Association Of Polymorphisms Of Interleukin-16 And Interleukin-18 Gene Promoter Region With Asthma

Objective: 1. To investigate the distribution of interleukin-16 and interleukin-18 gene polymorphisms in Han nationality in Jiangxi Chinese population. 2. To investigate the association between the -295T/C promoter polymorphism in the IL-16 gene and asthma in Han nationality in Jiangxi Chinese population. 3. To investigate the association of IL-18 gene promoter 1 polymorphisms (-607C/A,-137G/C)with asthma in Han nationality in Jiangxi Chinese population.Method: Allele Specific-PCR and Sequence Analysis were used to establish the genotype and allele frequencies of the -295T/C promoter polymorphism in Han nationality in Jiangxi Chinese population, which included 76 asthmatic patients, 73 nonasthmatic controls;Using Polymerase Chain Reaction with Sequence Specific Primer(PCR-SSP) and Sequence Analysis, the single nucleotide polymorphisms (SNPs) of the promoter 1 region of IL-18 gene at position -607 and -137 were detected in 82 asthmatic patients (group A) [27 patients with asthma and allergic rhinitis(AR) (group A1), 55 patients with asthma without AR (group A2)] and 78 healthy controls (group B). then analyzed with Chi-square test.All statistics were analyzed by software SPSS 13.0.Result: (1)In asthmatic patients and nonasthmatic controls,the allele frequencies were 78.3%(T), 21.7%(C); 79.5%(T), 20.5%(C),respectively. No significant difference in the allele frequencies of IL-16 gene polymorphism was found between asthmatic patients and nonasthmatic controls(P>0.05).(2) The frequencies of allele C at position -607 in the promoter 1 of IL-18 gene were 50.6%(group A),38.9%(group A1),56.4%(group A2),46.2% (group B),respectively.The frequency of allele C in group A2 was significantly higher than that in group A1 (χ2=4.425 P=0.035<0.05). (3)The frequencies of allele C at position -137 in the promoter 1 of IL-18 gene were 17.7% (group A),29.5% (group A1),11.8% (group A2),15.4% (group B) ,respectively. The frequency of allele C in group A1 was significantly higher than that in group B (χ2=5.27 P=0.022<0.05) and that in group A2 ((χ2=7.789 P=0.005<0.01). (4)The frequencies of -607C/-137G haplotype were 45.1% (group A),33.3% (group A1),50.9% (group A2),41.8% (group B) ,respectively. The frequency of -607C/-137G haplotype in group A2 was significantly higher than that in group A1 (χ2=10.862 P=0.012<0.05). (5)The frequencies of -607A/-137C haplotype were 12.2% (group A),22.2% (group A1),7.3% (group A2),11.5%(group B) ,respectively.The frequency of -607A/-137C haplotype in group A1 was significantly higher than that in group A2(χ2=7.559 P=0.006<0.01).Conclusion :(1)The IL-16 -295T/C promoter polymorphism is not associated with asthma in Han nationality in Jiangxi Chinese population. (2)Allele C at position -137 in the promoter 1 region of IL-18 gene is associated with the patients with asthma and AR in Han nationality in Jiangxi Chinese population.(3) The distribution of the the single nucleotide polymorphisms of the promoter 1 region of IL-18 gene at position -607 and -137 are different between the patients with asthma and AR and the patients with asthma without AR. These findings may imply that IL-18 plays a different role in the pathophysiology of asthma and allergic rhinitis.