Interleukin-18 promoter polymorphism in patients with atopic asthma

Area of Science:

• Immunogenetics
• Respiratory Medicine

Background:

• Allergic asthma is a chronic inflammatory condition where Interleukin-18 (IL-18) is implicated.
• Previous research on IL-18 promoter polymorphisms as markers for asthma susceptibility remains inconclusive.

Purpose of the Study:

• To investigate the association between IL-18 promoter gene polymorphisms (-137 and -607) and allergic asthma in a Polish population.
• To determine if specific IL-18 promoter genotypes, alleles, diplotypes, or haplotypes correlate with asthma severity.

Main Methods:

• Analysis of 231 allergic asthma patients diagnosed via NHLBI/WHO guidelines.
• Utilized allele-specific polymerase chain reaction to examine IL-18 gene promoter polymorphisms at positions -137 and -607.
• Compared genotype, allele, diplotype, and haplotype frequencies between asthma patients and controls, and across asthma severity groups.

Main Results:

• No significant differences in IL-18 promoter polymorphism frequencies were found between the overall asthma group and controls.
• Patients with severe asthma showed a higher prevalence of -607 CC and -137 GG genotypes compared to controls.
• The -137 CC genotype was more common in mild to moderate asthma patients.
• Significant differences in -137 allele frequencies were observed between mild-to-moderate and severe asthma groups (P = 0.006).

Conclusions:

• IL-18 promoter polymorphisms at -607 and -137 do not appear to be independent markers for general allergic asthma susceptibility.
• The -137 G allele and the C-G/C-G diplotype are potentially associated with the pathogenesis of severe allergic asthma.
• Further research is warranted to elucidate the specific role of IL-18 in severe asthma development.