VALUE OF PNEUMOCYSTIS-CARINII ANTIBODY AND ANTIGEN-DETECTION FOR DIAGNOSIS OF PNEUMOCYSTIS-CARINII PNEUMONIA AFTER MARROW TRANSPLANTATION

Abstract

Marrow transplant patients (33) with P. carinii pneumonia were studied to determine the usefulness of antibody [Ab] and antigen [Ag] detection in the diagnosis of pneumocystis infection. Ab against P. carinii was present in 1/2 of all patients tested; changes in Ab titer were not helpful diagnostically. P. carinii Ag was detected by counterimmunoelectrophoresis in the serum of 22 of 28 patients tested. Of 28 patients, 15 had Ag detected before or within 72 h after diagnosis. Ag was present in 35 of 52 marrow transplant patients with viral or idiopathic pneumonia, in 11 of 25 transplant patients with no pneumonia and in 22 of 28 other patients with pulmonary infiltrates. Only 1 of 50 normal marrow donors had detectable antigenemia. Detection of this Ag may not establish the diagnosis of P. carinii pneumonia in absence of other clinical or histologic data. Subclinical infection with this agent may be more common than previously recognized.