Case-control study of relationship between polymorphisms of interleukin-4 gene and susceptibility of silicosis

Abstract

To explore the relationship between polymorphisms of interleukin-4 (IL-4) gene (-33, +45, VNTR, +429, +448) and the susceptibility of silicosis. In a case-control study, the case group consisted of 101 patients with silicosis, and was matched with the control group (121 workers without silicosis), according to the age, sex, nationality, working place, exposure to dust. The polymorphisms of IL-4 (five locus) detected by the method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. There was no difference of age, exposure and smoking between case group and control group (P > 0.05). The two groups had good comparability. Only the GA genotype in the IL-4 (+429) locus was found, the genotypes of AA and GG were not found. The CC genotype in the IL-4 (+448) locus was found, the genotypes of CG and GG were not found. The frequencies of AA, GG and AG of IL-4 (+45) locus in the case and control groups were 55.4%, 10.9%, 33.7% and 62.0%, 11.6%, 26.4%, respectively, there was no the significant difference between case and control groups (P > 0.05). The frequencies of B1B1, B2B2 and B1B2 of IL-4 (VNTR) locus in the case and control groups were 73.3%, 1.0%, 25.7% and 68.6%, 1.7%, 29.8%, respectively, there was no the significant difference between case and control groups (P > 0.05). The frequencies of TT, CC and CT in IL-4 -33 locus in the case group were 55.4%, 11.9% and 32.7%, which were significantly higher than those (69.4%, 4.1%, 26.4%) in control group (P < 0.05). There was no relationship between IL-4 (+45, VNTR) genotypes and prevalence of silicosis in this study. The polymorphisms of IL-4 (+448) site were not found which may be related to the race. The relationship between genetic polymorphism of IL-4 (-33) locus and silicosis development was found, Workers with IL-4 (-33) allele C are susceptible to the silica.