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.

Interpretation of very low avidity indices acquired with the Liaison XL Toxo IgG avidity assay in dating toxoplasmosis infection.

Congenital toxoplasmosis is an important cause of complications in pregnancy. Toxoplasmosis is often asymptomatic and thus serological tests are usually performed to screen for it. A first serum which exhibit both IgG and IgM may be due to nascent toxoplasmosis seroconversion, non-specific IgM reaction, or residual IgM. The IgG avidity test has been proposed to identify latent infections. A high index excludes recent toxoplasmosis whereas an intermediate or low index only suggests a recent infection, the caveats being that some people with latent Toxoplasma gondii infection show IgG with low or intermediate avidity. In this study, we investigated the ability of the Liaison XL Toxo IgG avidity (DiaSorin, Saluggia, Italy) assay to confirm recent infection when IgG avidity index is very low (≤ 0.1). Four thousand two hundred ninety-seven sera exhibiting both IgG and IgM were included and avidity was performed on the Liaison device according to the manufacturer's recommendations. One hundred twenty-six sera on the 297 sera which exhibited very low IgG avidity indices (≤ 0.1) could be exploited: 97% of sera with IgG avidity indices < 0.05 actually corresponded to recent infection (less than 3 months). A similar but less pronounced trend was observed for the sera exhibiting indices between 0.05 and 0.1 (69% corresponded to recent infections). The IgG avidity index data we obtained with the Liaison XL Toxo device are similar to those obtained with other devices. This body of consistent results underlines the interest of very low IgG avidity indices as a sign of probable recent toxoplasmosis.

[Serological monitoring and prevention of toxoplasmosis during pregnancy]. / Surveillance sérologique et prévention de la toxoplasmose chez la femme enceinte.

Serological monitoring and prevention of toxoplasmosis during pregnancy. Determination of the serological status against toxoplasmosis is mandatory in France during pregnancy. Recently, the national social welfare system decided to include new exams (IgG avidity and western-blot) useful to assess the serological status and to date the infection with a better accuracy. The role of the attending doctor is essential, particularly at the beginning of pregnancy and after delivery. We summarize here key points which must be known by a general practitioner to understand serological results and take care of his patients.

Surveillance sérologique et prévention de la toxoplasmose chez la femme enceinte. Le dépistage systématique de la toxoplasmose chez la femme enceinte est une obligation légale en France. Le code de nomenclature des actes de biologie médicale a intégré en 2019 de nouveaux examens (western-blot IgG et mesure de l'indice d'avidité des IgG) permettant d'établir le statut sérologique ou de dater l'infection avec une meilleure spécificité. La place du médecin traitant est essentielle dans la prise en charge de la grossesse, en particulier au moment de la déclaration et pour le suivi post-partum. Nous rappelons ici les éléments biologiques essentiels que tout praticien doit connaître et les éléments de la prise en charge à organiser en fonction des résultats sérologiques.

Comparative evaluation of 11 commercialized rapid diagnostic tests for detecting Trypanosoma cruzi antibodies in serum banks in areas of endemicity and nonendemicity.

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity.

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®.

Larva Currens: Report of Seven Cases and Literature Review.

Strongyloidiasis is a frequent and often unrecognized parasitic disease because of the frequently asymptomatic nature and lack of sensitivity of diagnostic tests. Under conditions of immunosuppression (particularly systemic corticosteroid treatment), potentially fatal dissemination may occur. Thus, prevention and early diagnosis are important. Larva currens is a rare and pathognomonic cutaneous sign of strongyloidiasis, but is poorly described because of its unpredictable and fleeting occurrence. We report seven imported cases of larva currens seen in Paris between 1990 and 2020. We illustrate the clinical and biological features of this specific but uncommon sign of strongyloidiasis with clinical pictures. There were three males and four females, aged between 29 and 58 years. There were five migrants from endemic countries, one tourist and one expatriate. Digestive disorders were the main extracutaneous signs. All patients had eosinophilia above 0.5 G/L. All cases were confirmed by stool tests. All were cured with ivermectin. The rapidity and the short duration of the creeping eruption distinguish it from other parasitoses. Ivermectin is a treatment of choice. The key point is to think about preventing disseminated strongyloidiasis before giving corticosteroids not only among migrants but also among expatriates and tourists in endemic countries.

