【Abstract】 Objective To investigate the association between the C627A polymorphism of the IL-10gene and asthma in an East-Chinese population.Methods A case-control study conducted in Qingdao,China.Reˉstriction fragment length polymorphism of amplified IL-10gene products was used to analyse the frequency of the C627A polymorphism in two groups including147asthma cases and184normal individuals.Total serum IgE levels were assayed.Results The C627A polymorphism of IL-10gene was found in Chinese population.The allele freˉquencies in asthma and controls were33%and21.7%,respectively,for the A allele(mutant)and67%and78.3%,respectively,for the C allele(wild type)(P<0.05,OR1.8,95%CI1.3,3.2).The IL-10genotype freˉquencies in asthma patients and controls were:17%(A/A),32.7%(A/C),50.3%(C/C)and7.1%(A/A),29.3%(A/C),63.6%(C/C),respectively(P<0.01,OR3.5,95%CI1.4,11.5).Serum concentration of IgE was significantly higher in carriers of an IL-10mutant allele compared with subjects with no mutant allele(P<0.01).Conclusion Carriage of the mutant allele of the IL-10C627A polymorphism is associated with elevated serum levels of IgE and development of asthma.