Variations in the C3, C3a receptor, and C5 genes affect susceptibility to bronchial asthma

Koichi Hasegawa, Mayumi Tamari, Chenchen Shao, Makiko Shimizu, Naomi Takahashi, Xiao Quan Mao, Akiko Yamasaki, Fumiaki Kamada, Satoru Doi, Hiroshi Fujiwara, Akihiko Miyatake, Kimie Fujita, Gen Tamura, Yoichi Matsubara, Taro Shirakawa, Yoichi Suzuki

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79 Citations (Scopus)


Bronchial asthma (BA) is a common chronic inflammatory disease characterized by hyperresponsive airways, excess mucus production, eosinophil activation, and the production of IgE. The complement system plays an immunoregulatory role at the interface of innate and acquired immunities. Recent studies have provided evidence that C3, C3a receptor, and C5 are linked to airway hyperresponsiveness. To determine whether genetic variations in the genes of the complement system affect susceptibility to BA, we screened single nucleotide polymorphisms (SNPs) in C3, C5, the C3a receptor gene (C3AR1), and the C5a receptor gene (C5R1) and performed association studies in the Japanese population. The results of this SNP case-control study suggested an association between 4896C/T in the C3 gene and atopic childhood BA (P=0.0078) as well as adult BA (P=0.010). When patient data were stratified according to elevated total IgE levels, 4896C/T was more closely associated with adult BA (P=0.0016). A patient-only association study suggested that severity of childhood BA was associated with 1526G/A of the C3AR1 gene (P=0.0057). We identified a high-risk haplotype of the C3 gene for childhood (P=0.0021) and adult BA (P=0.0058) and a low-risk haplotype for adult BA (P=0.00011). We also identified a haplotype of the C5 gene that was protective against childhood BA (P=1.4×10-6 ) and adult BA (P=0.00063). These results suggest that the C3 and C5 pathways of the complement system play important roles in the pathogenesis of BA and that polymorphisms of these genes affect susceptibility to BA.

Original languageEnglish
Pages (from-to)295-301
Number of pages7
JournalHuman Genetics
Issue number4
Publication statusPublished - 2004 Sept
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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