HIV-1 ICD p24 antigen detection in ugandan infants: use in early diagnosis of infection and as a marker of disease progression.

The objective of this study was to determine the use of immune-complex dissociated (ICD) p24 antigen detection for the diagnosis and prognosis of HIV-1 infection in Ugandan children. Plasma collected prospectively from children born to HIV-1 infected Ugandan women was stored and later analyzed for the presence of neutralizable HIV-1 p24 antigen using the Coulter ICD p24 antigen and neutralization kits. HIV-1 infection status, disease progression, and survival of the children were determined. Specimens from 311 children born to HIV-1 infected women, including 138 HIV-1 infected children, and 113 children born to negative women were tested. Sixty-nine (50%) infected children were p24 antigen positive at least once. For early HIV-1 diagnosis, the specificity and positive predictive value of the assay were consistently high (>95% and >83% respectively), but the sensitivity was low (6-53%), especially in the first months of life. The presence of p24 antigenemia in the first two years of life was associated with poor survival (20%) by 80 months of age compared with infected children without antigenemia (43%, P < 0.001). Early detection of p24 antigen (6 months, P < 0.001). The data suggest that ICD p24 antigen detection is not a sensitive method for the determination of infant HIV-1 status in our cohort of HIV-1 infected Ugandan children tested in the first two years of life. There was a strong correlation, however, between the presence and time of onset of p24 antigenemia and mortality among HIV-1 infected children.

Detection of human immunodeficiency virus type 1 (HIV-1) DNA and RNA sequences in HIV-1 antibody-positive blood donors in Uganda by the Roche AMPLICOR assay.

The ability of commercially available PCR-based assays to accurately detect or quantitate human immunodeficiency virus type 1 (HIV-1) DNA or RNA in individuals predominantly infected with HIV-1 subtypes A and D is not known. Therefore, peripheral leukocytes from 43 individuals in Kampala, Uganda, positive for HIV by the Western blot (immunoblot) assay were tested by using the Roche AMPLICOR HIV-1 assay for the detection of DNA gag sequences. Plasma from these same individuals was tested by using the Roche HIV-1 AMPLICOR MONITOR HIV-1 assay for the quantitation of HIV-1 RNA gag sequences. In addition, peripheral leukocytes were tested for HIV-1 DNA by using a lower annealing temperature or a different primer pair for the HIV-1 pol region. The proportions of individuals with detectable HIV-1 DNA and RNA gag sequences by the Roche assays were 74 and 90%, respectively. The proportions positive for HIV-1 DNA sequences by using a 50 degrees C annealing temperature or the pol primer pair were 71 and 98%, respectively. In summary, the standard Roche assay did not detect HIV-1 DNA sequences in a significant number of HIV-1-infected individuals in Uganda. However, use of a pol primer pair increased the sensitivity of the assay to 98%. The sensitivity of the Roche AMPLICOR MONITOR assay for the detection and quantitation of HIV-1 RNA sequences was significantly higher than that of the DNA-based assay, but the efficiency of the assay, and hence, the accuracy of the values obtained with RNA, is not known. Modifications to existing assays are needed to enhance the sensitivities and accuracies of these commercially available assays for use in developing countries where non-B HIV-1 subtypes predominate.

Detection of human immunodeficiency virus type 1 (HIV-1) DNA and p24 antigen in breast milk of HIV-1-infected Ugandan women and vertical transmission.

