DIAGNOSIS OF PNEUMOCYSTIS-CARINII PNEUMONIA IN AIDS-PATIENTS

Background: Based on the changing disease pattern of human immunodefic iency virus (HIV) associated pulmonary complications we conducted a pr ospective study in order to compare the value of laboratory tests in p atients with Pneumocystis (P.) carinii pneumonia (PCP) and other pulmo nary complications and of different identification methods of P. carin ii in bronchoalveolar lavage fluid (BALF) in PCP patients. Patients an d methods: In 217 HIV-1-infected patients we evaluated the following p arameters: plalelets, serum lactat dehydrogenase (LDH), total serum pr otein (TP), hemoglobin (Hb), and CD4+ and CD8+ T-lymphocyte count. P. carinii was identified in BALF by May Grunwald Giemsa stain (MGG), dir ect immunofluorescence test (DIFT), and polymerase chain reaction (PCR ). We correlated these parameters in patients with a presumptive diagn osis of PCP and compared them with those of patients suffering from ot her pulmonary complications. Results: All patients underwent bronchosc opy. 55 patients (25.3%) had a presumptive diagnosis of PCP. The sensi tivity values of MGG stain, DIFT, and PCR differed considerably (79.1% , 56.1%, and 65.9%, respectively), but specificity values did not (99. 2%, 97.3%, and 98.2%, respectively) as well as accuracy values (93.8%, 86.2%, and 89.7%, respectively). The mean values of platelets, of LDH , and of total serum protein of PCP patients and those of patients wit h other pulmonary diseases differed statistically significant as well as the mean values of these parameters of PCP patients and those of pa tients with bacterial pneumonia. Logistic-regression analysis revealed the number of platelets and the amount of total serum protein as inde pendent, significant prognostic factors. Moreover, each PCP patient ha d a CD4+ T-lymphocyte count of less than 200 cells/mm(3) blood. The CD 4/CD8 ratio of PCP patients was statistically significant lower than t hat of patients with bacterial pneumonia. Conclusions: A detection of P. carinii in BALF is inevitable for a definitive diagnosis of a PCP. The most efficient identification method in this case is the MGG stain . Platelets, total serum protein, and CD4+ T-lymphocyte count should b e included into the criteria for the presumptive diagnosis of PCP.