Diagnosis of Congenital Toxoplasmosis: Performance of Four IgG and IgM Automated Assays at Birth in a Tricentric Evaluation

Could PLATELIA Toxo IgM be the new gold standard for the serological diagnosis of congenital toxoplasmosis: a French multicenter study

To assess the performance of PLATELIA Toxo IgM (Bio-Rad) and Toxo ISAGA (BioMérieux) to detect anti-Toxoplasma IgM in infants at risk of congenital toxoplasmosis, a retrospective multicenter study was conducted comparing serological results obtained in the framework of routine diagnosis work-up for congenital toxoplasmosis. All infants born to mothers infected with T. gondii during pregnancy from 2010 to 2020 with at least 6 months of serological follow-up were included (n = 1,010). One thousand ten cases were included, of which 250 infants (24.75%) had congenital toxoplasmosis. A total of 1039 sera were included. The concordance between the two techniques was 96%, with kappa coefficient of 0.87, showing an almost perfect agreement between ISAGA and PLATELIA. Cumulative sensitivity and specificity were 73.2% and 99.5.% and 74.8% and 100% for ISAGA and PLATELIA, respectively. The mean time to detect IgM using ISAGA and PLATELIA tests was 6.9 ± 20.1 days and 5.6 ± 14.7 days, respectively not significant (ns). Finally, the sensitivity of ISAGA and PLATELIA to detect IgM antibodies in infected neonates at 5 days of life was 62% and 64%, respectively. Performances of PLATELIA Toxo IgM assay were comparable to the gold standard ISAGA. This enzyme-linked immunosorbent assay is suitable for routine serology for the diagnosis of congenital toxoplasmosis in newborns. IMPORTANCE This study will help clinical microbiologists to chose an alternative serological method for the neonatal diagnosis of congenital toxoplasmosis, once the gold standard technique ISAGA will be withdrawn next year.

Comparative performance of ISAGA IgM and ELISA assays for the diagnosis of maternal and congenital Toxoplasma infections: which technique could replace ISAGA IgM?

The ISAGA immunocapture test for the detection of anti-Toxoplasma immunoglobulin M is a manual technique known for its excellent sensitivity and specificity. The purpose of this retrospective, multicenter study was to compare the performances and agreement between ISAGA and other IgM detection techniques before cessation of ISAGA production. The analytic performance of the different tests was evaluated using 1,341 serum samples from adults with positive IgM and negative IgG to Toxoplasma gondii, and 1,206 sera from neonates born to mothers with seroconversion. The agreement between the tests was evaluated on 13,506 adult and 5,795 child serum samples. The sensitivity of Toxo-ISAGA IgM® (adults 98.7%, neonates 63.1%) was similar to that of Platelia Toxo IgM® (adults 94.4%, neonates 64.6%), and significantly higher than Liaison Toxo IgM® (adults 90.6%), Architect/Alinity Toxo IgM® (adults 95.7%, neonates 48.6%), and Vidas Toxo IgM® (adults 81.8%, neonates 17.5%). However, the specificities varied between 24.4% (Platelia Toxo IgM®) and 95.2% (Liaison Toxo IgM®) in adults and were >95% for all tests in neonates. An analysis of the kappa coefficients showed better agreement between ISAGA IgM® and the other tests in children (0.75-0.83%) than in adults (0.11-0.53%). We conclude that, in the absence of Toxo-ISAGA IgM®, the association of a very sensitive technique (Platelia Toxo IgM® or Architect/Alinity Toxo IgM®) and a very specific technique (Vidas Toxo IgM® or Liaison Toxo IgM®) is recommended for IgM detection in adult sera. For neonates, Platelia Toxo IgM® appeared to be the best alternative to replace Toxo-ISAGA IgM®.

A retrospective study of air quality associated with teratogenic pathogen screening in women of reproductive age in southern China

Adverse pregnancy outcomes are associated with a poor ambient atmospheric environment. Infections by teratogenic pathogens such as cytomegalovirus (CMV) and herpes simplex virus (HSV) are the main cause of the worse pregnant outcomes. However, environmental factors governing these infections are uncertain and epidemiological studies are limited. An epidemiological study on relationships between air pollutants and antibodies against teratogenic pathogens will be explored. In total, 5475 women of childbearing age were enrolled in the study between January 2018 and December 2019 in a hospital in Shantou, China. Antibodies against pathogens were measured by electrochemical luminescence. Everyday air quality data, concerning particulate matter (PM), sulfur dioxide (SO2), nitrogen dioxide (NO2), and other parameters, were acquired from a government web site, and the relationships between them were evaluated with nonparametric and multivariate linear regression analyses. Not only titers of herpes simplex virus HSV(I+II) IgGs in spring, but also titers of cytomegalovirus IgG (CMV IgG) and HSV I IgG in autumn, both had positive associations with concentrations of SO2. When PM2.5 or PM10 exposure is elevated, HSV(I+II) IgGs, TOX IgM should be paid more attention in spring or summer. Air pollution may be crucial for teratogenic pathogen infections. This study highlights air pollution could increase the risk of teratogenic pathogen infection, implying stronger measures should be taken to protect air environment and screenings of associated antibody should be strengthened in different season.

Advances and Challenges in Diagnostics of Toxoplasmosis in HIV-Infected Patients

Toxoplasma gondii is a worldwide distributed protozoan parasite. This apicomplexan parasite infects one-third of the population worldwide, causing toxoplasmosis, considered one of the neglected parasitic infections. In healthy humans, most infections are asymptomatic. However, in immunocompromised patients, the course of the disease can be life-threatening. Human immunodeficiency virus (HIV)-infected patients have a very high burden of Toxoplasma gondii co-infection. Thus, it is essential to use modern, sensitive, and specific methods to properly monitor the course of toxoplasmosis in immunodeficient patients.

Diagnosis of Congenital Toxoplasmosis: No Benefit of IgA Antibody Detection by Platelia ELISA in a Tricentric Evaluation

The diagnostic accuracy of a commercial Toxoplasma gondii IgA antibody enzyme-linked immunosorbent assay (ELISA) was evaluated in the context of routine practice on 289 newborns with congenital toxoplasmosis (CT) and 220 healthy controls. The performance of this assay was compared to that of the current gold-standard test for anti- Toxoplasma IgM detection, an immunosorbent agglutination assay (ISAGA).