A case–control study of tumor necrosis factor-alpha promoter polymorphism and its serum levels in patients with chronic obstructive pulmonary disease in Kashmir, North India

AIM: Data about polymorphism in tumor necrosis factor-alpha (TNF-α) and its serum levels in chronic obstructive pulmonary disease (COPD) are conflicting. We aimed to evaluate the association of TNF-α-308 G > A polymorphism in patients with COPD in Kashmir (North India), a high burden area and also determined the serum TNF-α levels in these patients. MATERIALS AND METHODS: One hundred spirometrically confirmed COPD patients and 163 controls resident from Kashmir valley (North India) were recruited. Genotyping of the promoter region of TNF-α was carried out using polymerase chain reaction-restriction fragment length polymorphism. The serum TNF-α was quantified using the Cytometric Bead Array flex system by flow cytometry. Results were subjected to appropriate statistical treatment and P < 0.05 was considered statistically significant. RESULTS: Ninety-one COPD patients (91%) had G/G (wild homozygous) genotype and nine patients (9%) had G/A (heterozygous) genotype. Among the control population, 150 (92%) had G/G genotype and 13 (8%) had G/A genotype. The variant allele “A” was not detected in either of the two groups. Serum levels of TNF-α were significantly higher in patients compared to control group (8.0 ± 10.1 pg/ml vs. 3.3 ± 0.42 pg/ml, respectively, P = 0.0001). CONCLUSION: While serum levels of TNF-α are higher in COPD patients compared to the controls, there was no difference in the prevalence of TNF-α-308 polymorphism in the ethnic Kashmiri population with COPD.