Duration of specific immunoglobulin a antibody following acute toxoplasmosis as determined by enzyme immunoassay and immunosorbent agglutination assay

Francis, Janet; Joynson, D. H. M.

doi:10.1007/bf01970965

Cited by 35 publications

(23 citation statements)

References 5 publications

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“…It may be concluded that detection of T. gondii -specific IgG and IgM may provide the basis for diagnosis of recent exposure or acute infection, but during critical periods, such as pregnancy, the presence of antibodies in a single sample does not provide a reliable estimate of the time of infection [30,31] . However, the combination of IgM, IgG and IgG avidity provides a tool that can assist in the determination of when an infection occurred, even with one sample [13,[32][33][34][35][36] .…”

Section: Igm and Igg Avidity Testing In Pregnancy 41 Toxoplasmosismentioning

confidence: 98%

Clinical utility of avidity assays

Hazell¹

2007

Expert Opinion on Medical Diagnostics

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IgM may persist for months, presenting a risk of an erroneous diagnosis where serology is the only available tool. Indeed, IgM may be detected in secondary infection as a result of crossreactivity and/or nonspecific stimulation of the immune system. One test that can aid the serologist is IgG avidity testing, in that the avidity of IgG is low early in infection with the avidity of IgG antibodies increasing over time. Congenital toxoplasmosis can induce serious sequelae. Detectable IgM usually persists long after the acute infection. IgG avidity can be an important aid in diagnosis and assessing the risk to the fetus. Another infection that is of concern in pregnancy is cytomegalovirus (CMV). In pregnant women it is very important to differentiate primary from secondary infection, as primary infection presents the highest risk to the fetus. Serologic detection of IgM alone is not a specific marker of primary CMV infection. IgG avidity can have utility in identifying or excluding primary CMV infections during pregnancy. Outside of pregnancy, IgG avidity testing is increasingly recognized as a valuable tool. During the recent West Nile virus (WNV) epidemic in the US, it was recognized that WNV-specific IgM may persist for 6 - 12 months following exposure. Thus, a person presenting to their clinician with nonspecific symptoms may be tested and return a positive WNV IgM that may be the product of exposure during the previous period. In this environment, WNV IgG avidity testing is able to provide some assistance. IgG avidity testing should not be used alone and without an understanding of the limitations of the technique. Serology remains an important tool for the diagnosis and management of infectious disease. Classically, IgM is defined as a marker of acute infection and IgG, in the absence of clinical disease, is often considered a marker of past infection. However, the clinical reality can be quite different.

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Section: Igm and Igg Avidity Testing In Pregnancy 41 Toxoplasmosismentioning

confidence: 98%

Clinical utility of avidity assays

Hazell¹

2007

Expert Opinion on Medical Diagnostics

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“…Diagnosis of acute infection depends on detection of Toxoplasma-specific immunoglobulin G (IgG) and IgM antibodies (1, 24) but does not make it possible to estimate the time of infection with accuracy (12,17). Measurement of specific IgG avidity has been shown to be the best tool, in combination with IgM analysis, for determining when the infection took place (14,16,18,19,21,23,25).…”

mentioning

confidence: 99%

Use of an Immunoglobulin G Avidity Assay Based on Recombinant Antigens for Diagnosis of PrimaryToxoplasma gondiiInfection during Pregnancy

Beghetto¹,

Buffolano²,

Spadoni³

et al. 2003

J Clin Microbiol

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The objective of this work was to develop an antibody-specific immunoglobulin G (IgG) avidity assay to discriminate between acute and latent phases of Toxoplasma gondii infection by using recombinant antigens. One hundred twenty-one serum samples from women who developed IgG antibodies against Toxoplasma during pregnancy were used. The IgG avidities of antibodies directed against epitopes carried by fragments of GRA3, GRA7, MIC3, and SAG1 antigens were measured by performing parallel enzyme immunoassays. The avidity index for Toxoplasma-specific antibodies against a homogeneous mixture of recombinant GRA3, GRA7, MIC3, and SAG1 antigens correlated closely with the IgG avidity of antibodies against lysed whole-cell T. gondii antigen. The avidity assay performed with the recombinant MIC3 antigen highlighted the presence of avidity low-antibodies IgG exclusively in sera collected within 2 months after primary infection. The presence of T. gondii-specific, low-avidity IgG antibodies against recombinant MIC3 antigen can be used to determine the point of infection with T. gondii within a 2-month time frame after infection.

