Assessment of Interleukin-33 Levels in Patients with Familial Mediterranean Fever.

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.