High risk association of IL-4 VNTR polymorphism with asthma in a North Indian population.

Background: A case-control study was conducted to evaluate the role of IL-4 VNTR polymorphism in asthma that has been associated with various inflammatory diseases worldwide. This is the first case-control study conducted in India, investigating the role of IL-4 VNTR polymorphism in asthma pathogenesis.

Methods: A case-control study was performed with a total of 824 adult subjects, inducting 410 asthma patients and 414 healthy controls from North India. The genotypes were identified by polymerase chain reaction.

Results: Statistical analysis for the IL-4 VNTR polymorphism revealed that the Rp1 allele was significantly associated with asthma with OR=1.47, 95% CI (1.11-1.94) and p=0.005. The Rp1/Rp1 homozygous mutant genotype posed a high risk towards asthma with OR=2.39, 95% CI (0.96-6.14) and p=0.040. The Rp2/Rp1 heterozygous genotype also posed a risk towards asthma with OR=1.39, 95% CI (1.00-1.94) and p=0.040. Most of the phenotypic traits were significantly associated with the disease.

Conclusions: IL-4 VNTR polymorphism is a high risk factor for asthma in the studied North Indian population.