British Thoracic Society guideline for bronchiectasis in adults.

The full British Thoracic Society Guideline for Bronchiectasis in Adults is published in Thorax. The following is a summary of the recommendations and good practice points. The sections referred to in the summary refer to the full guideline. The appendices are available in the full guideline.

Increased severity of respiratory infections associated with elevated anti-LPS IgG2 which inhibits serum bactericidal killing.

Although specific antibody induced by pathogens or vaccines is a key component of protection against infectious threats, some viruses, such as dengue, induce antibody that enhances the development of infection. In contrast, antibody-dependent enhancement of bacterial infection is largely unrecognized. Here, we demonstrate that in a significant portion of patients with bronchiectasis and Pseudomonas aeruginosa lung infection, antibody can protect the bacterium from complement-mediated killing. Strains that resist antibody-induced, complement-mediated killing produce lipopolysaccharide containing O-antigen. The inhibition of antibody-mediated killing is caused by excess production of O-antigen-specific IgG2 antibodies. Depletion of IgG2 to O-antigen restores the ability of sera to kill strains with long-chain O-antigen. Patients with impaired serum-mediated killing of P. aeruginosa by IgG2 have poorer respiratory function than infected patients who do not produce inhibitory antibody. We suggest that excessive binding of IgG2 to O-antigen shields the bacterium from other antibodies that can induce complement-mediated killing of bacteria. As there is significant sharing of O-antigen structure between different Gram-negative bacteria, this IgG2-mediated impairment of killing may operate in other Gram-negative infections. These findings have marked implications for our understanding of protection generated by natural infection and for the design of vaccines, which should avoid inducing such blocking antibodies.

Bronchiectasis in older patients with chronic obstructive pulmonary disease : prevalence, diagnosis and therapeutic management.

The prevalence of chronic obstructive pulmonary disease (COPD) increases with age. Recent evidence suggests that the finding of co-existent bronchiectasis is becoming increasingly common, possibly because of increased use of high-resolution CT scanning in the assessment of patients with COPD. This may represent a distinct phenotype of COPD, but, nevertheless, it is likely to pose an increased burden to health services and challenges in determining the correct management of these patients. Here, we review the factors associated with bronchiectasis in older patients with COPD and the evidence for many of the therapies currently used in the treatment of patients, providing a rational approach to their management.

Immunity and bacterial colonisation in bronchiectasis.

BACKGROUND: Non-cystic fibrosis bronchiectasis is characterised by irreversibly dilated bronchi usually associated with chronic sputum production, bacterial colonisation of the lower respiratory tract, inflammation and frequent exacerbations. Irrespective of the underlying cause, this represents failure of the host defence to maintain sterility of the respiratory tract. OBJECTIVE: To review the interactions and associations of non-cystic fibrosis bronchiectasis with the inate and adaptive immune systems with particular emphasis on known failure of local defences established deficiencies of the adaptive immune system. In addition we wished to explore potential subtle changes in the host defence which can lead to bacterial colonisation together with bacterial factors that aid colonisation of the lower respiratory tract and impair antibiotic response. This latter concept is considered with particular reference to Pseudomonas aeruginosa, which is often found in the airway secretions of patients with non-cystic fibrosis bronchiectasis and may act as a model for other organisms. METHODS: An extensive literature review was undertaken to provide a comprehensive review of immunity and bacterial colonisation in non-cystic fibrosis bronchiectasis, with focus on in vitro studies examining bacterial factors which may facilitate colonisation together with potential implications for management. CONCLUSION: These themes provide a review of the current understanding of non-cystic fibrosis bronchiectasis together with areas for future research and potential therapeutic strategies.