Common bacteria that reside in the human gut may be partly to blame for a serious autoimmune disease called antiphospholipid syndrome that frequently affects young women, report researchers.
For their study, the research team focused on cells from patients with the immune system disorder, which raises the risk of blood clots. This chronic condition can lead to lung clots, strokes, heart attacks, and in pregnant women, miscarriages or stillbirths.
Using patient immune cells and antibodies, as well as animal models of the disease, the investigators did several experiments to explore the phenomenon. They found that a common gut bacterium, Roseburia intestinalis, can trigger antiphospholipid syndrome in individuals who have a genetic predisposition.
In those patients, the immune system’s defender T and B cells react to a blood protein involved in clotting, and also to the bacteria, in certain amino acids found in the bacteria. Over time, this ongoing “cross-reactive” response leads to tissue damage and chronic disease.
By identifying a gut bacterium, instead of the immune system, as the target for treatment, the study could lead to new drugs for these patients, according to the scientists.
The research was also the first to show cross-reactivity of gut bacteria in humans with this disease, says senior author Martin Kriegel, assistant professor of immunobiology and of medicine (rheumatology) at the Yale University School of Medicine—a finding that could impact the understanding and treatment of other autoimmune diseases.
The study appears in Cell Host & Microbe. The National Institutes of Health, Yale Rheumatic Diseases Research Core, Women’s Health Research at Yale, O’Brien Center at Yale, Arthritis National Research Foundation, Arthritis Foundation, and Lupus Research Alliance, as well as the American Heart Association and Lupus Research Institute, supported the research.
Source: Yale University