Multilocus haplotype analyses reveal association between 5 novel IL-15 polymorphisms and asthma

Area of Science:

• Immunology
• Genetics
• Allergy Research

Background:

• Interleukin-15 (IL-15) is a cytokine implicated in T-cell mediated inflammatory and autoimmune diseases.
• Upregulation of IL-15 is observed in various T-cell mediated inflammatory disorders.
• IL-15 may play a role in both T(H)1 and T(H)2 mediated inflammatory conditions.

Purpose of the Study:

• To identify single nucleotide polymorphisms (SNPs) within the IL-15 gene.
• To investigate the association of these IL-15 gene polymorphisms with inflammatory and atopic phenotypes, specifically asthma and atopy.

Main Methods:

• Screening for SNPs using single-strand conformation polymorphism (SSCP) analysis.
• Genotyping of identified polymorphisms via restriction fragment length polymorphism (RFLP).
• Association analysis using Armitage trend test and haplotype frequency estimation with FASTEHPLUS and FAMHAP programs.

Main Results:

• Five novel noncoding nucleotide sequence variants in the IL-15 gene were identified and genotyped.
• No significant association was found between individual IL-15 polymorphisms and the phenotypes of bronchial asthma or atopy.
• Multilocus haplotype analysis revealed a highly significant association between IL-15 haplotypes and asthma (P = 6.1 x 10(-5)) and a nominally significant association with atopy (P = 0.0232).

Conclusions:

• The findings reinforce the potential involvement of IL-15 in the pathogenesis of allergic diseases.
• Specific combinations of IL-15 gene variants (haplotypes) are strongly associated with asthma and atopy.
• Further research into the role of IL-15 in allergic inflammation is warranted.