ANALYSIS OF PNEUMOCYSTIS-CARINII ORGANISM BURDEN, VIABILITY AND ANTIGENS IN BRONCHOALVEOLAR LAVAGE FLUID IN AIDS PATIENTS WITH PNEUMOCYSTOSIS - CORRELATION WITH DISEASE SEVERITY

Objectives: We examined 96 bronchoalveolar lavage fluid (BALF) specime ns from AIDS patients with proven Pneumocystis carinii pneumonia (PCP) in order to compare the relationship of organism burden, viability an d antigen expression with disease severity at the time of clinical pre sentation. Methods: Tinctorial analysis of BALF specimens with proven PCP using Diff-Quik, cresyl echt violet and erythrosin B stains to eva luate organism burden and viability. P. carinii antigen examination wa s performed by Western blot analysis. Results: P. carinii cluster rati os were more sensitive than cyst counts as an indicator of organism bu rden, and correlated well with the alveolar-arterial oxygen gradient a s a measure of disease severity. Erythrosin B, the vital stain used to measure P. carinii viability, displayed a wide range of values and pr ovided little useful information. Antigens of 35-45 and 95 kD, which w ere specific for P. carinii, were found by immunoblot analysis in BALF cellular fraction of most patients with pneumocystosis. By contrast, antigens of 52 and 66 kD, which were found in both BALF supernatant an d cellular fractions of P. carinii patients and controls, most likely represented albumin and immunoglobulin G heavy chain, respectively, of host origin. The 35-45 kD antigen was found in 88% of the BALF specim ens and appeared to represent an important marker of P. carinii infect ion. The 95 kD antigen was detected in 49% of the specimens. Conclusio ns: We conclude that analysis of P. carinii characteristics in BALF sp ecimens of patients with pneumocystis may provide additional informati on. These data will also be helpful in developing more sensitive assay s and in targeting specific P. carinii factors for future investigatio n.