Study of MAIT Cells Suggests Biomarker for Type 1 Diabetes

Advances in type 1 diabetes (T1D) aren’t just in treatment and better management tools—scientists have also been looking for ways to prevent the disease.

While it is known that T1D is an autoimmune disease with both genetic and environmental triggers, researchers have been looking for a biomarker—a biological signal that would tip off who was at risk of beta cell destruction in the pancreas, which leaves the body unable to produce its own insulin.

Researchers in France, at CNRS (Centre Nationnal de la Recherche Scientifique) and Paris University, have discovered that just before the onset of T1D, the body experiences changes in cells known as MAIT lymphocytes (mucosal associated invariant T cells). MAIT cells are part of the immune system and are activated by gut microbiota, and the French researchers examined the connection between the MAIT cells and the disturbances of gut flora as they relate to T1D.

The results were published Monday in the journal Nature Immunology.

The investigations included an examination of both animal models, led by Agnes Lehuen, as well studies of blood samples taken from patients in Necker-Enfants Malades Hospital. Both showed changes in the MAIT cells just before T1D develops.

When T1D is diagnosed in children, they had fewer MAIT cells in their blood than found in children without diabetes. The study teams observed that pancreatic MAIT cells swelled in diabetic mice who were not obese, suggesting that when the missing MAIT cells in the diagnosed children had migrated to the inflamed pancreatic tissue.

According to a statement from the study team, “Experiments performed by the researchers on human cells in vitro and on (nonobese diabetic) mice suggest MAIT cells are directly linked to the destruction of pancreatic beta cells.”

The studies uncovered 2 qualities about the function of the MAIT cells in patients who develop T1D that may suggest their future value as a biomarker:

• First, it appears some defect is at work in the MAIT cells of patients who develop T1D that is tied to whatever disturbance in the gut bacteria that triggers the autoimmune response. This defect makes the gut bacteria vulnerable to bacteria that sets everything in motion.
• Second, the changes in the MAIT cells serve as an early warning system that make the cells a potential biomarker, pending further study.

Reference

Rouxel O, Da silva J, Beaudoin L, et al. Cytotoxic and regulatory roles of mucosal-associated invariant T cells in type 1 diabetes [published October 9. 2017]. Nat Immunol. doi:1 0.1038/ni.3854.