Current methodology for the diagnosis of infection with Pneumocystis carinii (PC) relies on demonstration of organisms with typical morphology using special stains such as methenamine-silver, toluidine blue-O, etc. None of these stains are specific and they all must be interpreted with caution since yeast-like organisms or cellular materials can sometimes mimic the appearance of PC. Specific histologic staining using antibody directed against PC has not been possible due to the lack of appropriate antibody. One of us has produced monoclonal antibody preparations directed against human PC. These antibodies are being used to develop a specific fluorescent antibody stain to be used to aid in the diagnosis of PC pneumonia. Bronchial lavage specimens are being tested in parallel by traditional toluidine blue-O stain and by a monoclonal antibody indirect immunofluorescence procedure. We will also be developing an immunoperoxidase stain using the same entibody preparations.