OBJECTIVE: To determine the correlation between the detection of human immunodeficiency virus type 1 (HIV-1) in breast milk, the duration of breastfeeding, and vertical transmission of HIV-1 infection in Ugandan women. METHODS: A prospective study of HIV-1 infection in pregnant Ugandan women and their infants has been ongoing since 1990 with follow-up of mother-infant pairs for at least 2 years. Expressed breast milk specimens were collected from 201 HIV-1-seropositive and 86 HIV-1-seronegative Ugandan women approximately 6 weeks after delivery. The presence of HIV-1 DNA in the cellular fraction of the breast milk was detected by polymerase chain reaction (PCR), and HIV-1 p24 antigen was detected in the cell-free breast milk supernatant using p24 antigen enzyme immunoassay (EIA) after immune complex dissociation (ICD). The duration of breastfeeding and the clinical status of the mothers and their children were recorded. HIV-1 EIA, Western blot, PCR, or p24 antigen detection were used for the determination of the HIV-1 infection status of the children. RESULTS: Of the 201 HIV-1-infected women studied, 47 had HIV-1-infected children, 143 had children who seroreverted, and 11 had children of indeterminate status. Breast milk supernatants were available for ICD p24 antigen testing from 188 of the HIV-1-infected women and none had detectable p24 antigen. Breast milk cell pellets were available and contained amplifiable DNA in 125 of the HIV-1-infected women (20 transmitters, 104 nontransmitters, 1 indeterminate). HIV-1 DNA was detected by PCR in 72% (75/104) of nontransmitters and 80% (16/20) of the transmitters. The duration of breastfeeding by transmitter mothers (15.8 months) was not significantly different from nontransmitter mothers (14.4 months). CONCLUSIONS: No correlation was found between the detection of HIV-1 in breast milk or the duration of breastfeeding and transmission of HIV-1 infection in this study of Ugandan women.

Effect of specimen storage on absolute CD4 counts.

We have evaluated the effect of specimen storage on absolute CD4 counts by a commercially available manual assay. This assay utilizes latex particles coated with CD4 monoclonal antibodies that are mixed with lymphocytes in whole blood. Thirty blood samples were analyzed on days 1, 2, 4, and 7 postcollection. Linear regression analysis and Pearson correlation coefficients were used to determine the relationship between the absolute CD4 count and the storage time after sample collection. There was a significant decrease in absolute CD4 counts from baseline over time, dropping 3.6% at day 2, 10.1% at day 4, and 18.8% at day 7. However, the standard error of the B coefficient was constant [SE (B) = 0.031] up to day 4, indicating that reliable estimates of the baseline CD4 counts could be made from the CD4 counts determined up to day 4 from the time of sample collection. In addition to being sample, rapid, and inexpensive, the manual assay is capable of giving a reliable absolute CD4 count after specimen storage of up to 4 days. The application of this assay in the limited facilities of developing countries' laboratories is attractive.

Reduced sensitivity of tuberculosis serodiagnosis in patients with AIDS in Uganda.

SETTING: The diagnostic utility of serodiagnosis of tuberculosis in HIV-infected persons was studied in Kampala, Uganda. OBJECTIVE: This study was undertaken to evaluate the utility of a recently described serologic assay for the diagnosis of tuberculosis in HIV-infected patients. DESIGN: The study was undertaken as a cross-sectional survey of 349 subjects, including human immunodeficiency virus-infected and uninfected patients with tuberculosis and control subjects. Serum from each subject was assayed by enzyme-linked immunosorbent assay (ELISA) for IgG antibody to the 30,000 dalton antigen of Mycobacterium tuberculosis. RESULTS: Test sensitivity dropped from 0.62 in non HIV-infected tuberculous patients to 0.28 in HIV-infected patients. CONCLUSIONS: ELISA serodiagnosis of tuberculosis may have a markedly decreased utility in populations where HIV infection is prevalent.

Influence of tuberculosis on human immunodeficiency virus (HIV-1): enhanced cytokine expression and elevated beta 2-microglobulin in HIV-1-associated tuberculosis.

Tuberculosis results in activation of T cells and macrophages that may harbor latent human immunodeficiency virus (HIV-1). Although such activation is beneficial to the host in terms of mycobacterial disease, it may be deleterious in terms of HIV-1. In Ugandan HIV-1-seropositive patients with pulmonary tuberculosis, antigen-induced blastogenesis and production of tumor necrosis factor-alpha (a cytokine that induces expression of HIV-1 in latently infected cells) were 3-10 times greater than in controls. The mean serum beta 2-microglobulin level was 5.22 mg/L in recently diagnosed patients, significantly greater than levels in HIV-negative patients with tuberculosis or asymptomatic HIV-1-seropositive subjects. beta 2-microglobulin was significantly lower in subjects who had completed at least 2 months of antituberculous therapy. These observations suggest that HIV-1-associated tuberculosis is accompanied by immune activation that may result in increased HIV expression and accelerated progression to AIDS.