Search

The accuracy of diagnostic tests for HIV in patients with tropical infections is poorly documented. Human African trypanosomiasis (HAT) is characterized by a polyclonal B-cell activation, constituting a risk for false-positive reactions to diagnostic tests, including HIV tests. A retrospective study of the accuracy of HIV diagnostic tests was performed with 360 human African HAT patients infected with Trypanosoma brucei gambiense before treatment and 163 T. b. gambiense-infected patients 2 years after successful treatment in Mbuji Mayi, East Kasai, Democratic Republic of the Congo. The sensitivities, specificities, and positive predictive values (PPVs) of individual tests and algorithms consisting of 3 rapid tests were determined. The sensitivity of all tests was 100% (11/11). The low specificity (96.3%, 335/348) and PPV (45.8%, 11/24) of a classical seroconfirmation strategy (Vironostika enzyme-linked immunosorbent assay [ELISA] followed by line immunoassay) complicated the determination of HIV status, which had to be determined by PCR. The specificities of the rapid diagnostic tests were 39.1% for Determine (136/348); 85.3 to 92.8% (297/348 to 323/348) for Vikia, ImmunoFlow, DoubleCheck, and Bioline; and 96.6 to 98.3% (336/348 to 342/348) for Uni-Gold, OraQuick, and Stat-Pak. The specificity of Vironostika was 67.5% (235/348). PPVs ranged between 4.9 and 64.7%. Combining 3 different rapid tests resulted in specificities of 98.3 to 100% (342/348 to 348/348) and PPVs of 64.7 to 100% (11/17 to 11/11). For cured HAT patients, specificities were significantly higher for Vironostika, Determine, Uni-Gold, and ImmunoFlow. T. b. gambiense infection decreases the specificities of antibody detection tests for HIV diagnosis. Unless tests have been validated for interference with HAT, HIV diagnosis using classical algorithms in untreated HAT patients should be avoided. Specific, validated combinations of 3 HIV rapid tests can increase specificity.

In order to evaluate alternative tests and strategies to simplify pediatric human immunodeficiency virus (HIV) screening at the district hospital level, a cross-sectional exploratory study was organized in the Democratic Republic of the Congo. Venous and capillary phlebotomies were performed on 941 Congolese children, aged 1 month to 12 years (153 children under 18 months and 788 children more than 18 months old). The HIV prevalence rate was 4.7%. An algorithm for children more than 18 months old, using serial rapid tests (Determine, InstantScreen, and Uni-Gold) performed on capillary blood stored in EDTA tubes, had a sensitivity of 100.0% (95% confidence interval [CI], 88.9 to 100.0%) and a specificity of 100.0% (95% CI, 99.5 to 100.0%). The results of this study suggest that the ultrasensitive p24 antigen assay may be performed on capillary plasma stored on filter paper (sensitivity and specificity, 100.0%; n=87) instead of venous plasma (sensitivity, 92.3%; specificity, 100.0%; n=150). The use of glucolets (instruments used to perform capillary phlebotomies), instead of syringes and needles, may reduce procedural pain and the risk of needle stick injuries at a comparable cost. Compared to the reference, HIV could have been correctly excluded based on one rapid test for at least 90% of these children. The results of this study point towards underutilized opportunities to simplify phlebotomy and pediatric HIV screening.

