Contribution of serology in congenital toxoplasmosis diagnosis: results from a 10-year French retrospective study.

This study aimed to evaluate different serological strategies for the postnatal diagnosis of congenital toxoplasmosis (CT) and establish a biological algorithm for CT diagnosis. The study analyzed serological data of immunoglobulins M, A, and G (IgM, IgA, IgG) performed by immunoenzymatic and compared immunological profile (CIP) assays in 668 newborns with CT diagnosis across four testing periods: P1 (D0- D10), P2 (D11-D35), P3 (D36-D45), and P4 (>D45). Forty-nine percent of the 668 CT cases were diagnosed during P1 and 34%, 4%, and 12% during P2, P3, and P4, respectively. CIP assays detected neosynthetized IgMs/IgGs in 98% of CT cases diagnosed during P1, while IgMs and IgAs were detected in 90% and 57% of CT cases diagnosed during P2 and in 88% and 67% of diagnoses made during P3, respectively. Detection of neosynthesized IgMs/IgGs, IgMs, and IgAs by immunoassay contributed to CT diagnosis in 81%, 77%, and 60% of cases, respectively. In total, 46% of serum samples were positive for all three parameters, 27% for two, and 27% for one of the three. The study recommends using the CIP assay as standard during P1 for CT diagnosis and IgM and IgA immunoassays after P1. A clinical and biological follow-up in a specialized center with a close collaboration between biologists and clinicians is highly recommended to increase the chances of early diagnosis. Overall, this study provides useful information for the development of a biological algorithm for CT diagnosis, which can aid in early detection and appropriate treatment of this disease.

Prospective study of serum and aqueous humour anti-Hsp70.1 IgG antibody levels in ocular toxoplasmosis.

AIMS: We evaluate whether the serum and aqueous humour (AH) level of IgG anti-Hsp70.1 antibodies improved the biological diagnosis of ocular toxoplasmosis. METHODS AND RESULTS: In this prospective cross-sectional and multicentre study, serum and AH were collected at the time of active uveitis. Anti-Hsp70.1-antibody levels were determined by ELISA. Patients with confirmed (Group A1, n = 21) or suspected ocular toxoplasmosis (group A2, n = 30) were enrolled, as well as a control group of patients with cataract (group B, n = 42). Serum IgG anti-Hsp70.1 antibody levels were not significantly different within the group of uveitis patients (A1, n = 21 vs A2, n = 30, P = .8) and were significantly associated with the affected retinal zone (P = .006) and with the size of the retinal lesion (P = .03). Serum anti-Hsp70.1 antibody level was positive in 10 out of the 18 patients of group A2. Significant anti-Hsp-70.1 antibody level in AH was reported in only three patients (3 eyes) with confirmed ocular toxoplasmosis. CONCLUSION: While the level of IgG anti-Hsp-70.1 antibody in AH did not improve the laboratory diagnosis of ocular toxoplasmosis, its level in serum was of major significance for retinal damage diagnosis.

Performance of a Toxo IgM prototype assay for the diagnosis of maternal and congenital Toxoplasma infections.

Background Testing for anti-Toxoplasma immunoglobulin (Ig)M is of main importance in the context of pregnancy to promptly alert to an acute maternal infection prior to the detection of IgG and to identify infected newborns. Their absence helps exclude a recent maternal infection in the presence of IgG. Methods The performance of a Toxo IgM immunocapture prototype assay (bioMérieux, France) was compared with that of the VIDAS® Toxo IgM and the ARCHITECT® Toxo IgM (Abbott, Germany) assays at Grenoble and Lyon (France). A total of 1446 sera were sampled from (i) 1054 pregnant women found by routine workup to have no infection (n = 843), an acute infection (<4 months) (n = 28) or a chronic infection (>4 months) with residual (n = 120) or no IgM (n = 62); (ii) 50 three-serum panels sampled immediately after a maternal seroconversion; (iii) 242 samples taken in 41 children with a congenital toxoplasmosis (n = 122) and in 40 uninfected children (n = 120). Results In pregnant women, the overall agreement with the VIDAS® assay was 99.23% (CI: 99.16-99.27) and that with the ARCHITECT® assay was 99.14% (CI: 99.07-99.17). Sensitivity of the Toxo IgM prototype assay was 100% (CI: 87.66-100.00) and specificity was 99.64% (98.96-99.93). In acute maternal infections, IgM assays were detected as early with the prototype as with the other two. In the congenitally infected children, IgM were detected on their first sample in 25/40 with the prototype vs. 23/40 with the VIDAS® test. No uninfected child had positive IgM. Conclusion The prototype performed comparably to the ARCHITECT® and VIDAS® Toxo IgM assays for the diagnosis of maternal and congenital toxoplasmosis.

