RESUMO
Pro- and anti-fibrotic cytokine gene polymorphisms may affect expression of idiopathic pulmonary fibrosis (IPF). The aims of the present case-control study were to examine polymorphisms in the IL-6, transforming growth factor (TGF)-beta 1, tumour necrosis factor (TNF)-alpha and interleukin-1 (IL-1)Ra genes in patients with IPF (n = 22) -compared to healthy controls (n = 140). Genotyping was performed on DNA extracted from peripheral blood lymphocytes, using polymerase chain reaction - restriction fragment length polymorphism with gene polymorphisms determined according to -published techniques. The following sites were examined: (i) IL-1Ra*1-5 (86 bp variable tandem repeat intron 2), (ii) IL-6 (-174G > C), (iii) TNF-alpha (-308G > A) and (iv) TGF-beta 1 (Arg25Pro). The TNF-alpha (-308 A) allele was over-represented in the IPF (p(corr) = 0.004) group compared to controls. Risk of IPF was significant for heterozygotes for: (i) the TNF-alpha (-308 A) allele (A/G) (odds ratio (OR) 2.9; 95% confidence interval (CI) 1.2-7.2; P = 0.02), (ii) homozygotes (A/A) (OR 13.9; 95%CI 1.2-160; P = 0.04) and (iii) carriage of the allele (A/A + A/G) (OR 4; 95%CI 1.6-10.2; P = 0.003). The distribution of alleles and genotypes for IL-6, TGF-beta 1 and IL-1Ra between the two groups was not significantly different. This is the third study to independently confirm that there is a significant association of the TNF-alpha (-308 A) allele with IPF. Further research is needed to assess the utility of cytokine gene polymorphisms as markers of disease -susceptibility.
Assuntos
Citocinas/genética , Polimorfismo Genético/genética , Fibrose Pulmonar/genética , Idoso , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Proteína Antagonista do Receptor de Interleucina 1 , Interleucina-1/genética , Interleucina-6/genética , Masculino , Pessoa de Meia-Idade , Queensland , Sialoglicoproteínas/genética , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta1 , Fator de Necrose Tumoral alfa/genética , População Branca/genéticaRESUMO
Infection frequently causes exacerbations of chronic obstructive pulmonary disease (COPD). Mannose-binding lectin (MBL) is a pattern-recognition receptor that assists in clearing microorganisms. Polymorphisms in the MBL2 gene reduce serum MBL levels and are associated with risk of infection. We studied whether the MBL2 codon 54 B allele affected serum MBL levels, admissions for infective exacerbation in COPD and disease susceptibility. Polymorphism frequency was determined by PCR-RFLP in 200 COPD patients and 104 smokers with normal lung function. Serum MBL was measured as mannan-binding activity in a subgroup of 82 stable COPD patients. Frequency of COPD admissions for infective exacerbation was ascertained for a 2-year period. The MBL2 codon 54 B allele reduced serum MBL in COPD patients. In keeping, patients carrying the low MBL-producing B allele had increased risk of admission for infective exacerbation (OR 4.9, P(corrected)=0.011). No association of MBL2 genotype with susceptibility to COPD was detected. In COPD, serum MBL is regulated by polymorphism at codon 54 in its encoding gene. Low MBL-producing genotypes were associated with more frequent admissions to hospital with respiratory infection, suggesting that the MBL2 gene is disease-modifying in COPD. MBL2 genotype should be explored prospectively as a prognostic marker for infection risk in COPD.