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3. Correction of under-quantified specimens with the second version of the Roche COBAS(R) AmpliPrep(R)/COBAS(R) TaqMan(R) assay for HIV-1 viral load

Author

Annelies De Bel, Marissens, D., Debaisieux, L., Liesnard, C., Sigismond Van Den Wijngaert, Sabine Lauwers, DEnis Piérard, Immunology and Microbiology, and Microbiology and Infection Control

Subjects
RT-PCR, HIV, Viral load
Abstract

Initial evaluations of the COBAS(R) AmpliPrep/COBAS(R) TaqMan(R) HIV-1 Test (CAP/CTM) showed good performance but afterwards reports about under-quantification became available. The aim of this study was to investigate if the problem is solved with the second version of this assay, the COBAS(R) AmpliPrep/COBAS(R) TaqMan(R) HIV-1 Test, version 2.0 (CAP/CTM v2.0). Remaining plasma of 375 consecutive HIV-1 positive samples with viral load >/=4000 copies/ml was collected in 3 labs. Samples were diluted and retested with our routine method COBAS(R) AmpliPrep/COBAS(R) AMPLICOR(R) HIV-1 MONITOR Test v1.5 in the ultrasensitive mode (CAP/CA PHS) as well as with CAP/CTM and CAP/CTM v2.0 tests. An absolute difference between the results of two methods of >/=0.71 log10 copies/ml (cp/ml) was defined as moderately discrepant and an absolute difference of >/=0.93 log10 cp/ml as severely discrepant. In addition, criteria for considering the new methods equivalent to the routine method were formulated. CAP/CTM compared to CAP/CA PHS: 36 (9.5%) and 20 (5.3%) samples were respectively considered as moderately and severely under-quantified by CAP/CTM. The mean difference between CAP/CTM and CAP/CA PHS was -0.32 log10 cp/ml. Eight out of 19 of the severely under-quantified samples were from patients infected with HIV-1 subtype B strain. CAP/CTM v2.0 compared to CAP/CA PHS: No sample was moderately or severely under-quantified by CAP/CTM v2.0. A mean difference of +0.08 log10 cp/ml was found with CAP/CTM v2.0 compared to CAP/CA PHS. The under-quantification problem of the CAP/CTM kit was clearly demonstrated. Criteria for equivalence of CAP/CTM v2.0 to the routine test CAP/CA PHS were fulfilled.

Published
2010

4. Is the Underquantification Issue Solved with the Second Version of the Cobas Ampli/Prep/Cobas TaqMan HIV-1 Viral Load Assay?

Author

De Bel, Annelies, Marissens, D., Debaisieux, L., Liesnard, C., Van Den Wijngaert, Sigismond, Piérard, Denis, Lauwers, Sabine, and Immunology and Microbiology

Subjects
Roche COBAS, HIV-1, Viral load
Abstract

Background: The HIV-1 viral load (VL) assay is a major tool in the follow-up of HIV-infected individuals. Classical end-point amplification techniques for VL are more and more replaced by real-time technologies. Initial evaluations of the Cobas Ampliprep/Cobas Taqman (CAP/CTM) v1.0 assay were good but afterwards reports about serious underquantification became available. The aim of this study was to investigate if the underquantification problem is solved with the second version of this CAP/CTM assay. Materials & Methods: 381 consecutive HIV-1 positive samples with VL ?4000 copies/ml with Cobas Amplicor were collected in 3 labs. Only one sample per patient was included. The left over material after routine testing of the original specimen was diluted 1:5 or 1:10, aliquoted and tested in parallel with Cobas Ampliprep/Cobas Amplicor (CAP/CA) v1.5, CAP/CTM v1.0 and v2.0. An absolute difference between the results of two methods of more than 0.7 log copies/ml was defined as moderately discrepant and an absolute difference of more than 0.9 log copies/ml was defined as severely discrepant. Criteria to be fulfilled for considering the new methods equivalent to the routine method were as follows: an absolute difference between CAP/CA and respectively CAP/CTM v1.0 and v2.0 of less than 0.7 log c/ml for at least 95% and less than 0.9 log c/ml for at least 99% of all samples. Mean values (log copies/ml) were compared with the t-test for paired data. Results: One sample appeared severely overquantitated with both Taqman assays (+1.29 and +1.84 log copies/ml with v1.0 and v2.0 respectively). This is probably due to a primer mismatch and underquantification with the CAP/CA assay. The patient's CD4 count and clinical presentation correlate better with the higher VL. This result was considered as an outlier and was not taken into account in our calculations. CAP/CTM v1.0 compared to CAP/CA: 36 (9.5%) samples were moderately and 20 (5.3%) samples were severely underquantitated. 2 (0.5%) samples were moderately overquantitated. The overall mean difference between CAP/CTM v1.0 and CAP/CA was -0.32 log copies/ml. This difference is statistically significant. Although this difference is less than 0.5 log copies/ml, accepted as clinically relevant, it clearly illustrates the underquantification problem. Moreover, the number of moderately and severely underquantitated samples is unacceptable. CAP/CTM v2.0 compared to CAP/CA: No samples were moderately or severely underquantitated. 8 (2.1%) samples were moderately and 3 (0.8%) were severely overquantitated. A mean difference of +0.07 log copies/ml was found with the CAP/CTM v2.0 compared to CAP/CA. This difference is statistically but not clinically significant. Conclusions: The criteria to consider the new method equivalent to the routine method are fulfilled only for CAP/CTM v2.0. In this evaluation the underquantification problem with the first version of the CAP/CTM kit was clearly demonstrated and it seems to be solved with the second version of this kit.

