Influence of proinflammatory cytokine gene polymorphisms on the risk of COPD and the levels of plasma protein.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a complex and multifactorial disease involving systemic inflammation. Although certain genetic components have been implicated in the development and progression of this disease, few studies have examined the participation of polymorphisms in proinflammatory genes and the extent to which polymorphisms are related to plasma levels of cytokines involved in the inflammatory process. METHODS: Of the 1125 smokers participating in the study, 438 had COPD, and 687 did not. We determined the genotype of 5 SNPs distributed in the genes: IL6, CXL8, CSF2, CCL1 and IL1B. The plasma protein expression of these genes was also evaluated and categorized according to genotype and the severity of COPD (GOLD grade). RESULTS: An analysis using the codominant model showed an association between rs1818879 in IL6 and susceptibility to COPD (GA OR = 1.1, AA OR = 1.77; p < 0.01), as well as an association between rs25882 in CSF2 and a greater severity of the disease (TC OR = 1.84, CC OR = 3.62; p < 0.01). No association was found between the presence of certain alleles in the SNPs and the plasma levels of the corresponding proteins. CONCLUSIONS: There are genetic polymorphisms related to susceptibility to COPD (rs1818879/A in IL6), as well as to the risk of greater severity of the disease (rs25882/T in CSF2). The presence of the alleles of interest did not significantly affect plasma levels of the codified proteins.

Single nucleotide polymorphisms in TNF are associated with susceptibility to aspirin-exacerbated respiratory disease but not to cytokine levels: a study in Mexican mestizo population.

AIM: To evaluate the association of three single nucleotide polymorphisms in TNF and one in LTA in Mexican patients with aspirin-exacerbated respiratory disease (AERD) and the correlation of those single nucleotide polymorphisms with serum levels of TNF-α. PATIENTS & METHODS: Case-control study including 133 patients with AERD, 135 patients with asthma (aspirin-tolerant asthmatics) and 182 healthy subjects. RESULTS: GA genotype of rs1800629 in TNF was found to be associated with the risk of developing AERD (p < 0.05; odds ratio = 2.36) and by dominant model (p < 0.05; odds ratio = 2.51). Furthermore, there was a difference in the serum levels between the aspirin-tolerant asthmatics group and the other groups (p < 0.001). CONCLUSION: The GA genotype of rs1800629 is associated with genetic susceptibility to AERD, but it does not correlate to protein serum levels.

Prevalence of alpha-1 antitrypsin high-risk variants in Mexican mestizo population and their association with lung function values.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is characterized by restricted airflow. The best-documented genetic factor is alpha-1 antitrypsin (AAT). AAT is encoded by the SERPINA1 gene. The PiZ (rs28929474) and PiS (rs17580) variants are believed to cause severe AAT deficiency and are linked to a high risk of developing COPD. This study sought to identify whether genetic polymorphisms rs28929474 and rs17580 are associated with COPD susceptibility and lung function values in a Mexican mestizo population. METHODS: In this study, 558 smokers were included, of whom 279 had COPD and 279 did not (smokers without COPD - SWC). The PiS and PiZ variants were genotyped by allelic discrimination. Independent populations and lung function values were compared using the Kruskal-Wallis test. A bivariate logistic regression analysis was also conducted. RESULTS: Stage I and iv COPD patients showed significant differences in the frequencies of both heterozygous genotypes compared to SWC. For PiS, individuals with the heterozygous genotype AT demonstrated a decreased FEV1/FVC ratio compared to subjects with the homozygous genotype AA (P=0.037). A significant association was found between the FEV1/FVC ratio and genotype AA for PiS (OR=0.982, ß coefficient=-0.019, 95% CI=0.966-0.997). CONCLUSIONS: COPD-causing AAT deficiency risk alleles exist at a very low frequency among Mexican mestizo population. Although they are not directly linked in our study population with disease susceptibility, these risk alleles are associated with poorer lung function measurements. It is important to characterize how often these genetic risk variants occur in other Latin American populations.