The role of sctla-4 in pathogenesis of ankylosing spondylitis and evaluation of its relation with clinical manifestations

Aim and Hypothesis: Ankylosing Spondylitis (AS) is characterized by abnormal immune responses including T cell activation. Although Cytotoxic T lymphocyte associated molecule-4 (CTLA-4) is involved in down-regulating immune responses, a soluble form of CTLA-4 (sCTLA-4) has been identified and was found at high levels in several autoimmune diseases. We aimed to determine the relation between the serum levels of sCTLA-4 and AS disease activity. Methods: In this work, 38 AS patients, 28 RA patients and 27 healthy controls were studied. sCTLA-4 cytokine level for each patient was determined with the ELISA method. ESR, CRP and demographic characteristics were recorded for each patient group. Obtained experimental data were statistically compared. Results: Compared to the RA group and healthy controls, high levels of sCTLA-4 were found in the AS group (p<0,001). Soluble CTLA-4 serum levels were not correlated with the clinical index of disease activity (p=0,370). A correlation was noted between the serum levels of ESH and BASDAI for the AS group (p=0,012). Conclusion: Our study investigates the role of sCTLA-4 levels in the pathogenesis of AS, and establishes a statistically meaningful difference between the serum levels of sCTLA-4 in AS patients, and those in RA patients and healthy controls (p<0,001). Early diagnosis is important in AS patients, and disease-spesific diagnostic tests are required for this purpose. Consequently, further research is needed to explore the relation between cytokine levels and clinical findings for the early-stage AS patients. While a meaningful relation was not observed between the sCTLA-4 levels and the disease activity in AS patients, nevertheless, these cytokine levels can be used for the early diagnosis of AS. Key words: sCTLA-4, cytokine, Ankylosing Sponylitis