Macrophage migration inhibitory factor gene polymorphisms (SNP ‐173 G>C and STR‐794 CATT5‐8) confer risk of plaque psoriasis: A case–control study

BACKGROUND: Macrophage inhibitory factor (MIF) is a pro‐inflammatory cytokine secreted by several cells, including those in the immune system and the skin. The MIF gene contains the SNP ‐173 G> C and STR ‐794 CATT(5‐8) polymorphisms in the promoter region capable of affecting its activity. Our objective was to investigate the MIF polymorphisms as a risk factor for plaque psoriasis (PP) in the Mexican population. METHODS: We genotyped both MIF polymorphism (rs5844572 and rs755622) in 224 PP patients with a clinical and histopathological diagnosis and 232 control subjects (CS) by the PCR‐RFLP method. MIF serum levels were determined by an ELISA kit. RESULTS: We found significant differences in the genotypic and allelic frequencies for the MIF ‐173 G>C polymorphism; carriers of the GC genotype (OR 1.51, 95% CI 1.026–2.228, p = 0.03) and the C allele (OR 1.34, 95% CI 1.005–1.807, p = 0.04) had higher odds to present with PP. Moreover, the 6C haplotype was associated with PP risk (OR 2.10, 95% CI 1.22–3.69, p < 0.01). Also, the ‐173 CC genotype was associated with high MIF serum levels (p < 0.05). CONCLUSIONS: The ‐173 GC genotype and the 6C haplotype of the MIF polymorphisms are associated with susceptibility to PP in the Mexican population.