Association of mannose binding lectin with chronic obstructive pulmonary disease susceptibility and its clinical outcomes

Background The physiological interactions of MBL suggest its contribution towards the pathogenesis of COPD. Objective The present case–control study was undertaken to elucidate the role of MBL with COPD risk and clinical outcomes in north Indian cohort. Methods Patients were enrolled as per GOLD criteria. MBL2 variants were selected based on the literature and their putative functional significance. Genotyping of six single nucleotide polymorphisms of MBL2 comprising of two coding (rs1800450, rs1800451) and four non-coding variants (rs11003125, rs7096206, rs11003123 and rs7095891) was done by using PCR–RFLP and ARMS-PCR. Serum MBL levels were analysed by sandwich ELISA. Results Overall findings of the molecular genetic analysis of MBL2 indicated significant difference in frequency of three of the six studied variants, between patients and controls or among different disease severity stages. Heterozygous genotype of rs7095891 showed significant protective association towards severity of disease. Linkage disequilibrium (LD) analysis indicated a strong LD between rs1800450 and rs7095891 while intermediate LD was observed for rs11003123/rs11003125 and rs7096206/rs11003125. Haplotype analysis revealed 17.14-fold risk of developing exacerbations conferred by GGGTGG haplotype. Significantly low serum MBL levels observed in COPD patients as compared to controls. Significant difference in MBL deficiency levels were also observed for homozygous wild and variant genotypes of rs11003125 and rs7096206 respectively, as well as for all genotypes of rs11003123 than respective controls. Conclusion The present study reinforces the role played by MBL in the susceptibility, protection and clinical outcomes of COPD. Therefore, including the reported associations at diagnostic, prognostic and therapeutic interventions may prove helpful.