Diagnosis of acute pulmonary histoplasmosis by antigen detection.

BACKGROUND: Antigen detection, which has proven useful in diagnosis of disseminated histoplasmosis, has not been studied in acute pulmonary histoplasmosis (APH). Because treatment is indicated in most patients with moderately severe or severe APH, antigen detection for rapid diagnosis could be helpful. METHODS: Histoplasma antigen detection was evaluated in 130 patients with APH. RESULTS: Antigenuria was detected in 64.6%, antigenemia in 68.6%, and antibody in 64.3%. If both urine and serum specimens were tested, antigen was detected in 82.8%, of which 45.8% had antigenemia only; and if both antigen and antibody were measured, results were positive in 93.3%, of which antigen only was positive in 35.7%. CONCLUSIONS: Testing for antigenemia, antigenuria, and antibodies using the complement fixation test offers a sensitive, noninvasive method for diagnosis of APH.

Improved detection of Histoplasma antigenemia following dissociation of immune complexes.

The sensitivity for detection of Histoplasma antigen is lower in serum than in urine. In other antigen assays, treatment of serum at 104 degrees C in the presence of EDTA was required for detection of antigenemia. Sensitivity and specificity for detection of Histoplasma antigenemia were examined with or without EDTA heat treatment of the serum using the MVista Histoplasma antigen enzyme immunoassay. A total of 94.6% of serum specimens from patients with AIDS and histoplasmosis that were negative untreated were positive after EDTA-heat treatment. Two-thirds of the negative serum specimens from patients with probable histoplasmosis, based upon clinical suspicion and Histoplasma antigenuria, were positive after heat treatment. Specificity was 99.0% in controls, including healthy subjects and patients in whom histoplasmosis or blastomycosis, were excluded. Precision and reproducibility were good and excellent, respectively. These findings demonstrate improvement in sensitivity without reduction in specificity, precision, or reproducibility after heat-EDTA treatment.

Performance characteristics of the platelia Aspergillus enzyme immunoassay for detection of Aspergillus galactomannan antigen in bronchoalveolar lavage fluid.

We have evaluated the Platelia Aspergillus enzyme immunoassay for detection of galactomannan in bronchoalveolar lavage (BAL) specimens in solid organ transplant patients with aspergillosis. The precision and reproducibility in serum or BAL to which galactomannan was added were similar. Sensitivity was 81.8% in patients with aspergillosis, and specificity was 95.8% in lung transplant patients who underwent BAL for surveillance for infection or rejection. Among transplant controls, positive results were more common in patients (i) who underwent diagnostic BAL performed for evaluation of symptoms or chest computed tomographic abnormalities, (ii) who had undergone lung transplantation, or (iii) who were colonized with Aspergillus. Galactomannan testing in BAL is useful for diagnosis of aspergillosis in transplant patients. The significance of positive results in patients without confirmed aspergillosis requires further evaluation.