Assessing airway inflammation: from guessing to quantitative measurements

Diagnosing asthma and following the response to treatment have relied on lung function measurements. Improved knowledge of the cellular events leading to airflow limitation has led to new clinical methods to assess the inflammatory component of the disease. Induced sputum analysis and exhaled nitric oxide (NO) measurements are already tools for clinical practice. New cell-specific inflammatory markers and further innovations in the testing of exhaled air, e.g. breath condensates and technical development of simple methods and devices, will also benefit the busy practitioner in near future. Assessing airway inflammation by quantitative measurements, instead of guessing, will also strengthen the role of anti-inflammatory medication as first-line treatment of asthma, even in its mildest forms.