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

Abstract

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...

Epidemiology of and Diagnostic Strategies for Toxoplasmosis

“…4). Specific IgE antibodies are also produced early and rapidly disappear (126). Levels of specific IgM antibodies usually decrease after 1 to 6 months; they become negative in 25% of patients within less than 7 months (155) but commonly remain detectable for a year or longer.…”

A comparative study of congenital toxoplasmosis between public and private hospitals from Uberlândia, MG, Brazil

“…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 (Foudrinier et al 2003).…”

Evaluation of the Liaison Automated Testing System for Diagnosis of Congenital Toxoplasmosis

“…At least at the end of the first year, the diagnosis has to be determined. Little is known about serologic profiles of infants obtained by different testing systems (7,21,24,25). The aim of the study was to compare the Liaison toxoplasmaspecific assays with the DT and ISAGA-IgM.…”