Detection of replication-competent human immunodeficiency virus type 1 (HIV-1) in cultures from patients with levels of HIV-1 RNA in plasma suppressed to less than 500 or 50 copies per milliliter

Raltegravir Inclusion Decreases CD4 T-Cells Intra-Cellular Viral Load and Increases CD4 and CD28 Positive T-Cells in Selected HIV Patients

Raltegravir (RLT) prevents the integration of HIV DNA in the nucleus, but published studies remain controversial, suggesting that it does not decrease proviral DNA. However, there are only a few studies focused on virus-targeted cells. We aimed our study on the impact of RLT inclusion on total intra-cellular viral DNA (TID) in cellular subsets and immune effects in patients with newly acquired undetectable plasmatic viral load (UVL). Six patients having UVL using an antiretroviral combination for 6 months and CD4 T-cells > 350/mL and <500/mL were selected to receive RLT for 3 months from M0 to M3. Patients had 7 sequential viro-immunological determinations from M-1 to M5. Immune phenotypes were determined by flow cytometry and TID quantification was performed using PCR assay on purified cells. TID (median values) at the initiation of RLT in CD4 T-cells was 117 copies/millions of cells, decreased to 27.5 on M3, and remained thereafter permanently under the cut-off (<10 copies/millions of cells) in 4 out of 6 patients. This was associated with an increase of CD4 and CD4 + CD28+ T-cells and a decrease of HLA-DR expression and apoptosis of CD4 T-cells. RLT inclusion led to decreases in the viral load along with positive immune reconstitution, mainly for CD4 T-cells in HIV patients.

TROCAI (tropism coreceptor assay information): a new phenotypic tropism test and its correlation with Trofile enhanced sensitivity and genotypic approaches

The only clinically validated assay available to determine HIV tropism is Trofile, an assay that possesses some limitations. Our first aim was to develop a new phenotypic tropism test (TROCAI [tropism coreceptor assay information]) and to categorize results generated by this test according to the virological response to a short-term exposure to the CCR5 receptor antagonist maraviroc (maraviroc clinical test). Our second aim was to compare TROCAI results to those obtained by Trofile enhanced sensitivity (ES) and to different genotypic algorithms. TROCAI assayed HIV tropism in 33 HIV-infected patient viral isolates obtained from a modified coculture, followed by multiple infection cycles of indicator cells. TROCAI obtained a reportable result in all patients with viral loads of >500 HIV RNA copies/ml and in 3/6 patients with <500 HIV RNA copies/ml (30/33 patients, 91.9%). Patients who responded to maraviroc had an X4-using virus proportion in indicator cell supernatant of 0 to 0.41%. Hence, we used the threshold of 0.5% to categorize TROCAI results as R5 (<0.5%) or dual/mixed (>0.5%). The concordance between TROCAI and Trofile (ES) was 22/24 (91.6%), and with genotypic approaches it was 22/26 (84.6%). TROCAI results, which were categorized in this study by the maraviroc clinical test, could be used as a test in addition to those currently used to select patients for treatment with CCR5 antagonists.

Recovery of replication-competent residual HIV-1 from plasma of a patient receiving prolonged, suppressive highly active antiretroviral therapy

The clinical significance of persistent residual viremia in patients on prolonged highly active antiretroviral therapy (HAART) is not clear. Moreover, it remains to be demonstrated whether residual viremia consists of viruses capable of spreading infection in vivo upon termination of therapy. Using residual viral RNAs (vRNAs) isolated from a HAART-treated patient's plasma, we cloned full-length viral genomes and found that most of them could produce infectious, replication-competent HIVs when transfected into TZM-bl cells, suggesting that residual viruses produced in the absence of therapy can initiate fresh cycles of infection and spread in host cells. The data further indicate that residual viremia may pose a major concern with regard to the emergence of drug-resistant HIVs during periods of low adherence to therapy.

Assessing human immunodeficiency virus type 1 tropism: Comparison of assays using replication-competent virus versus plasma-derived pseudotyped virions

Detection of CXCR4-using human immunodeficiency virus by the Trofile assay was compared to that by assays using virus isolates or replication-competent recombinants. Concordance with the Trofile assay was good, but assays using replicating viruses did not increase substantially the ability to detect the presence of CXCR4-using virus.

