Diagnostic Relevance of Immunoglobulin G Avidity for Hepatitis A Virus

Roque–Afonso, Anne–Marie; Grangeot-Keros, L.; Roquebert, Bénédicte; Desbois, Delphine; Poveda, Jean-Dominique; Mackiewicz, Vincent; Dussaix, Élisabeth

doi:10.1128/jcm.42.11.5121-5124.2004

Cited by 30 publications

(21 citation statements)

References 16 publications

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“…All IgM-positive samples in the present study were positive for HAV RNA, which provided information on the specificity of surveillance data and the absence of false-positive serologic results. However, the false-positive serologic results may occur as described previously for patients with persisting HAV IgM [34], cross-reactions in the test (e.g., in acute-phase infections with Epstein-Barr virus) [35], or nonspecific polyclonal activation of memory cells [36]. HAV RNA was detected in 31 IgM-positive patients.…”

Section: Discussionmentioning

confidence: 88%

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

et al. 2012

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The aim of the present study was to investigate the seroprevalence of Hepatitis A virus antibodies in patients with clinical symptoms of viral hepatitis and molecular characterization of the detected isolates. The present study deals with the seroprevalence and the genetic diversity of HAV in 400 Tunisian patients presenting in dispensaries (160 patients) and in University Hospitals (240 patients) with hepatitis symptoms between 2006 and 2008. The patients with acute hepatitis were mainly from rural regions. However, the total number of patients was decreased over time. The collected samples were from patients with hepatitis symptoms occurring mainly during January-March (36.7, 26, and 35.5%) and SeptemberDecember (39.4, 43.4,and 35.5%) during the three years of study, respectively. However, HAV infection was established for only 110 among 400 patients. The detected isolates were clustered within sub-genotype IA. The present study constituted another report of the continued surveillance of HAV infection in the region of Monastir and the molecular characterisation of the detected strains.

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Section: Discussionmentioning

confidence: 88%

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

et al. 2012

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“…Avidity tests have been developed for rubella virus (17), Toxoplasma gondii (5,8,18), cytomegalovirus (CMV) (1), varicella-zoster virus (11), human immunodeficiency virus (25), hepatitis viruses (22,26,27,29), Epstein-Barr virus (28), and others. For immunocompetent, untreated individuals, the presence of low-avidity IgG directed against pathogens may indicate a recent infection, whereas the presence of high-avidity IgG excludes a primary infection (13,14).…”

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confidence: 99%

Development of Fully Automated Determination of Marker-Specific Immunoglobulin G (IgG) Avidity Based on the Avidity Competition Assay Format: Application for Abbott Architect Cytomegalovirus and Toxo IgG Avidity Assays

et al. 2009

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Determination of the avidity of immunoglobulin G (IgG) directed against a specific marker has become an established diagnostic tool for identifying or excluding acute infections with pathogens. A novel assay format termed AVIcomp (avidity competition based on mass action) circumventing the conventional chaotropic format has been developed for determination of the avidity of marker-specific IgG in patient specimens. Its applications for cytomegalovirus (CMV) and Toxoplasma gondii are presented. Specific high-avidity IgG from the patient specimen is selectively blocked using a soluble antigen in a sample pretreatment reagent, and the amount of remaining specific low-avidity IgG is determined relative to that in an untreated control. The comparison of the conventional chaotropic format, represented by the Radim CMV IgG Avidity assay, and the newly developed AVIcomp method, as exemplified by the Architect CMV IgG Avidity assay, on blood drawn within 4 months after seroconversion revealed a sensitivity of 100% (97.3% by an alternative calculation) for the AVIcomp format versus 87.5% (75.7% by an alternative calculation) for the chaotropic avidity assay. The specificity on 312 CMV IgG reactive and CMV IgM nonreactive specimens from pregnant women was 100% for the AVIcomp assay and 99.7% for the conventional avidity assay. The Architect Toxo IgG Avidity assay showed an agreement of 97.2% with the bioMérieux Vidas Toxo IgG Avidity Assay employing chaotropic reagents. These performance data suggest that the AVIcomp format shows superior sensitivity and equivalent specificity for the determination of IgG avidity to assays based on the chaotropic method and that the AVIcomp format may also be applicable to other disease states.Over recent years, numerous publications have shown that the avidity of marker-specific immunoglobulin G (IgG) is a suitable tool for distinguishing between acute and recurrent or past infection with a pathogen (7). Avidity tests have been developed for rubella virus (17), Toxoplasma gondii (5,8,18), cytomegalovirus (CMV) (1), varicella-zoster virus (11), human immunodeficiency virus (25), hepatitis viruses (22,26,27,29), Epstein-Barr virus (28), and others. For immunocompetent, untreated individuals, the presence of low-avidity IgG directed against pathogens may indicate a recent infection, whereas the presence of high-avidity IgG excludes a primary infection (13,14). During the early immune response, IgG antibodies are targeting a multiplicity of different epitopes of the pathogen with relatively low avidity. Clonal selection finally results in high-avidity antibodies directed mainly against a limited number of immunodominant epitopes (5).For T. gondii infections, high-avidity IgG serves to rule out a recent infection as well; however, low-avidity results are not indicative of a recent or past infection (16). This is due to the fact that the antibody avidity maturation kinetics for T. gondii

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“…Pour répondre à ce problème diagnostique, le Centre national de référence (CNR) du VHA (laboratoire de microbiologie de l'hôpital Paul-Brousse, Villejuif) a mis au point un test de mesure de l'avidité des IgG anti-VHA [41]. Nombre d'infections virales ou de maladies auto-immunes peuvent présenter une symptomatologie hépatique devant laquelle la recherche d'IgM anti-VHA est justifiée.…”

Section: Avidité Des Igg Anti-vhaunclassified