Serum macrophage migration inhibitory factor (MIF) in the intercritical phase of hereditary periodic fevers and its relationship with the -173 MIF gene polymorphism

OBJECTIVES: To examine the association of the -173 single-nucleotide G/C polymorphism of the macrophage migration inhibitory factor gene (MIF) and serum macrophage migration inhibitory factor (MIF) concentrations in a group of Italian patients with hereditary periodic fevers (HPF), tested during a symptom-free phase of their disease. METHODS: Genomic DNA for MIF and serum MIF were evaluated in 22 patients with HPF and compared with healthy controls of the same ethnic group. The MIF-173G/C polymorphism was genotyped using polymerase chain reaction (PCR) and visualized by ethidium bromide staining. Serum MIF levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: MIF-173*C allele frequency and MIF serum concentrations were significantly higher in patients with HPF than in controls, with no statistically significant difference between familial Mediterranean fever (FMF) and hyperimmunoglobulinaemia D/periodic fever syndrome (HIDS) and no correlation with specific MIF genotypes. CONCLUSIONS: The MIF-173*C allele was found more frequently in patients with HPF than in controls and MIF serum concentrations were considerably elevated in attack-free phases, suggesting a persistent state of subclinical cytokine activation with MIF involvement in the autoinflammatory cascade.