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Background: Improved tuberculosis (TB) screening is urgently needed for human immunodeficiency virus (HIV) infected patients., Methods: An observational, multi-country, cross-sectional study of HIV-infected patients to compare a standardized diagnostic evaluation (SDE) for TB with standard of care (SOC). SOC evaluations included TB symptom review (current cough, fever, night sweats and/or weight loss), sputum Ziehl-Neelsen staining and chest radiography. SDE screening added extended clinical signs and symptoms and fluorescent microscopy (FM). All participants underwent all evaluations. Mycobacterium tuberculosis on sputum culture was the primary outcome., Results: A total of 801 participants were enrolled from Botswana, Malawi, South Africa, Zimbabwe, India, Peru and Brazil. The median age was 33 years; 37% were male, and median CD4 count was 275 cells/mm(3). Thirty-one participants (4%) had a positive culture on Löwenstein-Jensen media and 54 (8%) on MGIT. All but one positive culture came from sub-Saharan Africa, where the prevalence of TB was 54/445 (12%). SOC screening had 54% sensitivity (95%CI 40-67) and 76% specificity (95%CI 72-80). Positive and negative predictive values were respectively 24% and 92%. No elements of the SDE improved the predictive values of SOC., Conclusions: Symptom-based screening with smear microscopy was insufficiently sensitive. More sensitive diagnostic testing is required for HIV-infected patients.

To be successful with strategies involving passive immunization or the generation of neutralizing antibodies against HIV, it is crucial that we improve our understanding of the process of antibody-mediated HIV neutralization. We have used a neutralization assay based on polymerase chain reaction (PCR) that is more rapid and sensitive than the conventional p24 neutralization assay based on enzyme-linked immunosorbent assay (ELISA). PCR assays permit measurement of the number of infectious events and can detect small amounts of HIV-1 only a few days postinfection. In these studies, the human anti-V3 monoclonal antibody 694/98-D was used to neutralize the infectivity of the laboratory isolate HIVIIIB for CEM-SS cells. 8E5/LAV cells, which contain a single integrated copy of proviral DNA per cell, served as a standard to determine the amount of HIV-1 copies in infected CEM-SS cells. Evaluation of antibody-mediated neutralization was possible at 2 to 3 days postinfection, at a time when p24 readouts were not conclusive. We achieved >95% neutralization of HIVIIIB, and of its molecular clone HXB2, using the monoclonal antibody 694/98-D. This degree of neutralization is probably highly significant in vivo. Nevertheless, a small amount of both HIVIIIB and HXB2 ( approximately 5%) escapes neutralization and can consistently be detected after a few days by this sensitive assay. Experiments with different anti-HIV monoclonal antibodies and viruses showed that the assay could be applied to anti-V3 as well as anti-CD4 binding domain antibodies as well as HIV laboratory strains or primary isolates.