Ocular Toxocariasis in Adult Caucasian Patients: Clinical Presentations and Treatment Outcomes.

PURPOSE: To report the clinical features and treatment outcomes in adult Caucasians with ocular toxocariasis (OT) and investigate their prognosis depending on their serological status. METHODS: Retrospective observational cohort study (2016-2021) including consecutive adults with uveitis and positive western blot (WB) in the aqueous humor or vitreous. The presence of serum antibodies was not necessary for inclusion, allowing to compare the outcomes depending on the serological status. RESULTS: Seventeen eyes of 15 patients were included. Mean age at diagnosis was 51.9 years. Vitreous inflammation was the most frequent sign (100%). Vitreoretinal tractions (41.2%) and chorioretinal granulomas (58.8%) were less prevalent. Atypical features were: spontaneous intravitreal hemorrhage (23.5%), exudative retinal detachment (11.8%), isolated macular edema (17.6%), papillitis (29.4%) and vasculitis (47.1%). Twenty percent of patients had a positive serum serology. Baseline clinical features did not differ statistically depending on the serological status; however, the degree of inflammation was numerically higher in patients with negative serology. Overall, macular thickness, anterior and posterior segment inflammation improved significantly after treatment with oral albendazole, systemic ± local corticosteroids. Vitrectomy (47.1%) was performed in case of persistent vitritis (62.5%), retinal detachment (12.5%) and intravitreous hemorrhage (25%). CONCLUSION: OT has no pathognomonic sign and atypical presentations were not infrequent in this adult Caucasian cohort. Serum antibodies were rarely positive, stressing on the importance of ocular sample analysis, especially in case of atypical features. Serum antibodies may prove useful in forecasting the rapidity of inflammation clearance. Antiparasitic and anti-inflammatory treatment was safe and efficient in most cases.

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.

Assessment of Droplet Digital PCR for the Detection and Absolute Quantification of Toxoplasma gondii: A Comparative Retrospective Study.

Accurate tools for Toxoplasma gondii detection and quantification can be valuable for the early and effective management of toxoplasmosis. Droplet digital PCR (ddPCR) is a next-generation end-point PCR technique with high performance. The objective of the study was to evaluate the performance of ddPCR for the detection and absolute quantification of T. gondii. From January 2019 to October 2020, DNA samples collected at the Laboratory of Parasitology and Mycology of Pitié-Salpêtrière Hospital in Paris were retrospectively analyzed by ddPCR and real-time quantitative PCR (qPCR). To detect T. gondii with the best sensitivity possible, the REP-529 multicopy target was used. For absolute quantification of T. gondii, a specific single-copy target of α-tubulin was designed. T. gondii detection by ddPCR and qPCR was strongly correlated (R2 = 0.93), with a total concordance of 96.7% (n = 145/150). Quantification of T. gondii using ddPCR was successful for 15 of 35 samples showing a parasite load ≥170 copies/mL of DNA eluate using the α-tubulin target. The qPCR REP-529 quantification based on a standard curve was approximate and dependent on the strain genotype, which led to an estimate of parasite copy number 14- to 160-fold superior to the ddPCR result. In total, ddPCR is an effective molecular method for T. gondii detection that shows equivalent performance to qPCR. For robust T. gondii quantification, ddPCR is clearly more accurate than semiquantitative qPCR methods.

Chronic schistosomiasis imported in France: A retrospective multicentre analysis of 532 patients, calling for international recommendations.

