Investigation of the Levels of Serum Amyloid A, YKL-40, and Pentraxin-3 in Patients with Familial Mediterranean Fever.

Background: Familial Mediterranean Fever (FMF) is an autosomal recessive form of recurrent episodes of fever and an autoinflammatory disease characterized by inflammation of the serous membranes. The clinical diagnosis is supported by the laboratory findings. This study investigated the relationship of Serum Amyloid A (SAA), YKL-40, and Pentraxin-3 (PTX-3) with the FMF disease.

Methods: About 50 patients with FMF were enrolled in this study. Patients were divided into three groups according to disease severity score (mild, moderate, and severe). Thirty-seven healthy individuals were included as the control group. Serum SAA, YKL-40, and PTX-3 concentrations were measured using an ELISA kit.

Results: Serum SAA and YKL-40 levels of FMF patients were significantly higher than in the control (P < 0.001). PTX-3 levels were found to be higher in patients even though there was no significant difference (P = 0.113). Whereas the positive predictive value was 71.9% for cut-off point of SAA, the positive predictive value was 83.3% for cut-off point of YKL-40. Whereas a significant correlation was detected in SAA and PTX-3 with YKL-40 (respectively; P = 0.036, P < 0.001), there was no correlation between the PTX-3 with SAA (P = 0.219).

Conclusions: YKL-40 can be used together with SAA to support the diagnosis of FMF and to monitor the severity of the disease. In this study, YKL-40 levels were examined for the first time in FMF patients and further studies are necessary using larger patient samples.