Haemophilus influenzae and smoking-related obstructive airways disease

BACKGROUND: Intralumenal bacteria play a critical role in the pathogenesis of acute infective episodes and airway inflammation. Antigens from colonizing bacteria such as nontypeable Haemophilus influenzae (NTHi) may contribute to chronic lung disease through an immediate hypersensitivity response. The objective of this study was to determine the presence of specific NTHi-IgE antibodies in subjects with chronic bronchitis (CB) and COPD who had smoked. METHODS: Serum, sputum, and saliva samples were collected from subjects with CB and moderate–severe COPD and healthy aged-matched controls. Total IgE and specific NTHi IgE were measured by enzyme linked immmunosorbent assay. Throat swabs were examined for the presence of NTHi. RESULTS: The results demonstrate that: i) specific NTHi IgE antibodies occur at a low level in healthy subjects; ii) those with both CB and moderate–severe COPD have elevated specific NTHi IgE antibody compared with healthy controls, with higher levels in those with most severe disease; iii) IgE levels are greater in those with moderate–severe COPD than in those with CB. They demonstrate specific NTHi IgE antibody is regularly found at higher than normal levels in COPD. CONCLUSION: The detection of IgE antibody to colonizing bacteria in all subjects with CB or moderate–severe COPD identifies a possible mechanism of bronchospasm in these subjects amenable to specific intervention therapy.