In 1995, the U.S. Public Health Service (USPHS) and the Infectious Diseases Society of America (IDSA) developed guidelines for preventing opportunistic infections (OIs) among persons infected with human immunodeficiency virus (HIV); these guidelines were updated in 1997 and 1999. This fourth edition of the guidelines, made available on the Internet in 2001, is intended for clinicians and other health-care providers who care for HIV-infected persons. The goal of these guidelines is to provide evidence-based guidelines for preventing OIs among HIV-infected adults and adolescents, including pregnant women, and HIV-exposed or infected children. Nineteen OIs, or groups of OIs, are addressed, and recommendations are included for preventing exposure to opportunistic pathogens, preventing first episodes of disease by chemoprophylaxis or vaccination (primary prophylaxis), and preventing disease recurrence (secondary prophylaxis). Major changes since the last edition of the guidelines include 1) updated recommendations for discontinuing primary and secondary OI prophylaxis among persons whose CD4+ T lymphocyte counts have increased in response to antiretroviral therapy; 2) emphasis on screening all HIV-infected persons for infection with hepatitis C virus; 3) new information regarding transmission of human herpesvirus 8 infection; 4) new information regarding drug interactions, chiefly related to rifamycins and antiretroviral drugs; and 5) revised recommendations for immunizing HIV-infected adults and adolescents and HIV-exposed or infected children.

The Coccidioides EIA has potential to be useful in the rapid diagnosis of more-severe forms of coccidioidomycosis.

We observed false-positive results in the Platelia Aspergillus enzyme-linked immunoassay (EIA) for specimens from patients with histoplasmosis and mice with experimental infection. Platelia Aspergillus EIA-positive specimens were negative in the second-generation Histoplasma antigen EIA. Care must be taken to exclude histoplasmosis for patients with positive Platelia Aspergillus EIA results.The Platelia Aspergillus enzyme-linked immunoassay (EIA) detects a galactomannan antigen produced by several molds (5). However, studies to date have not included Histoplasma capsulatum. We recently observed false-positive results in the Platelia Aspergillus EIA for specimens from six patients with culture-proven histoplasmosis, as have others (4). Based upon these observations (Table 1), we conducted a laboratory-based study of specimens submitted for Platelia Aspergillus EIA or Histoplasma antigen testing and evaluated cross-reactivity in experimental models of histoplasmosis and aspergillosis.(Part of this work was presented at the 46th Interscience Conference on Antimicrobial Agents and Chemotherapy, 27 to 30 September 2006.)Residual serum and bronchoalveolar lavage (BAL) fluid specimens that were submitted to MiraVista Diagnostics for Histoplasma antigen testing or Platelia Aspergillus EIA and were positive were retested the following day in the other EIA. The second-generation Histoplasma antigen EIA (MiraVista Diagnostics, Indianapolis, IN) uses polyclonal antibodies to H. capsulatum and has been described elsewhere (6). Results of Ն1 unit were regarded as positive. The Platelia Aspergillus EIA (Bio-Rad Laboratories, Redmond, WA) uses monoclonal antibodies produced against Aspergillus fumigatus. Specimens were pretreated with EDTA for the Platelia Aspergillus EIA and boiled in accordance with the manufacturer's specifications. Results with a galactomannan index (GMI) of 0.5 or greater were reported as positive. Note that the Platelia Aspergillus EIA is not FDA cleared for specimens other than serum.Twenty-three of 48 serum specimens positive for antigen in the second-generation Histoplasma antigen EIA were positive in the Platelia Aspergillus EIA (Fig. 1). Positive results were more frequent for specimens giving levels of 40 units or higher in the Histoplasma antigen EIA (12/17 [70.6%]) than for those giving levels below 40 units (11/31 [35.5%]) (P ϭ 0.043 by chi-square test). As controls, 12 serum specimens that were negative in the Histoplasma antigen EIA were tested in the Platelia Aspergillus EIA, and all were negative. Seven of 11 (63.6%) BAL fluid specimens that were positive in the Histoplasma antigen EIA were positive in the Platelia Aspergillus EIA. Results for the Histoplasma antigen EIA ranged from 2.2 to 61.7 units for the BAL fluid specimens that were positive in the Platelia Aspergillus EIA, compared to 4.2 to 21.2 units for those that were negative. Ten control BAL fluid specimens that were negative in the Histoplasma antigen EIA were negative in the Platelia Aspergillus EIA.Twenty serum specimens that w...