Evaluation of small airways of Japanese childhood asthma by HRCT and its association with SNPs

Objectives:  The purposes of these studies were to evaluate small airways in childhood asthma by high-resolution computed tomography (HRCT) and to examine the association of single nucleotide polymorphisms (SNPs) with small airways' obstruction.

Methods:  Ten asthmatic patients (6 males & 4 Females) treated with ICS were recruited to the evaluation of small airways.  By using HRCT, low attenuation area (LAA) % and mean lung density (MLD) % were examined.  Ninety three patients (70 males & 23 females) were recruited to SNPs study and were divided into %FEF50%≥80% group (n=34) and %FEF50% <70% group (n=30).  We analyzed the SNPs of TGF-β1, MIF, IL-4Rα, IL-13 and IL-12β by using invader assy.

Results:  Under the condition of inspiration, MLD% and %FEF50% were significant correlated each other (r2=0.734, p<0.005) and LAA% and %FEF50% were significant inversely-correlated (r2=0.7881, p<0.005).  The patients of %FEF50%≥80% were recognized significantly more for GG allele of IL-13 (Arg110Gln) than the patients of %FEF50%<70% by chi-square test (p<0.05).

Conclusions:  Our results indicated that HRCT were also useful for the evaluation of small airways in childhood asthma same as in adulthood asthma, and that Japanese childhood asthmatic patients with small airways' obstruction showed significant SNPs of IL-13 (Arg110Gln).