Scientists have identified why only certain people with psoriasis develop painful joint inflammation. About 20–30% of people with psoriasis go on to develop a more severe condition called psoriatic arthritis, a painful form of joint inflammation that can progress silently and, if untreated, cause lasting damage to bones and joints.
Researchers have long tried to understand why only some patients progress from skin symptoms to joint disease. Now, a team from the Department of Medicine 3 – Rheumatology and Immunology at Uniklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), reports identifying the immune cells that migrate from inflamed skin to the joints, where they trigger inflammation.
Published in Nature Immunology, the findings suggest potential ways to prevent psoriatic arthritis before it fully develops.
How inflammatory cells move from the skin to the joints
The researchers discovered that psoriasis promotes the development of specialized immune precursor cells in the affected skin. According to Dr. Simon Rauber, head of the working group at the Department of Medicine, these cells can move from the skin into the bloodstream and then on to the joints. He also noted that simply entering the joint is not enough to cause inflammation.
How inflammatory cells enter the joint
To understand what triggers a flare, the researchers examined the joint environment itself. When immune cells arrive in the joint, they encounter fibroblasts—connective tissue cells that normally help maintain and protect joint tissue—but these cells react poorly to the incoming immune cells.
According to Prof. Dr. Andreas Ramming, team leader and deputy head of Department Medicine 3, the protective function of these cells is often weakened in people who develop psoriatic arthritis. As a result, the body fails to effectively control the invading inflammatory cells, and they instead trigger inflammation within the joint. These findings help explain why only some people with psoriasis go on to develop joint disease.
Detecting and preventing the disease early, before it reaches the joints
Because doctors can already detect these migratory immune cells in the blood before joint inflammation begins, they may use them as an early warning marker in the future, allowing clinicians to identify at-risk patients sooner. Treatment strategies could then focus on targeting these cells to stop them from triggering inflammation in the joints.
Read the original article on: SciTechDaily
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