Can serum fetuin-A be regarded as an inflammatory marker among patients with familial Mediterranean fever?

Background/aim: 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.

Methods: 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).

Results: 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.

Conclusion: 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.