Potential New Treatment Option for Fatal Rare Disease

New research suggests that replacing missing gut bacteria and restoring the inosine metabolite could treat a rare autoimmune disease that affects the intestines, skin, and endocrine glands.

Regulatory T cells are designed to prevent the immune system from attacking the body’s own tissues and organs, however, defects in these cells can result in numerous autoimmune disorders. In these disorders, the immune system attacks various parts of the body, and often results in painful, disabling symptoms.

Defects in regulatory T cells can cause inflammation, as well as IPEX syndrome, by altering gut bacteria. IPEX syndrome is a rare disease that is life-threatening in children. Many patients with IPEX syndrome develop eczema, type 1 diabetes, and severe enteropathy. If these patients do not receive a stem cell transplant, they typically die before age 2.

Changes in the gut microbiome can also lead to multiple autoimmune disorders.

In a new study published by The Journal of Experimental Medicine, investigators discovered that mice carrying a mutated version of the Foxp3 gene displayed changes in their gut microbiome when they started to display autoimmune symptoms.

These mice models were seen to have lower levels of Lactobacillus bacterium. This family of bacteria is typically considered healthy, as it lives in multiple parts of the human body without causing diseases.

Treatment with this bacterium can effectively treat diarrhea, eczema, hayfever and other conditions, while also preventing diarrhea related to antibiotics, according to Medline Plus.

The investigators found that they were able to reset the gut microbiome by feeding the mice Lactobacillus reuteri, which resulted in reduced inflammation. This was also seen to extend survival as well, according to the study.

Bacteria living in the body secrete metabolites that can cause changes in a person’s health. The researchers also discovered that mice without Foxp3 lacked the inosine. However, the levels of the metabolite were restored after the mice were administered treatment with L. reuteri.

Through binding to a cell surface protein, adenosine A2A receptors, inosine is able to hinder the creation of pro-inflammatory Th1 and Th2 cells, according to the study.

High amounts of these cells were discovered to be present in mice models without Foxp3, but the levels were restored with L. reuteri or inosine treatment. This also leads to a reduction in inflammation and mortality.

Since there is currently no cure for the disease, patients must manage each symptom on its own. These findings could present a cure for these patients.

"Our findings suggest that probiotic L. reuteri, inosine, or other A2A receptor agonists could be used therapeutically to control T cell-mediated autoimmunity," concluded the study’s lead researcher Yuying Liu, PhD.