Clinical effects of purified air administered to the breathing zone in allergic asthma: A double-blind randomized cross-over trial.

BACKGROUND: Exposure to inhaled allergens is a pathogenetic factor in allergic asthma. However, most studies that previously looked at air cleaning devices have shown little or no effect on patients with perennial allergic asthma. AIMS AND OBJECTIVES: We examined a novel treatment using temperature regulated laminar airflow with a very low particle concentration directed to the breathing zone of teenagers and young adults with mild to moderate allergic asthma during night sleep. We hypothesised that the decreased allergen exposure during the night would have an effect on bronchial inflammation and quality of life. METHOD: Twenty-two patients (mean 18.8 years) were randomized to start with active or placebo treatment for 10 weeks. All patients received both active and placebo treatment with unfiltered air, with a 2-week wash-out period in between treatments. Maintenance treatment with inhaled corticosteroids was unaltered during the trial period. Health related quality of life (miniAQLQ) was the primary effectiveness measure. Exhaled nitric oxide (FeNO) and spirometry were also investigated. RESULTS: Active treatment resulted in an improved miniAQLQ compared to placebo (mean score 0.54, p<0.05, n=20). An effect on bronchial inflammation was also detected with significantly lower FeNO values during the active treatment period (mean -6.95 ppb, p<0.05, n=22). Both effects were evident after 5 weeks. The change in lung function was not statistically significant. CONCLUSION: Clean air, administered directly to the breathing zone during sleep, can have a positive effect on bronchial inflammation and quality of life in patients with perennial allergic asthma.

Exhaled breath condensate and serum levels of hepatocyte growth factor in pneumonia.

Hepatocyte growth factor (HGF) is a protein produced by mesenchymal cells in many organs, which can stimulate epithelial growth. An enhanced production and concentration of HGF is observed after injuries. The lung is one of the major sources of HGF. By cooling exhaled air, a condensate is formed containing molecules from bronchi and alveoli. In order to investigate HGF-concentration and time course in pneumonia, paired serum and exhaled breath condensate was collected from 10 patients with pneumonia, 10 patients with non-respiratory infections and 11 healthy controls. The concentration of HGF was measured by an immunoassay kit. In the acute phase HGF-levels in breath condensate and serum were significantly higher in the patients with pneumonia compared to the control groups. Similar concentrations in breath condensate were seen in healthy controls and in patients with non-respiratory infections. In the patients with pneumonia a decrease in serum HGF was seen already after 4-7 days while HGF values in breath condensate remained elevated even after 4-6 weeks. These results might imply local product on of HGF in the lungs and a long repair and healing process after pneumonia.