Background Bronchial asthma is a chronic inflammatory disorder of the airways. Recently, it has been suggested that complement plays significant roles in asthma. Mannose-binding lectin (MBL) is one of the key molecules in complement activation pathways that are associated with several infectious and immune disorders.
Subjects and method To investigate whether MBL plays roles in asthma, we analysed MBL2 polymorphisms (allele B, H/L and Y/X) and plasma MBL levels in a Japanese adult population including 232 healthy controls and 579 asthmatics.
Results Although there was linkage disequilibrium among the three polymorphisms, each polymorphism significantly affects serum MBL levels independently. However, there were no significant differences between asthmatics and controls in MBL2 genotype distribution and in MBL concentrations [1.47±0.07(SE) mg/L for asthmatics and 1.66±0.14 mg/L for controls, P=0.2]. MBL levels and genotype have no significant relationship with serum IgE, pulmonary functions, and the severity of asthma.
Conclusion Although plasma MBL levels depend on the MBL2 polymorphisms, these polymorphisms and plasma MBL levels are not associated with the asthma phenotype.