Can Serum Fetuin-A Be Regarded as an Inflammatory Marker Among Patients with Familial Mediterranean Fever?

Familial Mediterranean fever (FMF), the most frequent periodic fever syndrome, is an autosomal recessive inherited disease that predominantly affects eastern Mediterranean populations. Fetuin-A is a well known negative acute-phase protein. Studies of this glycoprotein as a marker of inflammation in FMF are limited. We have investigated the relationship between serum levels of fetuin-A and inflammatory markers in patients with FMF before, during, and after FMF attacks. Sixty-seven patients with FMF were enrolled in this study. Serum fetuin-A, seruloplasmin, fibrinogen, C reactive protein (CRP), white blood cell count (WBC), calcium, and erythrocyte sedimentation rate (ESR) were measured three times: during the attack-free period, 12 h after FMF attacks, and 7 days after FMF attacks. Plasma fetuin-A concentration was measured by use of an enzyme-linked immunoassay (ELISA) kit. Correlations and differentiation between the serum fetuin-A and other inflammatory markers in patients with FMF were investigated by use of the paired-samples T test and the Pearson correlation test (p < 0.01). Serum fetuin-A levels of all FMF patients in the attack period were significantly lower than in the attack-free period (p < 0.001). In contrast, serum seruloplasmin (p < 0.05), fibrinogen (p < 0.001), CRP (p < 0.05), WBC (p < 0.05), and ESR (p < 0.05) were all significantly higher than in the attack-free period. Plasma fetuin-A is significantly and inversely highly correlated with the other inflammatory markers. Fetuin-A might be a novel indicator of disease activity in patients with FMF and could be used as an adjunctive marker for differentiation of FMF attacks. The negative correlation between serum fetuin-A and other inflammatory markers may also be indicative of inflammation-dependent downregulation of fetuin-A expression in FMF patients.