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®.

Title: Performances comparatives des tests ISAGA IgM et ELISA pour le diagnostic des infections maternelles et congénitales à Toxoplasma : quelle technique pourrait remplacer ISAGA IgM ? Abstract: Le test d'immunocapture ISAGA pour la détection des immunoglobulines M anti-Toxoplasma est une technique manuelle connue pour son excellente sensibilité et spécificité. Le but de cette étude rétrospective et multicentrique était de comparer les performances et la concordance entre l'ISAGA et d'autres techniques de détection d'IgM avant l'arrêt de la commercialisation de l'ISAGA. Les performances analytiques des différents tests ont été évaluées à partir de 1 341 échantillons de sérum d'adultes présentant des IgM positives et des IgG négatives à Toxoplasma gondii, et de 1 206 sérums de nouveau-nés nés de mères présentant une séroconversion. La concordance entre les tests a été évaluée sur 13 506 échantillons de sérum d'adultes et 5 795 sérums d'enfants. La sensibilité de Toxo-ISAGA IgM® (adultes 98,7 %, nouveau-nés 63,1 %) était similaire à celle de Platelia Toxo IgM® (adultes 94,4 %, nouveau-nés 64,6 %) et significativement supérieure à celle de Liaison Toxo IgM® (adultes 90,6 %), Architect/Alinity Toxo IgM® (adultes 95,7 %, nouveau-nés 48,6 %) et Vidas Toxo IgM® (adultes 81,8 %, nouveau-nés 17,5 %). Cependant, les spécificités variaient entre 24,4 % (Platelia Toxo IgM®) et 95,2 % (Liaison Toxo IgM®) chez les adultes et étaient >95 % pour tous les tests chez les nouveau-nés. L'analyse des coefficients kappa a montré une meilleure concordance entre ISAGA IgM® et les autres tests chez les enfants (0,75­0,83%) que chez les adultes (0,11­0,53%). Nous concluons qu'en l'absence de Toxo-ISAGA IgM®, l'association d'une technique très sensible (Platelia Toxo IgM® ou Architect/Alinity Toxo IgM®) et d'une technique très spécifique (Vidas Toxo IgM® ou Liaison Toxo IgM®) est recommandée pour la détection des IgM dans les sérums adultes. Pour les nouveau-nés, Platelia Toxo IgM® apparaît comme la meilleure alternative en remplacement de Toxo-ISAGA IgM®.

IgM triplet in neonatal diagnosis by immunoblotting and its potential use as a diagnostic marker for congenital toxoplasmosis.

Primary infection during pregnancy by the protozoan Toxoplasma gondii can be worrisome because transmission to the fetus may lead to congenital toxoplasmosis (CT). Neonatal diagnosis is usually performed by serological profile comparison of the mother and newborn. As previously reported in 2012 by C. L'Ollivier et al., three IgM bands at 75, 90 and 100 kDa called the "IgM triplet" has caught our attention and seems to be pathognomonic of CT. This retrospective multicenter study involved nine reference laboratories included in the French National Reference Center for Toxoplasmosis network and concerned determining the specificity and sensitivity of this IgM triplet. On this basis, we were able to propose a new read of the comparison of IgG and IgM immunoblot profiles of mother and infant to increase the sensitivity of this diagnostic marker. The effect of the trimester of pregnancy at the time of infection, but also of maternal treatment with pyrimethamine/sulfadiazine/folinic acid on the presence of this IgM triplet in the infant, could be studied. The presence of the triplet appears pathognomonic for the diagnosis of CT, and it increased the sensitivity of the immunoblot assay from 55.04% to 72.48%. As a result, it would be wise to enhance conventional immunoblot reading by adding the presence of the three IgM bands in the infant pattern for neonatal diagnosis of CT.

