Abstract Background This study was designed to evaluate the relationship between serum interleukin-33 (IL-33) levels and clinical features of the disease in patients with Familial Mediterranean Fever (FMF). Methods Fifty-four patients diagnosed with FMF (28 colchicine responsive and 26 colchicine resistant) and 29 healthy controls constituted the study population. Demographic, clinical, biochemical and inflammatory parameters, as well as serum IL-33 levels of the participants, were compared. Results The mean age of FMF patients was 34.3 ± 9.8 years, and 54% were female. Colchicine-resistant patients exhibited significantly higher median CRP levels than both colchicine-responsive patients and healthy controls (median IQR: 16 30.4 mg/L, 2.9 3.4 mg/L, and 3.4 2.8 mg/L, respectively; p < 0.001). Median serum IL-33 levels were higher in FMF patients than in controls (273 387 ng/L vs. 221 179 ng/L, p = 0.06). The colchicine-responsive group had significantly higher IL-33 levels compared to the control group (287 495 ng/L vs. 221 179 ng/L, p = 0.006), while no significant difference was observed between the colchicine-resistant group and controls (257 219 ng/L vs. 221 179 ng/L, p = 0.74). No significant correlations were identified between IL-33 levels and inflammatory markers or clinical characteristics. Conclusions Serum IL-33 levels do not seem to be associated with FMF disease activity; however, the observed increase in colchicine-responsive patients may indicate an immunomodulatory or compensatory function. Further comprehensive studies are needed to elucidate the role of IL-33 in FMF pathogenesis.
Demirezen et al. (2026) studied this question.