Pediatric HIV infection: diagnostic laboratory methods

The diagnosis of HIV-1 infection in infants and children continues to present challenges. Currently available virologic assays are sensitive and specific and allow early detection of perinatally acquired HIV infection. Identification soon after birth allows for the rapid initiation of antiretroviral therapy and preservation of the infant's immune system. Serologic diagnostic methods, including HIV-ELISA, Western blot, and immunofluorescence Assay can be used to make the diagnosis of HIV infection in infants older than 18 months of age, children, and adolescents. Recently developed rapid tests allow for testing outside clinical sites, provide results in a short period of time, and allow for prompt initiation of effective prophylaxis in cases of exposure particularly maternal to child transmission. We discuss here the diagnostic management of HIV-exposed infants and HIV-infected children.

TaqMan real-time reverse transcription-PCR and JDVp26 antigen capture enzyme-linked immunosorbent assay to quantify Jembrana disease virus load during the acute phase of in vivo infection

Jembrana disease virus (JDV) is an acutely pathogenic lentivirus that affects Bali cattle in Indonesia. The inability to propagate the virus in vitro has made it difficult to quantitate JDV and determine the kinetics of virus replication during the acute phase of the disease process. We report for the first time two techniques that enable quantification of the virus and the use of these techniques to quantify the virus load during the acute phase of the disease process. A one-step JDV gag [corrected] TaqMan real-time reverse transcription-PCR (RT-PCR) assay was developed for the detection and quantification of JDV RNA in plasma. The limit of detection was 9.8 x 10(2) JDV viral RNA copies over 35 cycles, equivalent to 4.2 x 10(4) JDV genome copies/ml, and a peak virus load of 1.6 x 10(12) during the acute febrile period. An antigen capture enzyme-linked immunosorbent assay (ELISA) was also developed to quantify the levels of JDV capsid (JDVp26) over a linear range of 10 to 200 ng/ml. Viral RNA and JDVp26 levels were correlated in 48 plasma samples obtained from experimentally infected cattle. A significant positive correlation (R = 0.860 and r(2) = 0.740) was observed between the two techniques within the range of their detection limits. The relatively insensitive capture ELISA provides an economical and feasible method for monitoring of virus in the absence of more sensitive techniques.

The contribution of monocyte infection and trafficking to viral persistence, and maintenance of the viral reservoir in HIV infection

Cellular viral reservoirs and anatomic sanctuary sites allow continuing HIV-1 replication in patients with suppressed plasma viremia who are receiving highly active antiretroviral therapy and prevent eradication of HIV-1 by these regimens. Cells of macrophage lineage, including monocytes subsets within the blood, play a role in HIV-1 persistence. Evidence of sequence evolution in blood monocytes, in comparison to resting CD4+ T cells, demonstrates their distinct contribution to plasma viremia. There is evidence to suggest that a specific monocyte subset, of CD14loCD16hi phenotype, is more susceptible to HIV-1 infection than the majority of blood monocytes. Trafficking of monocytes through various tissues following their emigration from the bloodstream allows these cells to differentiate into tissue macrophages, or potentially to egress from the tissues as migratory dendritic cells. This review provides an evaluation of the contribution of monocytes to HIV-1 persistence and the HIV-1 reservoir, essential for the effective design of therapeutic eradication strategies.

Detection of infectious human immunodeficiency virus type 1 in female genital secretions by a short-term culture method

Infectious human immunodeficiency virus type 1 (HIV-1) is difficult to detect in female genital secretions by standard virus culture techniques. To improve detection of cell-free HIV-1 in female genital secretions, we adapted a short-term assay that uses the multinuclear-activation galactosidase indicator (MAGI) assay. When vaginal lavages from HIV-1-infected women were tested with the adapted MAGI assay, 25 (64%) of 39 lavages with detectable, cell-free HIV-1 RNA were shown to have infectious virus. No infectious virus was found in 10 vaginal lavages from HIV-1-infected women with undetectable vaginal viral loads. Significantly (P < 0.01) more lavages from HIV-1-infected women tested positive for infectious virus by the MAGI assay than by standard peripheral blood mononuclear cell (PBMC) coculture, which detected infectious virus in only 6 (17%) of 35 vaginal lavages. Lavages with viral loads of >10,000 copies per lavage yielded significantly (P < 0.01) more positive cultures than those with <10,000 copies by using the MAGI assay. Detection of infectious HIV-1 in vaginal lavages was not associated with the presence of genital tract infections or CD4(+)-T-cell counts. However, although the results were not significant (P = 0.08), the MAGI assay detected infectious virus from more vaginal lavages at a vaginal pH of >/=4.5 than at a pH of <4.5. These results indicate that the MAGI assay is more sensitive than PBMC culture methods for detecting infectious virus in female genital secretions. Accurate measurements of infectious virus in genital secretions will improve studies that evaluate sexual transmission of HIV-1.