Role of interleukin-18 in allergic rhinitis

The role of IL-18 has not been well studied in allergic rhinitis. Few studies demonstrated up- regulation of IL-18 in nasal discharge of allergic rhinitis patients. The persistence of elevated IL-18 concentrations until after the season suggests a role for this cytokine in persistent allergic inflammation. In this study, we tried to through light on this role in patients with allergic rhinitis by investigating whether polymorphism is present in the coding regions of the IL-18 gene and, if so, to further analyze the association between polymorphism and allergic rhinitis in a case-control study. Blood samples were collected from 32 patients and 8 healthy controls matched by age and sex. Every patient was subjected to skin prick test [SPT] to confirm the clinical diagnosis and to detect the causative allergen[s]. Sera from the patients and controls were analyzed by using PCR single-nucleotide polymorphisms [SNPs]. There was a significant difference of IL-18 gene polymorphism at position -137 among allergic rhinitis patients and controls. The frequency of the -137C allele was significantly higher among allergic rhinitis patients as compared to the controls. We concluded that IL-18 gene polymorphism may represent an important susceptibility biomarker for the increased susceptibility to allergic rhinitis. This study reinforced the need for in-depth analysis of immune dysregulation of patients with allergic rhinitis arid point to the potential usefulness of cytokine-based therapy