Association of the SNP rs1800925(C/T) in the Interleukin-13 Gene Promoter with Pulmonary Function in Chinese Han Patients with Idiopathic Pulmonary Fibrosis

The present report studied potential association of the rs1800925(C/T) single nucleotide polymorphism (SNP) of the Interleukin (IL)-13 gene promoter with idiopathic pulmonary fibrosis (IPF) in patients of Chinese Han ethnicity. Seventy patients with IPF were enrolled and divided into three subgroups: group A (61-79 % pred. DLCO; n = 22), group B (51-60 % pred. DLCO; n = 20), and group C (a parts per thousand currency sign50 % pred. DLCO; n = 28). Control group consisted of 80 healthy individuals of Chinese Han ethnicity. The SNP rs1800925(C/T) was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The IL-13 CC genotype was present in 28/70 (40.0 %), homozygous TT in 6/70 (8.6 %) and heterozygous CT in 36/70 (51.4 %) patients with IPF. In control group, these genotypes were present in 30/80 (37.5 %), 11/80 (13.75 %), 39/80 (48.75 %), respectively, indicating that the distribution of the above three genotypes was not significantly different between patients with IPF and healthy controls. When the patients were stratified according to their DLCO and DLCO/VA, the frequencies of genotypes CT and TT in the groups A, B, and C were, respectively, 40.9 % (9/22), 50 % (10/20), and 82.1 % (23/28). Thus, significant differences in the distribution of alleles at -1112 region of IL-13 gene were observed among the study groups A, B, and C, with the highest frequency in group C (p < 0.05). In conclusion, the rs1800925 T allele of the IL-13 gene is associated with worse pulmonary function in patients with IPF of Chinese Han ethnicity.