Published
2009

7. Blinded, multicenter quality control study for the quantification of human immunodeficiency virus type 1 RNA in plasma by the Belgian AIDS reference laboratories

Author

Muyldermans, G., Debaisieux, L., Fransen, K., Marissens, D., Miller, K., Vaira, D., Vandamme, A.m., Verhofstede, A.th., Schuurman, R., Zissis, G., Lauwers, Sabine, Faculty of Sciences and Bioengineering Sciences, and Immunology and Microbiology

Subjects
Aids Reference Laboratories
Abstract

OBJECTIVE: In order to evaluate the interlaboratory variation of HIV-1 RNA measurements in plasma, the Belgian AIDS reference laboratories organized a blinded multicenter quality control study. METHODS: Atest panel of coded spiked HIV-1 plasma samples reflecting the dynamic range of the assay was composed and distributed. The HIV-1 RNA concentration of these samples was determined by the eight Belgian AIDS reference laboratories by means of the Amplicor HIV-1 Monitor version 1.5 assay. RESULTS: Analysis of the results demonstrated that there was little interlaboratory variation for the high concentration range (4.0-5.7 log10 copies/mL), never exceeding 0.2 log10 copies/mL. However the standard deviation for the low concentration range (2.6-3.9 log10 copies/mL) reached up to 0.22 log10 copies/mL. CONCLUSIONS: Since interlaboratory variability never reached 0.5 log10 copies/mL and each of the laboratories was able to detect four-fold differences in plasma HIV-1 RNA levels, the Amplicor assay can be used in multicenter studies without a centralized analysis of samples. Furthermore, this well-characterized proficiency panel of spiked plasma samples could be used as a standard in the study of interassay comparisons. PMID: 11168110 [PubMed - indexed for MEDLINE] Related ArticlesPerformance characteristics of the QUANTIPLEX HIV-1 RNA 3.0 assay for detection and quantitation of human immunodeficiency virus type 1 RNA in plasma. [J Clin Microbiol. 2000] Ultrasensitive reverse transcription-PCR assay for quantitation of human immunodeficiency virus type 1 RNA in plasma. [J Clin Microbiol. 1998] Comparison of NucliSens and Amplicor monitor assays for quantification of human immunodeficiency virus type 1 (HIV-1) RNA in plasma of persons with HIV-1 subtype A infection in Abidjan, Côte d'Ivoire. [J Clin Microbiol. 1998] ReviewThe significance of HIV viral load assay precision: a review of the package insert specifications of two commercial kits. [J Int Assoc Physicians AIDS Care (Chic Ill). 2002] ReviewHuman immunodeficiency virus type 1 reference materials. [Arch Pathol Lab Med. 1990] » See Reviews... | » See All...

