Effect of antibiotics on sputum inflammatory contents in acute exacerbations of bronchiectasis

Abstract

We studied the changes in sputum neutrophil chemotactic activity (NCA) and elastolytic activity (EA) in acute exacerbations of bronchiectasis before and after treatment with oral antibiotics. Twelve patients who chronically produced sputum were assessed in the stable state, and when they subsequently developed symptoms of acute exacerbations, prior to initiation of antibiotics, during 2 weeks of antibiotics, and at 2 and 6 weeks after stopping antibiotics. NCA was measured using modified Boyden's technique with multiwell chemotaxis chamber, and EA with N-succiny-trialanine- p-nitroanilide as elastase substrate. All 12 patients had NCA (49·3 ± 8·69% FMLP response) and EA (50·5 ± 17·1 mU per 100 μl) in their sputum in the stable state. At acute exacerbation, there was significant increase in NCA ( P < 0·001) and EA ( P < 0·05). All responded clinically after 1 week of antibiotics, and this was associated with a decrease in NCA and EA back to the levels in stable state. A further week of antibiotics did not result in further decline of NCA or EA. Three patients had another acute exacerbation clinically between 2–6 weeks after stopping antibiotics and their NCA and EA rose again. In the other nine patients, both NCA and EA at 2 and 6 weeks post-treatment were similar to pre-exacerbation levels. Our findings suggest that short course antibiotics effectively control the upsurge in inflammatory activity in acute axacerbations, but has little effect on chronic airway inflammation. This would challenge the validity of such a treatment strategy which is still the most common in clinical practice, when persistent airway inflammation is believed to lead to progressive lung destruction.