Title: La triplette IgM dans le diagnostic néonatal par immunoblot et son utilisation potentielle comme marqueur diagnostique de la toxoplasmose congénitale. Abstract: La primo-infection pendant la grossesse par le protozoaire Toxoplasma gondii peut se révéler préoccupante car la transmission au fœtus peut conduire à une toxoplasmose congénitale (TC). Un diagnostic néonatal est généralement réalisé par comparaison des profils sérologiques de la mère et du nouveau-né. Comme précédemment rapporté en 2012 par C. L'Ollivier et al., l'association de trois bandes d'IgM à 75, 90, et 100 kDa appelée la « triplette IgM ¼ a retenu notre attention et semble être pathognomonique de la TC. Cette étude rétrospective multicentrique impliquant neuf laboratoires de référence inclus dans le réseau du Centre National de Référence pour la Toxoplasmose a permis de déterminer la spécificité et la sensibilité de cette triplette IgM. Ainsi, cela a permis de proposer une nouvelle lecture de la comparaison des profils d'immunoblot IgG et IgM de la mère et du nourrisson pour augmenter la sensibilité de ce marqueur diagnostique. L'effet du trimestre de la grossesse au moment de l'infection mais aussi du traitement maternel par pyriméthamine/sulfadiazine/acide folinique sur la présence de la triplette IgM chez l'enfant a pu être analysé. La présence de cette triplette semble pathognomonique pour le diagnostic de TC et elle permet d'augmenter la sensibilité du test immunoblot de 55,04 % à 72,48 %. Ainsi, il pourrait être judicieux d'améliorer la lecture conventionnelle de l'immunoblot en ajoutant la présence des trois bandes IgM dans le schéma du nourrisson pour le diagnostic néonatal de TC.

Diagnostic Accuracy of LDBIO-Toxo II IgG and IgM Western Blot in Suspected Seroconversion in Pregnancy: A Multicentre Study.

The high sensitivity of the automated tests used for Toxoplasma gondii serology can yield false-positive IgM results due to aspecific reactions. On the other hand, specific therapy can delay IgG production and, therefore, the diagnosis of seroconversion. There is a need for confirmation tests to early detect seroconversions during pregnancy. We conducted a multicentre study to evaluate the diagnostic accuracy of the Toxo II IgG and a new, not yet commercialised Toxo II IgM western blot (WB) (LDBio diagnostics Lyon France) on 229 sera corresponding to 93 patients with seroconversions and 158 sera corresponding to 68 patients with nonspecific IgM. Sensitivity was 97.8% for IgM WB and 98.9% for IgG WB. Specificity was 89.7% and 100%, respectively. The concordance between IgM and IgG Toxo WB with the final diagnosis was very good, K = 0.89 and K = 0.99, respectively. In 5 cases (5.4%), the appearance of IgM, and in 55 cases (59.1%), the appearance of IgG was recorded by WB earlier than by traditional tests. In 10 cases (10.8%), IgM was detected after the traditional tests and in 2 cases (2.2%) for IgG. The association of IgG and IgM WB on the same sample not only detected all seroconversions but also correctly identified most of the false-positive results.

Serological diagnosis of toxoplasmosis: evaluation of the commercial test recomLine Toxoplasma IgG immunoblot (Mikrogen) based on recombinant antigens.