Published
2000

9. Prevalence of Genotypic Resistance among Antiretroviral Drug-Naive HIV-1-Infected Patients in Belgium

Author

Van Vaerenbergh, K, primary, Debaisieux, L, additional, De Cabooter, N, additional, Declercq, C, additional, Desmet, K, additional, Fransen, K, additional, Maes, B, additional, Marissens, D, additional, Miller, K, additional, Muyldermans, G, additional, Sprecher, S, additional, Stuyver, L, additional, Vaira, D, additional, Verhofstede, C, additional, Zissis, G, additional, Van Ranst, M, additional, De Clercq, E, additional, Desmyter, J, additional, and Vandamme, A-M, additional

Published
2001
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10. Predictive value of anti-HCV reactivity and ALT level

Author

UCL - (MGD) Centre de transfusion sanguine, Zissis, G., Marissens, D., Herremans, S., De Bruyère, Marc, Lissenko, D., Bohy, E., Luyasu, V., UCL - (MGD) Centre de transfusion sanguine, Zissis, G., Marissens, D., Herremans, S., De Bruyère, Marc, Lissenko, D., Bohy, E., and Luyasu, V.

Published
1994

13. Standardisation of primers and an algorithm for HIV-1 diagnostic PCR evaluated in patients harbouring strains of diverse geographical origin

Author

Vandamme, A.-M., primary, Fransen, K., additional, Debaisieux, L., additional, Marissens, D., additional, Sprecher, S., additional, Vaira, D., additional, Vandenbroucke, A.T., additional, Verhofstede, C., additional, Van Dooren, S., additional, Goubau, P., additional, Desmyter, J., additional, De Beenhouwer, H., additional, van der Groen, G., additional, Piot, P., additional, Liesnard, C., additional, Serruys-Schoutens, E., additional, Pierard, D., additional, Lauwers, S., additional, Zissis, G., additional, Miller, K., additional, Clerc, J.Cogniaux-Le, additional, Sondag-Thull, D., additional, Burtonboy, G., additional, Delferriere, N., additional, Van Emmelo, J., additional, Reniers, S., additional, and Plum, J., additional

Published
1995
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15. Effectiveness of antiretroviral therapy initiated before the age of 2 months in infants vertically infected with human immunodeficiency virus type 1.

Author

Hainaut, Marc, Peltier, Cécile Alexandra, Gérard, Michèle, Marissens, Denise, Zissis, Georges, Levy, Jack, Hainaut, M, Peltier, C A, Gérard, M, Marissens, D, Zissis, G, and Levy, J

Subjects
RETROVIRUS disease treatment, HIV infections, THERAPEUTICS, INFANT disease treatment, REVERSE transcriptase, CHEMICAL inhibitors
Abstract

Unlabelled: The effectiveness and tolerance of antiretroviral therapy with a combination of three reverse transcriptase inhibitors starting at the time of diagnosis (before 2 months of age) was evaluated in four infants with vertically acquired HIV-1 infection. Plasma HIV-1 RNA levels ranged from 230,000 to 1,000,000 copies/ml before onset of triple therapy and fell below 50 copies/ml at 12 to 33 weeks of life in three of the infants. These three children, currently aged 158, 105 and 72 weeks, are asymptomatic, have normal lymphocyte subsets and no hypergammaglobulinaemia. Two children experienced a profound reduction in the amount of proviral DNA detected in blood and have become HIV-1 seronegative, although one of them has had HIV-1 RNA detectable on a single occasion at 114 weeks of life (303 copies/ml). Transient interruption of therapy resulted in a rapid but reversible increase in HIV-1 RNA levels in the third child and was associated with the production of HIV-specific antibodies. The fourth child whose parents were not compliant to treatment and follow-up had a poor virological response.Conclusion: Early treatment of vertically acquired human immunodeficiency virus type 1 infection with three reverse transcriptase inhibitors is well tolerated and can result in such suppression of viral replication that specific antibodies are not produced, that proviral DNA falls to the lower limit of quantitation in blood and that all clinical and immunological manifestations of infection are avoided. Parental adhesion is crucial to the effectiveness of therapy. [ABSTRACT FROM AUTHOR]

Published
2000
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17. Monoclonal antibodies directed against different antigenic determinants of rotavirus

Author

Lambert, J P, Marbehant, P, Marissens, D, and Zissis, G

Abstract

We have developed a series of monoclonal antibodies against the calf strain RIT 4237 (subgroup 1) and the human strain 82-561 (subgroup 3) of rotavirus, both grown in tissue culture, and also against the human rotavirus 81-2162 (subgroup 2), extracted from a fecal specimen. A variety of different specificities was observed among these antibodies, namely, antibodies against group and subgroup determinants, as well as neutralizing antibodies. By using monoclonal antibodies against the subgroup antigen in an enzyme-linked immunoassay system, the constant predominance of subgroup 2 viruses in humans was confirmed in 74 stools collected from children in Brussels who suffered a diarrheal illness between July 1981 and June 1983. The availability of these antibodies also made it possible to improve the sensitivity and the specificity of the test system.