Objectives In 2011, a consensus was reached defining 'late presenters' ( LPs) as individuals presenting for care with a CD4 count < 350 cells/μL or with an AIDS-defining event, regardless of CD4 count. However, a transient low CD4 count is not uncommon in recent infections. The objective of this study was to investigate how measurements of late presentation change if the clinical stage at the time of diagnosis is taken into account. Methods Case surveillance data for newly diagnosed patients in Belgium in 1998-2012 were analysed, including CD4 count at diagnosis, the presence of AIDS-defining events, and recent infections (< 6 months) as reported by clinicians in the case of acute illness or a recent negative test. First, proportions of LPs were calculated according to the consensus definition. Secondly, LPs were reclassified as 'nonlate' if infections were reported as recent. Results A total of 7949 HIV diagnoses were included in the study. Recent infections were increasingly reported over time, accounting for 8.2% of new infections in 1998 and 37.5% in 2012. The consideration of clinical stage significantly modified the proportion of LPs: 18.2% of men who have sex with men ( MSM) diagnosed in 2012 would be classified as LPs instead of 30.9% using the consensus definition ( P < 0.001). The proportion of patients misclassified as LPs increased significantly over time: 5% in MSM in 1998 vs. 41% in 2012. Conclusions This study suggests that low CD4 counts in recent infections may lead to overestimation of late presentation when applying the consensus definition. The impact of transient CD4 count on late presentation estimates should be assessed and, if relevant, the introduction of clinical stage in the definition of late presentation should be considered. [ABSTRACT FROM AUTHOR]

Highlights: [•] Oral fluid specimens were adapted and evaluated using conventional commercially HIV tests. [•] Three conventional ELISAs of which two adapted for use with oral fluid, were evaluated. [•] Storage of the oral fluid samples for 7 days at ambient temperature was validated. [•] A testing algorithm for HIV surveillance and for screening was proposed. [Copyright &y& Elsevier]

Objective The aim of the study was to evaluate the use of proviral DNA as a source of viral genetic material for genotypic coreceptor tropism testing (GTT). Methods GTT consisted of bulk V3 sequencing followed by geno2pheno interpretation with the interpretative cut-off [false positive rate (FPR)] set at 5 and 10%. GTT was performed for 165 patients with a viral load of >500 HIV-1 RNA copies/mL on simultaneously collected plasma RNA and proviral DNA, and for 126 patients with a viral load of <500 copies/mL on current proviral DNA and pretreatment plasma RNA. Phenotypic tropism testing (PTT) results were available for 142 samples. Results In the simultaneous RNA/DNA comparison, concordance in prediction was 95.2% (at FPR 10%) and 96.4% (at FPR 5%). Six RNA-R5/DNA-X4 and two RNA-X4/DNA-R5 discordances were observed at an FPR of 10%, and six RNA-R5/DNA-X4 discordances were observed at an FPR of 5%. In the longitudinal RNA/DNA comparison, concordance was 88.1% (at FPR 10%) and 90.5% (at FPR 5%). Eight RNA-X4/DNA-R5 and seven RNA-R5/DNA-X4 discordances were seen at an FPR of 10%, and 10 RNA-R5/DNA-X4 and two RNA-X4/DNA-R5 discordances at an FPR of 5%. The overall concordance of RNA GTT with PTT was 82% (at FPR 10%) and 83% (at FPR 5%). The overall concordance of DNA GTT with PTT was 85% (at both 10 and 5% FPRs). Conclusions GTT produced highly concordant tropism predictions for proviral DNA and plasma RNA. GTT on proviral DNA offers a promising approach for tropism prediction in clinical practice, particularly for the assessment of treated patients with low or suppressed viraemia. [ABSTRACT FROM AUTHOR]

Abstract: The performance was assessed of a new, rapid, visual and qualitative immunoassay for the detection of HIV p24 antigen (Ag) and antibodies (Ab) to HIV-1 and HIV-2. Characterised serum or plasma specimens from patients diagnosed with HIV infection were tested: 179 samples of known Ab-positive patients harbouring different subtypes of HIV-1 (n =154) and HIV-2 (n =25) and 200 samples from individuals not infected with HIV. The assay''s Ag sensitivity was assessed by testing HIV seroconversion panels (n =10) and primary HIV infection specimens (n =57). In addition, the influence of the genetic variability of HIV-1 on Ag detection was evaluated using dilutions of culture supernatants infected with different subtypes (n =50). The performance of the rapid test was compared to a “gold standard” testing algorithm with the use of a single Ag ELISA and with the Vironostika® HIV Uni-Form II Ag/Ab test, a fourth-generation ELISA. The new assay, the Determine™ HIV-1/2 Combo demonstrated 100% (98.2–100.0) Ab specificity (200/200) and 100% (98.0–100.0) Ab sensitivity (179/179). In these samples, the observed Ag sensitivity was 86.6% (58/67) with the Determine™ HIV-1/2 Combo test and 92.5% (62/67) with the Vironostika compared to the reference single Ag ELISA. The assay could not detect Ag in one group O, one subtype F and two subtype H cell supernatant isolates. None of the HIV-2 Ag could be detected. [Copyright &y& Elsevier]

