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Study finds causes of psoriasis

Important step for the cause research of psoriasis
What exactly causes psoriasis (med. Psoriasis) is not fully understood. Experts believe that several factors interact and that in addition to a genetic predisposition the immune system plays a central role. Now, researchers at the Ludwig Maximilian University of Munich (LMU) have apparently taken a big step forward in root cause research. They realized that the immune system attacks certain pigment cells and thereby causes inflammation. The findings could contribute to the future use of new forms of treatment against the unpleasant skin disease.

Those affected suffer from scaly skin and heavy itching
Millions of people worldwide suffer from the inflammatory chronic skin disease psoriasis (psoriasis), which is characterized by silvery-scaly, sometimes large-scale deposits on the skin (plaques). These ignite and lead to strong itching, an unpleasant feeling of tightness and pain. Frequently, only single skin lesions occur on the elbow or the scalp, but also the nails or, in particularly severe cases, the joints (psoriatic arthritis) may be affected.

The cause of psoriasis remained unclear for decades, now researchers seems a significant step closer to the solution. (Image: lipowski / fotolia.com)

So far, the exact causes for the development of psoriasis could not be clarified. However, it is assumed that it is a multifactorial disease and that in addition to a genetic predisposition, the immune system plays a central role. As the German skin and allergy help e.V. reports, a variety of scientific findings would indicate that psoriasis is an autoimmune disease in which the immune system is mistakenly directed against the body's own cells.

Munich researchers discover the mechanism of autoimmune disease
Now scientists of the LMU-Klinikum could apparently bring a little more light into the dark. As the hospital reports, it was possible to elucidate the mechanism of this autoimmune disease. "We have demonstrated for the first time that psoriasis is based on an autoimmune reaction against the pigment-forming cells of the skin," said Jörg Prinz from the Department of Dermatology and Allergology at the LMU University Hospital. According to the prince, this explains "the skin-specific nature of psoriasis, as these melanocytes predominantly occur in the skin." It is hoped that the researchers' findings will be incorporated into the development of new drugs in the medium and long term, the dermatologist continues.

Scientists have long been on the trail of the causes of the disease
According to the information from the hospital, according to current data, in Germany alone, two million people are receiving medical treatment every year for psoriasis. Once the inflammatory skin changes "break out", they often occur in many people affected. Experts believe that a certain group of white blood cells (called "T cells"), which are part of the body's defense system, attack cells of the skin and trigger inflammation.

So far, however, it has remained unclear which cells are actually being attacked, and scientists continue to puzzle over how the disease mechanisms of T-cell-mediated autoimmune diseases (such as rheumatism) can generally be explained. The fact that it is the pigment-forming cells that are the victims of T cells, the LMU researchers would have recognized by "tricky, multi-year experiments" with human psoriatic skin tissue - and not, as usual in medical research, on the basis of animal experiments, supplements the hospital.

In addition, the team led by Jörg Prinz and Klaus Dornmair also succeeded in largely elucidating the complex mechanism of the disease. Previously, it was already known that in the cells of people with an increased risk of psoriasis certain variants (alleles) of certain genes found. The main risk gene for psoriasis bears the name "HLA-C * 06: 02" and belongs to the so-called "HLA genes".

Unexpected activity path discovered
These in turn would encode the assembly instructions for HLA molecules, which are located on the surface of all cells and present to the T cells parts of pathogens, informed the LMU-Klinikum. The T cells would then identify the pathogen and initiate a corresponding defense response against it. However, according to the Munich researchers HLA-C * 06: 02 present parts of molecules that are produced by the pigment cells themselves and recognized by the T cells. According to Jörg Prinz, this shows a "completely unknown and unexpected autoimmune activation pathway in psoriasis", which in the view of the scientist represents a "pioneering discovery".

The finding that psoriasis is a T-cell-mediated autoimmune reaction against melanocytes offers patients "a rationale for explaining their clinical picture for the first time," said Prinz. As a result, it is to be hoped that the perception of the disease will change as well and minimize the associated uncertainties and negative behavior of outsiders. "This should greatly improve the social acceptance and personal self-perception of patients with psoriasis," emphasizes Prinz. (No)