Background Familial Mediterranean fever (FMF) is characterized by recurrent febrile inflammatory attacks of serosal and synovial membranes. Although genetic disorder leading to disease is almost the same, clinical phenotype is quite variable suggesting role of other pathogenetic factors. Serum antimicrobial peptides (AMPs), cathelicidin and defensins, are naturally occurring peptides produced from epithelial tissues and neutrophils. Beside their direct antimicrobial activity, AMPs have immunomodulatory functions including chemotaxis, opsonisation, cytokine, chemokine and compleman activation that may produce or promote inflammation. Their pathogenetic role in numerous autoinflammatory diseases has been reported.
Objectives To investigate the serum antimicrobial peptides in patients with FMF and its clinical associations.
Methods twenty-three newly diagnosed FMF patients (14 female, mean age 35.6 years) were enrolled and prospectively followed for six months. Demographic data, disease characteristics and MEFV genotypes were obtained with standardized questionnaires. Age- and sex- matched 24 healthy subjects were constituted control group. Serum alpha defensin (HNP1), beta defensins (hBD1 and hBD2) and cathelicidin (LL37) levels were measured with ELISA, before and six months after treatment and if there was an attack in this time period.
Results pretreatment concentrations of HNP1, hBD1 and LL37 were significantly higher in FMF patients compared to healthy control subjects and remained throughout after colchicine treatment. HNP1 concentration was reduced to pretreatment levels with colchicine. In six-months follow up period 13 patients experienced at least one attack. During attacks any significant difference observed in any of the serum AMP concentrations. Interestingly, none of serum AMPs correlated with acute phase reactants. Likewise, none of AMPs correlated with frequency of attacks.
Conclusions Increased levels of serum AMPs in FMF patients suggest that neutrophils are active in the course of disease despite colchicine treatment. We did not find any correlation between FMF disease characteristics and serum AMPs suggesting they are not associated with clinical phenotype of FMF.
Disclosure of Interest None Declared