False-positive IgM serology in coccidioidomycosis.

The clinical observation has been made that there might be an unacceptable number of false-positive enzyme immunoassay (EIA) test results for IgM among persons suspected of having coccidioidomycosis. Patients with a positive result for IgM by EIA are thought to have a diagnosis of acute coccidioidomycosis. However, this study found that 82% of patients with an IgM-positive and IgG-negative EIA result did not have coccidioidomycosis.

Diagnosis of coccidioidomycosis with use of the Coccidioides antigen enzyme immunoassay.

BACKGROUND: We have previously shown antigenuria in patients with coccidioidomycosis through use of the Histoplasma antigen enzyme immunoassay (EIA), and now we have developed a specific Coccidioides antigen EIA. METHODS: The Coccidioides EIA uses antibodies to Coccidioides galactomannan. The sensitivity of the Coccidioides and Histoplasma EIAs was evaluated in patients with more-severe coccidioidomycosis, and the specificity of these EIAs was evaluated in patients with nonfungal infections, in patients with other endemic mycoses, and in healthy individuals. RESULTS: Among patients in the present study, antigenuria was detected in 70.8% of patients with coccidioidomycosis with use of the Coccidioides EIA and in 58.3% of patients with use of the Histoplasma EIA. Antigenuria was absent in 99.4% of healthy individuals, patients with nonfungal infections, and patients with noninfectious conditions. Cross-reactions with other endemic mycoses were observed in 10.7% of patients. CONCLUSIONS: The Coccidioides EIA has potential to be useful in the rapid diagnosis of more-severe forms of coccidioidomycosis.

Diagnosis of coccidioidomycosis by antigen detection using cross-reaction with a Histoplasma antigen.

BACKGROUND: In 2005, patients with coccidioidomycosis were observed to have positive Histoplasma antigen test results. METHODS: We performed a review of the records of patients with coccidioidomycosis who were under our care who underwent testing for Histoplasma antigen to determine the value of this test in the diagnosis of coccidioidomycosis. Many of the patients were immunosuppressed and critically ill. RESULTS: The Histoplasma antigen test had positive results when urine samples from 11 (58%) of 19 patients who had acute or chronic coccidioidomycosis were tested. The sensitivity was highest for patients who had acute coccidioidomycosis, and antigenuria was detected in 11 (79%) of 14 patients. One patient who had chronic coccidioidomycosis but who had a negative result when a urine sample was tested had antigen detected in bronchoalveolar lavage fluid. CONCLUSIONS: Physicians should be alerted that infections with Coccidioides species may cause positive Histoplasma antigen test results. There is potential for the use of this test in the diagnosis of coccidioidomycosis by taking advantage of this observed cross-reactivity. The greatest benefit appears to be in the population of seriously ill patients with acute pneumonia who live in areas that are endemic for Coccidioides infection.

Coccidioidomycosis A Cause of Sarcoidosis.

BACKGROUND: Sarcoidosis is a granulomatous disease of unknown etiology and coccidioidomycosis is a granulomatous fungal infection endemic to the southwestern United States. Clinical observations on patients with sarcoidosis and coccidioidomycosis simultaneously led to the hypothesis that sarcoidosis can be caused by the fungus Coccidioides. METHODS: Two patients with sarcoidosis and coccidioidomycosis were studied, one prospectively (ie, a patient with sarcoidosis was predicted to develop coccidioidomycosis) and the other retrospectively (ie, a patient with coccidioidomycosis develops sarcoidosis). In addition, a literature review found 5 patients with these 2 diseases, and they were analyzed to establish an archived relationship between the 2 entities. In addition, polymerase chain reaction (PCR) testing for Coccidioides deoxyribonucleic acid (DNA) was performed on tissue from 15 Arizona patients diagnosed with sarcoidosis. RESULTS: Patient 1 was diagnosed with sarcoid in Arizona and followed prospectively. There was no evidence for coccidioidomycosis at diagnosis. This patient was observed for 8 years before he was documented to have disseminated coccidioidomycosis. Patient 2 was retrospectively studied. He was diagnosed with disseminated coccidioidomycosis, but after 3 years, while on antifungal therapy, he developed respiratory failure. A lung biopsy was consistent with sarcoidosis with no evidence of Coccidioides; cultures, histopathology, and serology were all negative. Paradoxically, PCR testing for Coccidioides DNA on tissue taken at the time of the sarcoidosis diagnosis were all negative, including Patient 2 who had proven coccidioidomycosis. CONCLUSIONS: The 2 study patients and 5 case reports from the literature support the hypothesis that Coccidioides can cause sarcoidosis in Arizona. There are similar reports in the literature that Histoplasma can be associated with sarcoidosis. Based on these observations, we propose that sarcoidosis can be caused by endemic fungi in different areas of the United States, coccidioidomycosis in the Southwest and histoplasmosis in the Midwest.