Abstract
Background Familial Mediterranean fever (FMF) is a systemic autoinflammatory disease genetically transmitted with the autosomal recessive trait. Although the pathogenesis is not certain, it is known that there is a deficiency in the regulation of the natural immune system. In this study, we aimed to search whether patients with FMF are predisposed to respiratory tract infections and whether mannose-binding lectin (MBL), as a natural immune system member, contributes to it. Methods Fifty FMF patients and 20 control groups were enrolled in the study. First, the frequencies of upper respiratory tract infection (URTI) within the previous year of both patient and control groups were evaluated retrospectively. Then, both groups were followed up for URTI for one year after starting the study. The patient's immunoglobulin A (IgA), IgM, IgG, C-reactive protein (CRP), hemogram parameters, and mannose-binding lectin were evaluated. Results The median frequency of annual URTI with a retrospective evaluation of patients was higher than that of the control group. Also, the median frequency of URTI with the prospective evaluation of patients with FMF was higher than the control group. The rate of patients with low serum IgG levels was higher in the patient group than in the control group. However, serum IgG levels of FMF patients with frequent URTI were not different from those without. The median MBL levels of both groups were similar (1312 vs. 1534 ng/ml for the patient and control group, respectively). The rate of patients having low serum MBL levels was also similar between the groups. Conclusions In the present study, we found that patients with FMF had more URTI than healthy controls. However, the underlying cause is not fully explained. There is a need for further studies with a higher number of patients evaluating URTI in patients with FMF.