Cytological Phenotypes of Spontaneous Sputum in the Assessment of the Presence and Type of Bronchopulmonary Inflammation in Patients with Asthma and Chronic Obstructive Pulmonary Disease

In patients with asthma, when it is combined with chronic bronchitis (CB) and COPD, and in patients with COPD, coughing is often accompanied by the production of sputum. Certainly spontaneously produced sputum is investigated in these cases [1]. However, many patients with chronic inflammatory lung disease do not spontaneously produce sputum [2], so that induced sputum is studied in these cases. In 1989, Gibson PG et al. [3] developed a method of obtaining sputum, based on the inhalation of a hypertonic saline solution. They used a hypertonic solution (4.5% for patients in remission and 0.9% for patients with disease exacerbation), which was delivered to the patient via a nebuliser. Samples of the expectorated sputum were processed and used in cytology and other studies. Sputum induction was successful in 90% of patients [4]. The cytology results of spontaneous and induced sputum samples turned out to be identical [5].