IL-10(-1082(G-->A)) G/G and TNF-alpha-308(G-->A) G/G may be a contributing factor in susceptibility as well as severity of asthma among Egyptian children.
The tumour necrosis factor-alpha gene nucleotide -308 polymorphism is associated with a moderately increased risk of asthma and bronchial hyperresponsiveness, but not with atopy.
Similarly, the A allele of the TNF-238 SNP was associated with increased asthma risk among children of nonsmoking parents (RR = 2.21; 95% CI, 1.14-4.30; p for interaction = 0.01).
The HLA (human leukocyte antigen) class II genes DQB1 and DRB1 and the Tumor Necrosis Factor alpha gene (TNFA) within the HLA complex (chromosome 6p21) have been associated with asthma and allergy.
Among asthmatic children carrying the TNFalpha -308A allele, there were significantly more patients positive for C. pneumoniae-specific IgG, than among control children carrying the same allele (20.1% versus 9.2% of asthmatic versus control children, respectively; p = 0.002; odds ratio = 3.52 (1.52-7.53); p = 0.005).
Our results suggest that TNFA or nearby genes, including those in the major histocompatibility complex region, may contribute to the development of asthma in the Japanese population.
This may suggest that TNF-alpha as well as IFN-alpha are secreted by fungi-prestimulated leukocytes from the lower respiratory tract and may be involved in the processes of exacerbation of asthma complicated by fungal infections.