Mannose binding lectin (MBL) gene polymorphism and relationship between serum MBL concentrations in COPD patients

Aim: We aimed to assess mannose-binding lectin (MBL) gene polymorphisms and serum MBL concentrations in a sample of Turkish chronic obstructive pulmonary disease (COPD) patients as well as in cigarette smokers. Furthermore, we looked for the possible correlations of serum MBL concentrations with pulmonary function tests. Materials and methods: Forty COPD patients and 40 healthy volunteers were included. The subjects were thereafter divided into 2 groups according to smoking status. Circulating MBL concentrations were assessed by ELISA and MBL gene polymorphisms were assessed by real time PCR method. Spirometry was performed to all subjects except healthy nonsmokers. Results: In the whole study population MBL gene frequencies were found 82.5%(66/80) for A/B genotype, 15%(12/80) for D/D genotype and 2.5%(2/80) for B/B genotype. Circulating MBL concentrations were found 2103 +/- 1311 ng/ml and 2324 +/- 1001 ng/ml in smoker and nonsmoker COPD patients, respectively, whereas they were 1746 +/- 1142 ng/ml in smoker and 2040 +/- 879 ng/ml in nonsmoker controls. No statistical difference was found between the study groups for serum MBL concentrations. Serum MBL concentration correlated positively with cigarette smoking (r=0.280, p=0.030) and negatively with pulmonary functions (FEV1 (r=-0.246, p=0.058). Conclusion: To our knowledge, no previous study has been performed in healthy Turkish population to detect the MBL gene polymorphisms. A/B genotype was the most frequent MBL variant in our study population; however serum MBL concentrations were not found compatible with MBL deficiency. We believe these results need further investigation which includes larger series to evaluate whether serum MBL concentration is a risk factor for COPD.