[A study on the relationship between interleukin-4 promoter polymorphism and asthma in a Xinjiang Uyger population].

Objective To investigate the potential association of interleukin-4(IL-4) polymorphism -589(C/T) with specific clinical phenotypes of asthma in Xinjiang Uygur population. Methods Ninety-three Uyger asthmatics [asthmatic group(A), mild 30(A 1), moderate 32(A 2), severe 31(A 3); nocturnal asthma 41(A [KG-*3]Ⅰ), nonnocturnal asthma 52(A Ⅱ)] in whom linkage of asthma and atopy to chromosome 5q 31-33 was suggested and 62 normal healthy controls (B group) with the same ethnicity nearby Xinjiang Hetian region were investigated. The IL-4 -589(C/T) polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) analysis. The serum eosinophil cationic protein(ECP) and total IgE and specific aeroallergens were detected using a Pharmacia UniCAP 100 type instrument, and pulmonary ventilatory function was measured by FEV 1% and PEF. in whom linkage of asthma and atopy to chromosome 5q 31-33 was suggested and 62 normal healthy controls (B group) with the same ethnicity nearby Xinjiang Hetian region were investigated. The IL-4 -589(C/T) polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) analysis. The serum eosinophil cationic protein(ECP) and total IgE and specific aeroallergens were detected using a Pharmacia UniCAP 100 type instrument, and pulmonary ventilatory function was measured by FEV 1% and PEF. Results The IL-4 polymorphism-589(C/T) frequency of the heterozygous CT was 42(45.1%), homozygous CC 29(31.2%),and homozygous TT 22(23.7%)in A group. The frequency of the heterozygous CT was 26(41.9%), homozygous CC 21(33.9%),and homozygous TT 15(24.2%)in B group. There were no significant differences in the distributions of the three genotypes between A group and B group (P0.05). The frequency of the homozygous CC was 39.0% in the A Ⅰ group as compared to 25.0% in the A Ⅱ group, the difference being significant(P=0.026). The frequency of the heterozygous CT was 40%(12/30) in A 1 group, 41%(13/32) in A 2 group and 55%(17/31) in A 3 group. There were significant differences in the distributions of the three genotypes among A 1, A 2 and A 3 group(all P0.05). The total serum IgE levels were (75.2±43.2)kU/L and (52.3±22.4)kU/L in A group and B group respectively, and there was no significant difference in the levels of total serum IgE among the genotypes in both A and B groups(P0.05). The serum ECP levels were (7.9±5.4)μg/L and (4.8±1.9)μg/L in A group and B group respectively, the difference being significant between the two groups(P0.01). The positive rate of specific IgE antibody was 18.3%(17/93), and 0%(0/62) in A group and B group respectively, and there was significant difference between the two groups(P0.01). Conclusions It is suggested that the IL-4 promoter -589(C/T) polymorphism may be associated with nocturnal phenotypes of asthma, but not associated with pulmonary ventilatory function(P0.05) and serum total IgE level in this Xinjiang Uyger population.