BACKGROUND: IgG detection to determine immune status to Toxoplasma gondii infection and seroconversion mainly relies on ELISA techniques and, if necessary, on a confirmatory test, Western blot. This study evaluated the performance of the recomLine Toxoplasma IgG immunoblot (IB-recomLine) (Mikrogen) as a confirmatory test on a large number of sera. A total of 171 sera were selected (113 patients) and had previously been analyzed by two ELISA tests, ARCHITECT (Abbott) and VIDAS (bioMérieux) ± LDBIO-Toxo II IgG Western blot (WB-LDBIO) (LDBio). The sera were classified into three groups: group 1 included 50 sera without difficulty in interpreting the IgG results (patients with documented past infection or uninfected); group 2 included 47 sera with difficulty in interpreting the ELISA results; and group 3 included 74 sequential sera from 25 pregnant women with seroconversion. RESULTS: In group 1, overall IgG agreements were 94% and 90% with ARCHITECT and VIDAS, respectively. In group 2, low agreement was observed between IB-recomLine and WB-LDBIO, with eight false-positive and 13 false-negative results. In group 3, 4/13 seroconversions were detected earlier with IB-recomLine compared to other tests. CONCLUSIONS: IB-recomLine allowed for earlier diagnosis of toxoplasmic seroconversion compared to both ELISA tests and WB-LDBIO but led to insufficient performance to confirm the immune status when ELISA results were discordant or equivocal.

Title: Diagnostic sérologique de la toxoplasmose : évaluation du test commercial recomLine Toxoplasma IgG immunoblot (Mikrogen) basé sur des antigènes recombinants. Abstract: Contexte : La détection des IgG pour déterminer le statut immunitaire vis-à-vis de l'infection à Toxoplasma gondii et de la séroconversion repose principalement sur les techniques ELISA et, si nécessaire, sur un test de confirmation, le Western blot. Cette étude a évalué les performances de l'immunoblot recomLine Toxoplasma IgG (IB-recomLine) (Mikrogen) en tant que test de confirmation sur un grand nombre de sérums. Un total de 171 sérums ont été sélectionnés (113 patients) et ont été préalablement analysés par deux tests ELISA, ARCHITECT (Abbott) et VIDAS (bioMérieux) ± LDBIO-Toxo II IgG Western blot (WB-LDBIO) (LDBio). Les sérums ont été classés en trois groupes : le groupe 1 comprenait 50 sérums sans difficulté d'interprétation des résultats IgG (patients avec antécédents d'infection documentée ou non infectés); le groupe 2 comprenait 47 sérums avec des difficultés d'interprétation des résultats ELISA; le groupe 3 comprenait 74 sérums séquentiels de 25 femmes enceintes séroconverties. Résultats : Dans le groupe 1, les concordances globales des IgG étaient respectivement de 94 % et 90 % avec ARCHITECT et VIDAS. Dans le groupe 2, une faible concordance a été observée entre IB-recomLine et WB-LDBIO, avec huit faux positifs et 13 faux négatifs. Dans le groupe 3, 4/13 séroconversions ont été détectées plus tôt avec IB-recomLine par rapport aux autres tests. Conclusions : IB-recomLine a permis un diagnostic plus précoce de la séroconversion toxoplasmique par rapport aux tests ELISA et WB-LDBIO, mais a conduit à des performances insuffisantes pour confirmer le statut immunitaire lorsque les résultats ELISA étaient discordants ou équivoques.

Molecular diagnosis of toxoplasmosis: recent advances and a look to the future.

INTRODUCTION: Toxoplasmosis is a globally distributed parasitic infection that can be particularly severe when opportunistic or congenital. Its diagnosis requires accurate and rapid techniques that rely mainly on serology and molecular methods. AREAS COVERED: The aim of this review was to discuss the positioning of the molecular diagnosis of toxoplasmosis according to the different clinical situations possibly resulting from infection with T. gondii, and to detail recent developments in this technique. The English and French literature were searched with the following keywords: 'Toxoplasmosis', "Molecular diagnosis" and 'PCR'. EXPERT OPINION: Molecular techniques have revolutionized the diagnosis of toxoplasmosis, and practices have considerably evolved over the past decades. However, there is still a high degree of inter-laboratory heterogeneity which impairs comparisons between results and studies. Efforts to standardize practices are underway.

Serology for Toxoplasma in Immunocompromised Patients: Still Useful?

