Aim: Positive acute-phase reactants generally increase during the attack period (AP) of familial Mediterranean fever (FMF) and return to normal range in the attack-free period (AFP). In some patients, the level of these acute-phase reactants does not decrease during the AFP, suggesting that subclinical vascular inflammation continues during the AFP. In the context of this information, we tested whether apelin and fetuin-A can be used as inflammatory biomarkers in the AFP of FMF patients.
Material and Method: Thirty FMF patients within AFP and thirty healthy subjects were included in this study. Serum apelin and fetuin-a levels were measured using enzyme-linked immunosorbent assay (ELISA) method.
Results: The median levels of apelin were 113.07±15.9 ng/L in FMF and 307.82±52.76 ng/L in healthy subjects (p= 0.002). The median levels of fetuin-A were 1352.2±127.61 ng/mL in the FMF group and 843.82±137.66 ng/mL in the control group (p= 0.009). In FMF patients, there was a significant correlation between apelin and fetuin-A levels (r = 0.399; p = 0.029). Furthermore, a significant inverse correlation was found between age and apelin (r= -0.499; p = 0.005), and a significant positive correlation was found between BMI and apelin (r = 0.769; p = 0.001). Additionally, a significant correlation was found between BMI and fetuin-A (r = 0.397; p = 0.030).
Discussion: Lower serum apelin levels and higher fetuin-A levels were observed in FMF patients with AFP than in healthy subjects, suggesting that subclinical vascular inflammation continues during AFP in patients with FMF. Further studies with large study populations and different ethnic groups are necessary to show the role of apelin and fetuin-A in subclinical inflammation resulting from FMF.