A 20-year-old male presented to the OPD with recurrent episodes of lower backache which was more in morning and relieved on movement. Patient gave history of multiple episodes of chest infections in the past for which the patient was hospitalized multiple times. On ophthalmoscopic examination, iritis and conjunctivitis were noted. Lab findings revealed HLA-B27 positivity, elevated CRP and elevated ESR. The doctor ordered the x-ray of the lumbar spine and performed a test. Which of the following interleukins is most commonly involved in the pathogenesis of the above disease: -
High-Yield Explanation
This is a case of Ankylosing spondylitis. X ray spine shows the classical bamboo spine appearance/ squaring of veebra. The test being performed is the Modified Schober's test. The pathogenesis of AS is immune-mediated. Tumor necrosis factor a (TNF-a) or IL-17A play a central role in the immunopathogenesis of AS. Mast cells and neutrophils are major IL-17-producing cells in peripheral ahritis Neutrophils producing IL-17 are prominent in apophyseal joints.