Toxoplasmosis represents one of the most common comorbidity factors in solid organ or hematopoietic stem cell transplant recipients as well as in other immunocompromised patients. In the past decades, availability and performance of molecular tools for the diagnosis or the exclusion of toxoplasmosis in these patients have greatly improved. However, if accurately used, serology remains a complementary and essential diagnostic tool for physicians and medical parasitologists for the prevention and management of toxoplasmosis in immunocompromised patients as well. It is required for determination of the immunological status of patients against Toxoplasma. It also helps diagnose and monitor complex cases of opportunistic Toxoplasma infection in immunocompromised patients. New perspectives are available to further enhance their yield and ease of use.

Multicenter Comparative Assessment of the TIB MolBiol Toxoplasma gondii Detection Kit and Four Laboratory-Developed PCR Assays for Molecular Diagnosis of Toxoplasmosis.

Toxoplasmosis can be a life-threatening infection, particularly during pregnancy and in immunocompromised patients. The biological diagnosis of toxoplasmosis is challenging and has been revolutionized by molecular detection methods. This article summarizes the data of a multicenter study involving four centers to assess the performances of a commercial PCR assay as compared with four in-house PCR assays using Toxoplasma gondii standards, 20 external quality control specimens, and 133 clinical samples. This clinical cohort includes well-characterized clinical samples corresponding to different clinical situations: confirmed congenital toxoplasmosis (44 samples), toxoplasmosis in immunocompromised patients (25 samples), and chorioretinitis (5 samples). Furthermore, 59 samples from patients without toxoplasmosis were included as negative controls. The analytical sensitivities of the five methods tested were very similar; and the limit of Toxoplasma DNA detection was around 0.01 T. gondii genome per reaction for all the methods. The overall concordance between the commercial PCR and the four in-house PCR assays was 97.7% (130/133). The clinical sensitivity and specificity were >98% and could be increased for the commercial kit when PCR was performed in multiplicate to detect low parasitic loads. In conclusion, the commercial PCR assay shows suitable performances to diagnose the different clinical forms of toxoplasmosis.

Chronic toxoplasmosis and sleepiness in obstructive sleep apnea: Is there a link?

INTRODUCTION: Sleepiness is the main clinical expression of obstructive sleep apnea (OSA) syndrome resulting from upper airway collapse. Recent studies have discussed the fact that the presence of T. gondii cysts in the brain and the resulting biochemical and immunological mechanisms could be linked to neurobehavioral disorders. The aim of the present study was to explore the potential impact of chronic toxoplasmosis on sleepiness and on obstructive sleep apnea (OSA) severity in OSA obese patients. MATERIALS AND METHODS: A case control study on obese patients screened for OSA was performed. According to the sleep disorder and matched based on gender, age and body mass index (BMI), two groups of obese patients were selected from our sample collection database. All patients were tested for toxoplasmosis serological status measuring anti-Toxoplasma IgG and IgM levels. Univariable and multivariable logistic regression models were performed to assess the impact of chronic toxoplasmosis on sleepiness and OSA severity. RESULTS: 107 obese patients suffering from OSA were included in the study (median age: 53.3 years Interquartile range (IQR): [41.9-59.9]; median BMI: 39.4 kg/m2 IQR: [35.5-44.1], apnea-hypopnea index = 27.5 events/h [10.7-49.9]). Chronic toxoplasmosis was present in 63.4% and 70.7% of patients with or without sleepiness (p = 0.48), respectively and was not associated either to sleepiness (OR: 0.76, 95% CI: [0.52; 2.33], p = 0.64) or OSA severity (OR = 1.75, 95% CI: [0.51; 5.98] p = 0.37). CONCLUSION: Although chronic Toxoplasma infection in immunocompetent humans has been associated to several behavioral disorders or pathologies in recent literature, we demonstrate here that chronic toxoplasmosis is not associated to sleepiness and to sleep apnea syndrome severity in obese patients suspected of sleep apnea syndrome.

How to estimate time of infection with Toxoplasma gondii in pregnant women. Use of specific IgG and IgM kinetics by 7 techniques on 691 sera.