Published
1984
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18. Belgian consensus on therapy and monitoring of adult patients with HIV infection,Consensus belge de therapeutique et de surveillance du patient adulte infecte par le VIH

Author

Cogan, E., Farber, C. M., Liesnard, C., Vooren, J. P., Saint-Pierre, C. H. U., Clumeck, N., Wit, S., Gerard, M., Marc Hainaut, Hermans, Ph, Kabeya, K., Levy, J., Marissens, D., Mundere, J., O Doherty, E., Payen, M. C., Laethem, Y., Zissis, G., Brugmann, C. H. U., Guillaume, M. P., Charleroi, C. H. U., Legrand, J. C., Etterbeek- Ixelles, C. H., Kains, J. P., Moliere-Longchamp, C. H., Coppens, L., and Sprecher, S.

20. Comparative evaluation of NASBA HIV-1 RNA QT, AMPLICOR-HIV monitor; and QUANTIPLEX HIV RNA assay, three methods for quantification of human immunodeficiency virus type 1 RNA in plasma

Author

Revets, H., Marissens, D., Dewit, S., Lacor, P., Clumeck, N., Lauwers, S., and Zissis, G.

Subjects
HIV infection -- Diagnosis, RNA -- Measurement
Abstract

According to the authors' abstract of an article published in Journal of Clinical Microbiology, "Three commercial assays for quantifying plasma human immunodeficiency virus type 1 (HIV-1) RNA were evaluated. The [...]

Published
1996

22. Current levels of drug resistance among therapy-naive HIV-infected patients have significant impact on treatment response.

Author

Derdelinckx I, Van Laethem K, Maes B, Schrooten Y, De Wit S, Florence E, Fransen K, Ribas SG, Marissens D, Moutschen M, Vaira D, Zissis G, Van Ranst M, Van Wijngaerden E, and Vandamme AM

Subjects
Anti-HIV Agents pharmacology, Female, HIV Infections virology, HIV-1 genetics, Humans, Male, Mutation, Reverse Transcriptase Inhibitors pharmacology, Treatment Outcome, Anti-HIV Agents therapeutic use, Drug Resistance, Viral genetics, HIV Infections drug therapy, HIV Infections epidemiology, HIV-1 drug effects, Reverse Transcriptase Inhibitors therapeutic use
Published
2004
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23. Presence of HIV-1 in follicular fluids, flushes and cumulus oophorus cells of HIV-1-seropositive women during assisted-reproduction technology.

Author

Bertrand E, Zissis G, Marissens D, Gérard M, Rozenberg S, Barlow P, and Delvigne A

Subjects
Adult, DNA analysis, Female, HIV Infections transmission, Humans, Infectious Disease Transmission, Vertical, Pregnancy, Pregnancy Complications, Infectious, Sperm Injections, Intracytoplasmic, Viral Load, Fertilization in Vitro, Follicular Fluid virology, HIV Infections virology, HIV-1 genetics, Oocytes virology, RNA analysis
Published
2004
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24. Age-related immune reconstitution during highly active antiretroviral therapy in human immunodeficiency virus type 1-infected children.

Author

Hainaut M, Ducarme M, Schandene L, Peltier CA, Marissens D, Zissis G, Mascart F, and Levy J

Subjects
Adolescent, Age Factors, Antigens, CD19 drug effects, CD4-CD8 Ratio, CD4-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes drug effects, Candida albicans chemistry, Candida albicans immunology, Female, HIV Antibodies analysis, Humans, Infant, Leukocyte Common Antigens drug effects, Male, Mitogens immunology, Protein Tyrosine Phosphatase, Non-Receptor Type 1, Receptors, Antigen, T-Cell immunology, Tetanus Toxoid immunology, Time Factors, Antiretroviral Therapy, Highly Active, HIV Infections drug therapy, HIV Infections immunology, HIV-1 immunology, HIV-1 isolation & purification
Abstract

