Unlike other rheumatic diseases, acute phase reactants such as C-reactive protein and erythrocyte sedimentation rate are not diagnostic for patients with Spondyloarthropathies (SpA). Also, it is not possible to monitor disease activity with these tests. On the other hand, HLA-B27 positivity varies between races, and 8% of the normal population is HLA-B27 positive. In this manner, new biomarkers for endorsing the diagnosis and monitoring the disease activity are necessary. Acute phase reactants are not sensitive for diagnosing and assessing disease activity. This may lead to a diagnostic delay of up to 9 years. The investigators hypothesize that Raftlin-1, thought to have a regulatory role in TH17 function and IL-17-mediated immunity, may be a novel biomarker for showing inflammation-related clinical features.