A difficulty when detecting both anti-Toxoplasma gondii-specific IgG and IgM in pregnant women is estimating the date of infection. The aim of this study was to compare the anti-Toxoplasma-specific immunoglobulin kinetics of 7 serological techniques to date the infection and to draw kinetic curves that are easy to use on a daily basis. IgG and IgM antibodies were measured on 691 sera samples. IgM appeared a few days, less than 1 week, after the beginning of the infection. Then, the levels of IgM reached a peak at approximately 3, 4, and 5 weeks with Toxo-ISAGA® IgM, IgM homemade indirect immunofluorescence assays, and Vidas Toxo® IgM, respectively. Furthermore, the Architect Toxo® IgG titers were higher than those of the Vidas Toxo® IgG results in recent infection (less than 6 months). This study provides new average IgM and IgG curves that can help to determine the approximate date of infection.

Diagnosis of toxoplasmosis after allogeneic stem cell transplantation: results of DNA detection and serological techniques.

BACKGROUND: The biological diagnosis of toxoplasmosis after allogeneic hematopoietic stem cell transplantation (HSCT) is based on the detection of Toxoplasma gondii DNA in blood specimens or other samples. Serological testing is used mainly to define the immunity status of the patient before HSCT. The aim of our study was to examine the performance of polymerase chain reaction (PCR) and serological techniques in the diagnosis of toxoplasmosis after HSCT. METHODS: Seventy patients underwent allogeneic HSCT from September 2004 through September 2006. DNA was detected by PCR, and immunoglobulin G and immunoglobulin M were detected by enzyme-linked immunosorbent assay. RESULTS: The results of immunoglobulin G detection before allogeneic HSCT were positive in 40 (57.1%) of the patients and negative in 30 (42.9%). After HSCT, 57 patients (81.4%) had test results that were negative for immunoglobulin M and had negative results of DNA detection, without toxoplasmosis infection. Four patients (5.7%) had at least 4 samples with positive PCR results and/or test results positive for immunoglobulin M against T. gondii; toxoplasmosis was then confirmed by clinical symptoms. Nine patients (12.9%) with positive PCR results and 1 or 2 samples with test results negative for immunoglobulin M were considered to have asymptomatic T. gondii infection. Reactivation of latent infection was the cause of toxoplasmosis in 3 of the 4 patients, and toxoplasmosis occurred as a primary infection in 1 patient. The detection of specific anti-T. gondii immunoglobulin M was the only biological evidence of toxoplasmosis in 2 patients, and samples were positive for immunoglobulin M before PCR was performed in 1 patient. CONCLUSIONS: Thus, after HSCT, all patients were at risk for toxoplasmosis; all patients who receive HSCTs should be followed up with biological testing that combines PCR and serological techniques.

Serodiagnosis of recently acquired Toxoplasma gondii infection in pregnant women using enzyme-linked immunosorbent assays with a recombinant dense granule GRA6 protein.

Indirect immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays (ELISAs) with a recombinant GRA6 protein of Toxoplasma gondii were developed and evaluated for accurate diagnosis of recently acquired infection in pregnant women. According to the results from Toxoplasma serodiagnostic tests, women were classified into 3 groups representing acute (group I), chronic (group II), or no Toxoplasma infection (group III). To discriminate group I from group II sera, the GRA6-IgG-ELISA reached sensitivity and specificity of 87.5% and 94.1%, respectively. Although 22 (91.7%) of 24 group I sera were positive by the GRA6-IgM-ELISA, only 1 (2.9%) of 34 group II sera scored positive. The GRA6-IgM-ELISA displayed a meaningful correlation with Vidas Toxo IgM and exhibited higher specificity (97.1%) than Euroimmun IgM ELISA (88.2%) (Euroimmun, Lübeck, Germany) for detection of recent infection. These results demonstrate that IgG and IgM ELISA with rGRA6 are useful to identify and discriminate recent from past Toxoplasma infection in pregnant women.

Management of toxoplasmosis in transplant recipients: an update.

