Background/Purpose: Familial Mediterranean Fever(FMF) is an autoinflammatory disease characterized by recurrent fever attacks, sterile peritonitis, pleural inflammation, arthritis and / or  erysipelas like rash. Prolidase is a specific imidodipeptidase that plays a role in collagen degradation. HIF-1α is an important protein in the regulation of immunological response, hemostasis, vascularization and anaerobic (oxygen-free) metabolism. Serum prolidase activity in patients with ankylosing spondylitis(AS) was statistically significantly lower than in the control and rheumatoid arthiritis(RA) groups.Prolidase activity was not significantly different in patients with RA compared to the control group. In patients with Behçet’s disease, prolidase activity was statistically significantly higher than in healthy control group.In FMF patients, the effect of prolidase enzyme is unknown.The aim of the study is to compare serum prolidase and HIF-1 α levels in patients with FMF in attack-free period and healthy control group.Methods: Between August 2017 and December 2017, sixty patients who diagnosed FMF according to the criteria of the tel- and sixty healthy volunteers were enrolled in the study. All of FMF patients were under traetment of colchicine (1-1.5mg). Clinical findings and PRAS scores of all patients and were recorded.Blood tests were examined by Elisa method. The study protocol was approved by the local ethics committee.Results: Laboratory findings and basic characteristics of FMF and healthy control group are shown in Table1. In this study, mean serum prolidase level was measured as 72.1 (25.1-114.9) ng/ml in FMF group and 30.7 (21.3-86.2) ng/ml in healthy control (HC) group (Figure 1). There was statistically significant difference between two groups (p=0.018). The mean serum levels of HIF-1α in the FMF group were measured as 482.0(292.0-3967.0) pg/ml and 632.0(362.0-927.0) pg/ml in the HC group. There was no statistically significant difference between the two groups (p<0.05). According to ROC analysis, optimal levels of serum prolidase (>54.03 ng/ml; sensitivity was 65% and specificity was 68.3%, p<0.05). There was no significant difference between serum prolidase and HIF-1α levels in the mild, moderate and severe patient groups according to PRAS score (p>0.05). There was no significant correlation between laboratory findings, sex, age, and prolidase (p>0.05, r<0.25).Conclusion: Serum prolidase enzyme levels in FMF patients with attack-free period were significantly higher than in the healthy control group. There was no significant difference between the two groups at HIF-1α level. High prolidase enzyme levels may be associated with clinical or subclinical inflammation in FMF patients. However, the role of prolidase and HIF1-α in the FMF disease needs to be clarified with more extensive and comprehensive studies.

The data are expressed as mean ± standard deviation, median (1th quarter-3th quarter) and n(%).