Scientists have pinpointed the specific immune cells that explain why psoriasis can progress into psoriatic arthritis. They discovered that these cells develop in the inflamed skin of psoriasis patients before moving into the bloodstream and traveling to the joints.

According to the study, the presence of these cells in the joints does not automatically lead to inflammation. Instead, joint inflammation occurs only when the protective barrier of the connective tissue cells inside the joint weakens. This failure allows the traveling immune cells to step in and trigger a painful reaction. The researchers believe these migratory cells can be detected in the blood at an early stage, which could lead to new ways to identify and prevent the disease before it starts.