Objectives: To evaluate the immune reconstitution in HIV-1-infected children in whom highly active antiretroviral therapy (HAART) controlled viral replication and to assess the existence of a relation between the magnitude of this restoration and age., Methods: All HIV-1-infected children in whom a new HAART decreased plasma viral load below 400 copies/ml after 3 months of therapy were prospectively enrolled in a study of their immune reconstitution. Viral load, lymphocyte phenotyping, determination of CD4+ and CD8+ T cell receptor repertoires and proliferative responses to mitogens and recall antigens were assessed every 3 months during 1 year., Results: Nineteen children were evaluated. Naive and memory CD4+ percentages were already significantly increased after 3 months of HAART. In contrast to memory CD4+ percentages, naive CD4+ percentages continued to rise until 12 months. Age at baseline was inversely correlated with the magnitude of the rise in naive CD4+ cells after 3, 6 and 9 months of therapy but not after 12 months. Although memory and activated CD8+ cells were already decreasing after 3 months, abnormalities of the CD8 T cell receptor repertoire and activation of CD8+ cells persisted at 1 year. HAART increased the response to mitogens as early as 3 months after starting therapy., Conclusions: In children the recovery of naive CD4+ cells occurs more rapidly if treatment is started at a younger age, but after 1 year of viral replication control, patients of all ages have achieved the same level of restoration. Markers of chronic activation in CD8+ cells persist after 1 year of HAART.

Published
2003
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25. Prevalence of neutralizing antibodies against a candidate rotavirus vaccine in adults.

Author

Zissis G, Marissens D, Lambert JP, and Marbehant P

Subjects
Adult, Belgium, Child, Enzyme-Linked Immunosorbent Assay, Evaluation Studies as Topic, Humans, Neutralization Tests, Rotavirus pathogenicity, Rotavirus Infections epidemiology, Sex Factors, Viral Vaccines immunology, Antibodies, Viral analysis, Rotavirus immunology, Viral Vaccines administration & dosage
Abstract

Because of the morbidity and mortality from infection with rotaviruses in children under 2 years, in many parts of the world but especially in developing countries, an urgent need for a vaccine has been recognized. At present, a vaccine candidate of bovine origin, the RIT 4237 strain vaccine developed from a strain received from Mebus et al., is available. This strain has been shown to induce cross protection by challenge of colostrum deprived piglets with human rotavirus strains. Before testing its protective effect in children, preliminary studies in adult volunteers are required to evaluate its degree attenuation and immunogenicity. With regard to the latter we have studied the antibody profile of 87 healthy adults, ages 25 to 40 years, from whom blood samples were taken between January and June 1982. Antibodies versus RIT 4237 were measured both by neutralization and ELISA techniques. Analysis of the results revealed a significant difference in antibody levels according to sex, since high neutralizing antibody titers (greater than 1:320) were observed about 7 times more frequently in women than in men. Furthermore, no seasonal variation in the level and the distribution of serum antibody titers was found when comparing blood specimens taken from male volunteers in winter and spring. As far as antibody levels obtained by neutralization and ELISA assays is concerned, a good correlations was noted in 75% of cases. However, in 22 out of 87 sera high levels of neutralizing antibodies were found in association with low ELISA antibody titers or vice versa. These results suggest that screening of adult volunteers should be performed by means of a neutralization assay prior to administration of a candidate vaccine. However, in the absence of such preliminary testing, male volunteers should be chosen since there is a higher probability of low pre-existing antibody levels among such subjects.

Published
1983

26. Prevalence of subgroup 1, 2, and 3 rotaviruses in Belgian children suffering from acute diarrhea (1978-1981).

Author

Lambert JP, Marissens D, Marbehant P, and Zissis G

Subjects
Acute Disease, Belgium, Child, Child, Preschool, Complement Fixation Tests, Diarrhea etiology, Enzyme-Linked Immunosorbent Assay, Gastroenteritis etiology, Humans, Rotavirus Infections complications, Diarrhea microbiology, Gastroenteritis microbiology, Rotavirus classification, Rotavirus Infections microbiology
Abstract

The relative prevalence of human rotavirus subgroups was studied during a 3-year period (1978-1981) by means of a sensitive complement fixation technique. Among 93 rotavirus isolates from children with acute gastroenteritis in Brussels, the prevalence of subgroups 1, 2, and 3 was, respectively 24, 17, and 32%. The remaining 27% of strains could not be typed, but no evidence for the existence of any new subgroup was found. The proportion of strains belonging to the different subgroups remained roughly constant during the study period, showing the simultaneous occurrence of the various subgroups of viruses, even during the annual winter peak of rotavirus gastroenteritis.

Published
1983
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