GRANULOMATOUS PNEUMOCYSTIS-CARINII PNEUMONIA - DNA AMPLIFICATION STUDIES ON BRONCHOSCOPIC ALVEOLAR-LAVAGE SAMPLES

Three HIV positive subjects presented with symptoms and radiographic c hanges suggestive of Pneumocystis carinii pneumonia. Methenamine silve r staining of bronchoscopic alveolar lavage (BAL) fluid was negative ( from one sample in one patient and two samples in the other two patien ts). Open lung biopsy was performed because of uncertain clinical prog ress and diagnosis; all three patients were found to have multiple pul monary granulomata encasing numerous P carinii organisms. DNA amplific ation, using P carinii specific oligonucleotides, was performed on sto red bronchoscopic BAL samples. P carinii specific amplification produc t was detected by ethidium bromide staining after electrophoretic sepa ration on agarose gel in one case, and by the more sensitive technique of oligohybridisation in all three cases. In granulomatous P carinii pneumonia organisms are rarely identified in bronchoscopic alveolar la vage samples using histochemical staining, but are detectable by DNA a mplification, although not at levels which can be readily distinguishe d from low, subclinical infection.