Induced sputum versus bronchoalveolar lavage in the diagnosis of Pneumocystis jiroveci pneumonia in human immunodeficiency virus-positive patients

Induced sputum is a useful technique for assessing airway inflammation, but its role in the diagnosis of lung disease in immunosuppressed patients needs further investigation. This study compared the use of induced sputum and BAL in the diagnosis of pneumocystosis, in HIV patients. From January 1, 2001, to December 30,2002, HIV-positive patients older than 14 were evaluated at a hospital in Florianopolis, Santa Catarina, Brazil. Patients with respiratory symptoms for seven days or longer, with a normal or abnormal chest X-ray, and those without respiratory symptoms but with an abnormal chest X-ray, were included in the study. All patients were submitted to clinical, radiological and laboratory evaluation, after which induced sputum and bronchoscopy with bronchoalveolar lavage were carried out. The samples were subjected to the following techniques: Gram and Ziehl-Neelsen staining, quantitative culture growth for pyogenic bacteria, direct staining for fungi, culture growth for mycobacteria and fungi, and Grocott-Gomori staining for Pneumocystis jiroveci, as well as total and differential cell counts. The samples with P.jiroveci were selected, as well as the samples for which no etiologic agents were observed. Forty-five patients with a mean age of 34.6, 38 male and 40 Caucasian, comprised the subjects. Interstitial infiltrate was the most frequent radiological pattern (53.3%). The induced sputum sensitivity was 58.8%, specificity 81.8%, predictive positive value 90.9%, predictive negative value 39.1 % and accuracy 64.4 %, for the diagnosis of pneumocystosis, compared with BAL. Based on these data, induced sputum is a useful technique for the diagnosis of pneumocystosis in HIV patients.