Airway levels of LPS (P=0.003), CXCL8 (P=0.004), CCL5 (P=0.029), IL-6 (P=0.004), and IL-13 (P<0.001) were significantly higher in infants who later developed recurrent wheezing than those who did not.
We were unable to confirm associations of the positional candidates DPP10 and PHF11 with wheeze, although our study had ample power to detect the expected associations of IL13 variants with IgE and SPINK5 variants with eczema.
To determine whether infants exposed to environmental tobacco smoke (ETS) having the interleukin 4 (IL-4) or interleukin 13 (IL-13) gene polymorphisms were at increased risk of wheezing.
Maternal smoking during pregnancy was associated with early-onset persistent wheeze (OR 2.93, p < 0.0001); polymorphisms in IL13 were not (OR 1.15, p = 0.60 for the common haplotype pair).
Most importantly, the IL-13 Gln allele was associated with late wheezing (odds ratio 3.27, 95% confidence interval 1.32-8.06), but it was not associated with early wheezing.
We examined the relationship between these single nucleotide polymorphisms and PHA-induced cytokine (IL-5, IL-10, IL-13, and IFN-gamma) response profiles at birth and at year 1, respiratory syncytial virus-induced wheezing and atopic dermatitis in the first year of life, and total IgE levels, peripheral blood eosinophil counts, and allergic sensitization at age 1 year.