BACKGROUND: Schistosomiasis is a major public health issue for migrants. This study aims to describe the clinical presentation and management of imported schistosomiasis in France. METHODS: We included all new cases of schistosomiasis in patients aged ≥18 years, defined by a positive specific Western blot and/or a positive parasitological analysis of urine, stool or biopsy, between January 1, 2016, and December 31, 2019, in 4 laboratories in Paris and Western France. RESULTS: Over the study period, 532 patients were included. Mean age was 37 years (18-91), and 461/532 (87 %) were men. Among 476/532 (89 %) patients born in an endemic area, 433 (91 %) were born in sub-Saharan Africa. Most of the patients (405/532, 76 %) had only a positive serology, and 127/532 (24 %) had ova on microscopic examination. Among 361/532 (68 %) who had at least one urine, stool or biopsy analysis, microscopic analysis was positive in 127 (35 %). Imaging showed lesions compatible with schistosomiasis in 88/164 (54 %) patients with clinical symptoms and 13/29 (45 %) patients without (p = 0.5). Patients who arrived in France less than one year before diagnosis were more likely to have clinical symptoms than those who arrived in France 1-5 years and >5 years prior to diagnosis (52 %, 41 % and 43 %, respectively, p = 0.03). Two-hundred and seventeen patients (40.8 %) were left untreated. CONCLUSION: Approximately 50 % of patients with imported chronic schistosomiasis have radiological abnormalities, whether they are symptomatic or not, and management is heterogeneous. Multidisciplinary international guidelines are requested to clarify the management of this neglected disease.

French guidelines for the etiological workup of eosinophilia and the management of hypereosinophilic syndromes.

Eosinophilic-related clinical manifestations are protean and the underlying conditions underpinning eosinophilia are highly diverse. The etiological workup of unexplained eosinophilia/hypereosinophilia can be challenging, and can lead sometimes to extensive, inappropriate, costly and/or invasive investigations. To date, guidelines for the etiological workup and management of eosinophilia are mainly issued by hematologists, and thus mostly cover the scope of clonal hypereosinophilic syndromes (HES). Here, thanks to an extensive literature review, and thanks to the joint work of a large panel of experts involving physicians from both adult and pediatric medicine and from various subspecialties (as well as a representative of a patients' association representative), we provide recommendations for both the step-by step diagnostic workup of eosinophilia (whether unexplained or within specific contexts) as well as the management and follow-up of the full spectrum of eosinophilic disorders (including clonal, reactive, lymphocytic and idiopathic HES, as well as single-organ diseases). Didactic prescription summaries intended to facilitate the prescription of eosinophil-targeted drugs are also provided, as are practical diagnostic and therapeutic algorithms. Lastly, this set of recommendations also includes a summary intended for general practitioners, as well as an overview of the therapeutic patient education program set up by the French reference center for HES. Further updates will be mandatory as new validated information emerges.

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.

Toxoplasmosis in patients with an autoimmune disease and immunosuppressive agents: A multicenter study and literature review.

BACKGROUND: Cases of Toxoplasma reactivation or more severe primary infection have been reported in patients receiving immunosuppressive (IS) treatment for autoimmune diseases (AID). The purpose of this study was to describe features of toxoplasmosis occurring in patients with AID treated by IS therapy, excluded HIV-positive and transplant patients. METHODS: A multicenter descriptive study was conducted using data from the French National Reference Center for Toxoplasmosis (NRCT) that received DNA extracts or strains isolated from patients, associated with clinical data. Other cases were retrieved through a questionnaire sent to all French parasitology and internal medicine departments. Furthermore, a systematic literature review was conducted. RESULTS: 61 cases were collected: 25 retrieved by the NRCT and by a call for observations and 36 from a literature review. Half of the cases were attributed to reactivation (50.9%), and most of cases (49.2%) were cerebral toxoplasmosis. The most common associated AID were rheumatoid arthritis (28%) and most frequent treatments were antimetabolites (44.3%). Corticosteroids were involved in 60.7% of cases. Patients had a favorable outcome (50.8%) but nine did not survive. For 12 cases, a successful Toxoplasma strain characterization suggested the possible role of this parasitic factor in ocular cases. CONCLUSION: Although this remains a rare condition, clinicians should be aware for the management of patients and for the choice of IS treatment.

