Failure of the cryptococcal serum antigen test to detect primary pulmonary cryptococcosis in patients infected with human immunodeficiency virus [letter]

Of 28 HIV-positive patients from the Centre Hospitalier de Kigali, Rwanda, diagnosed as having pulmonary cryptococcosis (PC) during Jan. 1990-Mar. 1992, 24 had been screened for cryptococcal serum antigen (CSA). Cryptococcus neoformans was isolated from bronchoalveolar lavage fluid (18 patients), pleural effusion fluid (2), sputum (3) and pulmonary specimens obtained by needle aspiration (1). Typical encapsulated yeasts were found in transbronchial lung biopsy specimens from 4 patients and from a bronchial biopsy specimen in 1 patient. Eight patients had concomitant meningoencephalitic cryptococcosis and 1 had disseminated cryptococcosis without meningeal involvement. The CSA test was positive for only 9 patients, of whom all had a concomitant extrapulmonary site of cryptococcal infection. Cryptococcal antigen was not detected in any of the 15 patients with primary PC. It is concluded that screening for CSA with a latex agglutination test does not facilitate the diagnosis of PC without extrapulmonary cryptococcal involvement, although this test may be easier and faster than culture for the early diagnosis of extrapulmonary cryptococcosis