, have their own genes, which are referred to as the gut microbiome. Imbalances in the gut microbiome are suspected of contributing to several different autoimmune disorders including multiple sclerosis (MS). In patients with MS, fecal microbe transplants are being experimentally in clinical trials.

Resource: Kashef, Ziba. "How Common Gut Bacteria Trigger a Lethal Autoimmune Disease." Yale News June 18, 2019

https://news.yale.edu/2019/06/18/how-common-gut-bacteria-trigger-lethal-autoimmune-disease