Discovery of Th22 cells may help in developing effective therapies for chronic skin and respiratory diseases

The newly discovered Th22 cells are a previously unknown subset of T helper cells. T helper cells are white blood cells that help activate other immune cells when the body is infected by viruses or bacteria. At the same time they help the body to tolerate own tissue and to prevent or curb inflammation.

The researchers of Helmholtz Zentrum München and the Center of Allergy and Environment (ZAUM) of Technische Universität München, together with their colleagues from London and Rome, discovered the Th22 cells while analyzing skin samples of patients with psoriasis, atopic eczema and allergic contact dermatitis. "During the histological examination we noticed T cells that were primarily characterized by the signaling molecule interleukin-22 (IL-22)," explained Dr. Stefanie Eyerich, the lead author of the study.

Th22 cells aid in tissue repair. At the same time they warn our skin cells of impending environmental dangers and stimulate the skin cells to protect themselves. In addition, they can help to strengthen the barriers of the skin and possibly also of the lung by stimulating cells to produce more collagen.

Dr. Carsten Schmidt-Weber of Imperial College London and coordinator of the study said: "We are seeing an increase in chronic diseases like skin and respiratory diseases. Besides genetic disposition, the causes are higher hygienic standards and modern nutritional habits. Diseases like psoriasis can have a substantial negative impact on a patient's quality of life, and sufferers must often follow long, drawn-out skin care treatment regimens to keep their symptoms at bay."

"We consider the discovery of the Th22 cells to be a milestone in immunology, providing a new starting point for the future treatment of chronic inflammatory diseases such as eczema, scleroderma, asthma or COPD," explained Professor Heidrun Behrendt, director of ZAUM and the Clinical Cooperation Group of Helmholtz Zentrum München and TU München.

The Munich researchers and their colleagues are elucidating the genesis of Th22 cells and investigating Th22-specific genes, which shall contribute to the development of selective and effective therapies for patients with chronic skin and respiratory diseases. Like other T helper cells, Th22 cells belong to a part of the immune system which can recognize damaging pathogens even after a long time has passed. This means that each treatment targeting these cells would have a potential long-term effect.