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“…Conversely, the IgM assay can be negative in patients with secondary reactivation or congenital toxoplasmosis (3,6). Although anti-Toxoplasma IgA antibodies are also informative (i.e., no natural IgA), they can persist for Ͼ6 months after infection, making it difficult to determine the precise date of infection in pregnant women (8,9). There is therefore growing interest in the use of IgE in this setting (1,10,14,18,22).…”

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confidence: 99%

Clinical Value of Specific Immunoglobulin E Detection by Enzyme-Linked Immunosorbent Assay in Cases of Acquired and Congenital Toxoplasmosis

et al. 2003

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The clinical value of immunoenzymatic (enzyme-linked immunosorbent assay) detection of anti-Toxoplasma immunoglobulin E (IgE) was assessed by studying 2,036 sera from 792 subjects, comprising seronegative controls and subjects with acute, active, reactivated, or congenital toxoplasmosis. Included were nonimmunized adults; pregnant women with recently acquired infection (acute toxoplasmosis); immunocompetent subjects with recently acquired severe infection (active toxoplasmosis) expressed as fever, adenopathies, splenomegaly, pneumonia, meningitis, or disseminated infection; subjects-some of them immunocompromised-whose previously moderate IgG antibody levels rose, suggesting a reactivation of quiescent toxoplasmosis; and infants born to seroconverted mothers and evaluated for diagnosis of congenital infection and therapeutic management. Specific IgE antibodies were never detected in seronegative subjects. They were present in 85.7% of asymptomatic seroconverters and in 100% of seroconverters with overt toxoplasmosis, following two different kinetics: in the former, the specific IgE titer generally presented a brief peak 2 to 3 months postinfection and then fell rapidly, whereas specific IgE persisted at a very high titer for several months in the latter. IgE emerged concomitantly with the increase in IgG during toxoplasmic reactivation. For neonatal diagnosis of congenital toxoplasmosis, IgE was less informative than IgM and IgA (sensitivities, 59.5, 64.3, and 76.2%, respectively) and had a specificity of 91.9%. Nevertheless, simultaneous measurement of the three isotypes at birth improved the diagnostic yield to 81% relative to the combination of IgA and IgM. Emergence of specific IgE during postnatal treatment for congenital toxoplasmosis is a sign of poor adherence or inadequate dosing.Toxoplasmosis, a cosmopolitan protozoan disease, is often asymptomatic in humans. Its diagnosis is mainly based on serological tests. Classically, serodiagnosis includes titration of specific immunoglobulin G (IgG) (showing past exposure) and screening for specific IgM, which is suggestive of recent exposure or ongoing active infection (17). However, IgM antibody detection can be due to naturally interfering IgM (15) or to the persistence of IgM for a long time after primary infection. Conversely, the IgM assay can be negative in patients with secondary reactivation or congenital toxoplasmosis (3, 6). Although anti-Toxoplasma IgA antibodies are also informative (i.e., no natural IgA), they can persist for Ͼ6 months after infection, making it difficult to determine the precise date of infection in pregnant women (8, 9). There is therefore growing interest in the use of IgE in this setting (1,10,14,18,22). Given the major role of Toxoplasma gondii P30 membrane protein in early antibody synthesis (4), we have used an enzyme-linked immunosorbent assay (ELISA) based on a monoclonal anti-P30 antibody to screen for specific IgE.The aim of this study was to determine the kinetics of antiToxoplasma IgE in ELISA and the clinical value of...

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Duration of specific immunoglobulin a antibody following acute toxoplasmosis as determined by enzyme immunoassay and immunosorbent agglutination assay

Cited by 35 publications

References 5 publications

Clinical utility of avidity assays

Clinical utility of avidity assays

Use of an Immunoglobulin G Avidity Assay Based on Recombinant Antigens for Diagnosis of PrimaryToxoplasma gondiiInfection during Pregnancy

Clinical Value of Specific Immunoglobulin E Detection by Enzyme-Linked Immunosorbent Assay in Cases of Acquired and Congenital Toxoplasmosis

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