Interleukin-17 bei chronisch-entzündlichen und autoimmunen erkrankungen. Rheumatoide arthritis, morbus Crohn und Wegener-granulomatose

Data from recent animal experiments and clinical studies show that interleukin-17 (IL-17A, B, C, D, E, and F) plays an important role as proinflammatory cytokine in the host response to extracellular bacteria and in chronic inflammatory and autoimmune diseases. These findings have led to a revision of the well-known T_H1/T_H2 hypothesis. In rheumatoid arthritis elevated IL-17 serum levels, Th-17 cells in synovial fluid and in T-cell-rich areas of inflamed synovia are found. In Wegener's granulomatosis, IL-17D is expressed in nasal granulomas. In Crohn's disease IL-17 as well as IL-17 plus IFN-γ producing CD4⁺ T-cells are detected in peripheral blood and inflamed intestinal mucosa. So far, CD4 ⁺IL-17⁺IFN-γ⁺ T-cells have been described only in humans. These and other findings indicate a number of differences in the cytokine response between murine models and human beings.