Monitoring the efficacy of highly active antiretroviral treatment (HAART) is crucial if disease progression and the emergence of viral mutants are to be avoided. Classical viral load monitoring is too expensive for large-scale use in resource-limited settings. Three alternative measures, CD4 count, total lymphocyte count (TLC) and haemoglobin, were evaluated as surrogate markers of treatment success (viral load below detection level) among 710 HIV-positive patients who started HAART in an HIV treatment centre in Belgium. TLC correlated well with changes in CD4 counts during HAART, but an increase in TLC alone was a poor predictor of treatment success. A combination of increases in both haemoglobin levels and TLC proved a reliable predictor of successful treatment outcome comparable to the increase in CD4 count, but its specificity and sensitivity were low. [ABSTRACT FROM AUTHOR]

Our objective was to study the evolution of CD4 cell count five years after starting highly active antiretroviral treatment (HAART) in a clinical setting. The study was performed at the HIV outpatient clinic, Institute of Tropical Medicine, Antwerp. All patients (n = 225) who started HAART in 1997, who had a CD4 cell count within six months prior to starting HAART and who were subsequently followed for at least two years were included. Change in CD4 cell count after start of HAART and the influence of patient and clinical factors were investigated using graphical exploration, endpoint analysis and mixed-effects linear regression. The mean CD4 cell count at start of HAART was 280 cells/mm3. At the five-year endpoint of the study the mean increase in CD4 cell count was 333 cells/mm3, while 79% of the patients had a viral load less than 400 copies/mL. There was a significant negative correlation between increase in CD4 cell count at five years and time since first positive HIV test at start of HAART (P = 0.021). Patients who ever had a HAART interruption of more than seven days had a significantly lower increase in CD4 cell count than those who did not (225 cells/mm3 compared with 438 cells/mm3; P < 0.001). A mixed-effects linear regression model additionally suggested a significant impact of exposure to antiretrovirals prior to HAART (P = 0.03). Overall, the recovery of CD4 cell count after five years of HAART is good, although therapy interruptions have an important negative impact. [ABSTRACT FROM AUTHOR]

To evaluate the performance of 22 assays for the detection of antibodies to HIV. Twenty-two assays for the combined detection of antibodies to HIV-1 and HIV-2, were evaluated on the same panel of serum specimens of diverse origin. Eight of the assays were ELISAs and the remaining 14 were simple, assays read visually. The specimen panel consisted of anti-HIV positive and negative samples from Africa (n=192), Europe (n=206), Asia (n=99) and Latin America (n=98). In addition to estimations of sensitivity and specificity, the assays were assessed, using a novel scoring system, for their ease of performance and for their suitability for use in small laboratories and clinics. The sensitivities of the assays in terms of seroconversion were assessed using series of specimens collected from nine individuals undergoing seroconversion. Eight ELISAs and eight of 14 simple assays had sensitivities and specificities of >99 and 95%, respectively. The results of these evaluations will be of assistance to those responsible for the selection of appropriate anti-HIV assays according to laboratory circumstances, the purpose of the testing and the population being tested. [Copyright &y& Elsevier]

Examines the interlaboratory variation of HIV-1 RNA measurement on the plasma of Belgian patients. Prediction of the rate of disease progression; Observation on the antiretrovirus treatment; Use of Amplicor assay in detecting differences of HIV-1 RNA in plasma.