Cloning and mutation analysis of the human IL-18 promoter: a possible role of polymorphisms in expression regulation

Interleukin-18 is a proinflammatory cytokine, which strongly induces IFN-gamma production. We have cloned the human IL-18 promoter and screened for possible polymorphisms. Three single nucleotide polymorphisms were detected in the promoter and two polymorphisms in the 5'-nontranslated region of the gene. Three combinations of these polymorphisms were observed in the Swedish population. All IL-18 promoter alleles were found to have clear promoter activity when inserted into a luciferase reporter vector. There were no significant differences in promoter activity between alleles without stimulation, but after stimulation with PMA/ionomicin one of the alleles had clearly lower activity than the other (P