Gene polymorphisms of IL-6−174 G/C and IL-1Ra VNTR in asthmatic children

Abstract

To check for the association of genetic polymorphisms of IL-6-(-174)G/C and IL-1RaVNTR with the susceptibility and severity of asthma in Egyptian children. Subjects included 69 asthmatic children and 98 healthy unrelated controls from the Nile Delta of Egypt. Cases consisted of 20 males and 49 females with an age mean +/- SD is 7.5 +/- 2.1 ranging between 2-13 years. DNA amplification using PCR with sequence-specific primers was done for detection of promotor single nucleotide polymorphism of IL-6 gene as well as intron 2 VNTR of IL-1Ra gene. Frequency of case-genotypes or alleles were compared to controls using Fisher exact test and Odds ratio. Cases showed significant higher frequency of the genotypes: IL-6-174 GG (P<0.05, OR=3.2, 95% CI=1.09-10) that was evident mainly in the uncontrolled asthma subgroup indicative of the possibility of being a severity genotype. All cases as well as case-subgroups showed high significant frequency of IL-1Ra A1A1 (p<0.0001, OR=1.5, 95% CI=1.3-1.8). This may be considered a susceptibility genotype. Cases have also shown significant lower frequency of IL-6(-174) GC and IL-1Ra A1A2 genotypes (P<0.001 and P<0.0001 respectively). IL-6 and IL-1Ra polymorphisms can be considered genetic markers for bronchial asthma susceptibility and/or severity among Egyptian children. This may have a potential impact on family counseling and management.