Mannose-binding lectin deficiency and acute exacerbations of chronic obstructive pulmonary disease

Background: Mannose-binding lectin is a collectin involved in host defense against infection. Whether mannose-binding lectin deficiency is associated with acute exacerbations of chronic obstructive pulmonary disease is debated. Methods: Participants in a study designed to determine if azithromycin taken daily for one year decreased acute exacerbations had serum mannose-binding lectin concentrations measured at the time of enrollment. Results: Samples were obtained from 1037 subjects (91%) in the trial. The prevalence of mannose-binding lectin deficiency ranged from 0.5% to 52.2%, depending on how deficiency was defined. No differences in the prevalence of deficiency were observed with respect to any demographic variable assessed, and no differences were observed in time to first exacerbation, rate of exacerbations, or percentage of subjects requiring hospitalization for exacerbations in those with deficiency versus those without, regardless of how deficiency was defined. Conclusion: In a large sample of subjects with chronic obstructive pulmonary disease selected for having an increased risk of experiencing an acute exacerbation of chronic obstructive pulmonary disease, only 1.9% had mannose-binding lectin concentrations below the normal range and we found no association between mannose-binding lectin concentrations and time to first acute exacerbation or frequency of acute exacerbations during one year of prospective follow-up.