INTRODUCTION: Toxoplasmosis is a life-threatening parasitic disease for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. The risk of toxoplasmosis in transplant patients mainly depends on the degree of immunosuppression, the tropism of Toxoplasma gondii for the grafted tissue, and the seroprevalence in the general population. Although transplant recipients with toxoplasmosis have a high mortality rate, there are neither well-defined recommendations nor a consensus for the management of this disease in these patients. Areas covered. This review focuses on the management of toxoplasmosis in transplant recipients and discusses the various strategies for diagnosis, prevention, treatment, and follow-up in clinical practice. The literature search was conducted on publications in English and French using the search terms 'Toxoplasma gondii,' 'organ transplant,' and 'transplant recipients.' Expert commentary. The diagnosis of toxoplasmosis has greatly improved over the last two decades, but it is still a fatal illness. Non-specificity of the symptoms, resulting in a delay before diagnosis, and therapeutic failure are the main causes of death. The development of active treatments against cysts is one of the current challenges that will considerably improve the management of toxoplasmosis in transplant recipients by clearing chronic infection to avoid T. gondii reactivation.

Value of Toxoplasma gondii detection in one hundred thirty-three placentas for the diagnosis of congenital toxoplasmosis.

The placenta examination by polymerase chain reaction and mouse inoculation increased the sensitivity of the diagnosis of congenital toxoplasmosis at birth from 60% (use of serologic techniques on the newborn's blood only) to 75% (both serologic techniques and placental analysis). The specificity of Toxoplasma gondii detection in the placenta was 94.7%.

The dense granule protein GRA2, a new marker for the serodiagnosis of acute Toxoplasma infection: comparison of sera collected in both France and Iran from pregnant women.

GRA2 is a highly immunogenic protein secreted from the dense granules of Toxoplasma gondii. Recent success in purifying full-length, soluble GRA2 from bacteria as a thioredoxin (TRX)-(Hisx6) fusion protein led to investigate the antigenicity of the recombinant protein against human sera. On immunoblots, TRX-(Hisx6)-GRA2 was recognized by sera collected in Iran from T. gondii-infected pregnant women. An IgG enzyme-linked immunosorbent assay was developed to evaluate the reactivity of sera, collected from pregnant women both in France and Iran, to the TRX-(Hisx6)-GRA2 fusion protein. Specificity of the test was 96.4%. Sensitivity of the GRA2 enzyme-linked immunosorbent assay ranged from 95.8% (sera collected in France) to 100% (sera collected in Iran) for sera of acute infection and from 65.7% (sera collected in France) to 71.4% (sera collected in Iran) for sera of chronic infection. The recombinant GRA2 could thus advantageously complement previously described T. gondii antigens for the serodiagnosis of acute Toxoplasma infection.

Late diagnosis of congenital toxoplasmosis based on serological follow-up: A case report.

Toxoplasma gondii is a protozoan parasite infecting up to one third of the world's population. T. gondii infection is usually benign in immunocompetent patients but can be life-threatening when congenitally transmitted. Congenital toxoplasmosis presentation ranges from severe central nervous system and ocular features, to a well appearing newborn with onset of complications late in childhood. The diagnosis of subclinical form remains important since early treatment reduces later complications such as chorioretinitis. We report an atypical case of congenital toxoplasmosis with a delayed diagnosis, based on Toxoplasma-specific serological follow-up. The infant was born to a mother who became infected during pregnancy, thus inducing infant biological and clinical follow-up. Neither biological nor clinical arguments favored a diagnosis of congenital toxoplasmosis until ten months of life. Congenital toxoplasmosis was then suspected because of an unusual increase of specific IgG levels. Diagnosis was confirmed by detection of newly synthesized newborn Ig isotypes using complementary comparative mother-to-child immunological profile techniques and specific treatment therefore administered. This report highlights the importance to follow up newborns at risk of congenital toxoplasmosis with specific and newborn-appropriate techniques until Toxoplasma-IgG titers are completely negative. This allows not only the exclusion of congenital toxoplasmosis when serology becomes negative, but also the diagnosis and treatment of congenital toxoplasmosis when infection is detected later in development.