Serum soluble fas ligand levels in familial Mediterranean fever

Introduction: Fas/FasL system plays an important role in the regulation of cell life and death, and circulating levels of sFasL have been shown to increase in some inflammatory conditions. However, there is no sufficient information about the levels of sFasL in patients with FMF. This study was designed to evaluate the serum sFasL levels in patients with FMF during attack and attack-free periods. Methods: Twenty-five FMF patients in attack and forty-four in free-attack period, and 20 age-, sex-, and BMI-matched healthy controls were included in this study. Participants with any chronic diseases were excluded. Blood samples were obtained within the first 24 h of the attack period and between febrile attacks, and levels of WBC, ESR, Fibrinogen, hsCRP and sFasL were determined. Results: The levels of traditional acute phase reactants during the attack were significantly higher than the attack-free and controls (p < 0.05). The serum sFasL levels in the FMF study groups did not differ from the control group (0.70 ± 0.08 vs. 0.73 ± 0.12; 0.70 ± 0.08 vs. 0.83 ± 0.14; 0.73 ± 0.12 vs. 0.83 ± 0.14, respectively, p > 0.05). Moreover, the sFasL levels during the attack were not significantly different from those in attack-free patients (0.70 ± 0.08 vs. 0.83 ± 0.14, p > 0.05). Conclusion: In this study, we demonstrated that serum sFasL levels were not markedly affected in FMF and cannot be used as a supportive marker to differentiate attacks from attack-free periods. However, further studies are needed to determine its usefulness as a marker in clinical practice.