Suppressor immune cells: friends or foes?

Regulatory T (Treg) cells, which are essential to prevent catastrophic autoimmunity in mice and humans, can in some cases convert into inflammatory T cells capable of exacerbating autoimmunity. The findings, published online this week in Nature Immunology, lengthen the known list of immune cell types that are capable of promoting autoimmune disease.

The intracellular protein Foxp3 is essential for Treg cell development and function. Jeff Bluestone and co-workers found that, especially in inflamed tissues undergoing autoimmune attack, Treg cells can lose Foxp3 expression.

The resulting 'exFoxp3' cells released pro-inflammatory mediators and could trigger autoimmune type 1 diabetes.