Human neurocysticercosis: comparison of different diagnostic tests using cerebrospinal fluid.

Neurocysticercosis (NC), caused by the larval stage of Taenia solium, is one of the most common parasitic diseases of the central nervous system. The diagnosis of NC is mostly based on costly brain neuroimaging (computed tomography and/or nuclear magnetic resonance), which is rarely accessible in most affected areas. The most sensitive and specific tools for NC diagnosis are imagery techniques. The identification of specific antibodies and antigens is currently used only to support NC diagnosis due to their limited specificity and sensitivity. This study was performed to compare immunodiagnostic assays (antibody detection by enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunoelectrotransfer blotting [EITB] and HP10 antigen detection by ELISA) with the detection of parasite DNA by PCR amplification of a repetitive element of the parasite genome in the cerebrospinal fluid (CSF) of 121 radiologically and clinically characterized NC patients. Patients were divided into six groups according to the stage of the parasites and their localization. The CSF cellularity of each patient was also recorded. When all patients were considered, PCR exhibited the highest sensitivity (95.9%) and variable specificity (80% or 100%) depending on the controls used. The sensitivities of antibody detection by ELISA and EITB were not significantly different, and ELISA identified HP10 antigen mostly when vesicular cysticerci were located in the subarachnoideal basal cisterns. These results can help in the selection of different individual assays or combinations of assays to be used in NC diagnosis according to different requirements.

Evaluation of the Chagas Western Blot IgG Assay for the Diagnosis of Chagas Disease.

Chagas disease is a debilitating and often fatal pathology resulting from infection by the protozoan parasite Trypanosoma cruzi. In its recommendations, the World Health Organization states that the diagnosis of T. cruzi infection is usually based on the detection of antibodies against T. cruzi antigens and performed with two methodologically different assays. An inconclusive result can be resolved with a third "confirmatory" assay. The objective of this article is to evaluate the effectiveness of the Chagas Western Blot IgG assay (LDBio Diagnostics, Lyon, France) as a confirmatory serologic test. The Chagas Western Blot IgG assay was performed with native antigens derived from a T. cruzi strain of the TcVI genotype. Retrospective sera were provided by two parasitology laboratories (France and Argentina). The sensitivity, specificity, positive predictive value and negative predictive value of the Chagas blot were all 100% in our sera collection. The Chagas blot is an easy and qualitative method for the diagnosis of Chagas disease, with results in less than 2 h. This immunoblot has potential as a supplemental test for the confirmation of the presence of antibodies against T. cruzi in serum specimens. Nonetheless, the very good initial results presented here will need to be confirmed in larger studies.

Imported schistosomiasis in Paris region of France: A multicenter study of prevalence and diagnostic methods.

BACKGROUND: There are few data on imported schistosomiasis - especially in children. The objectives of the present study were to estimate the prevalence of imported schistosomiasis in at-risk children in the greater Paris region of France and to compare diagnostic methods. METHOD: Children at risk of schistosomiasis who consulted or were hospitalized in four hospitals in the greater Paris region were prospectively included. Clinical and laboratory data were collected. Urine and feces samples were screened for Schistosoma spp. using microscopy, a point-of-care circulating cathodic antigen and a real-time polymerase chain reaction assay. Serum samples were screened using Western blot, ELISA, indirect hemagglutination, and immunochromatographic assays. The diagnosis was characterized as confirmed (positive microscopy analysis) and as suspected (positive ELISA and Western blot assays). The prevalence of schistosomiasis and the tests' performances were estimated using the latent class method. RESULTS: A total of 114 children were included. Most of the children were newly arrived migrants from sub-Saharan Africa. The mean age was 13.2 years-old. There were 12 (10.5%) confirmed cases and 13 (11.4%) suspected cases. Half of the confirmed and suspected cases were asymptomatic. The prevalence was 24.3%. The ELISA and the Western blot assays presented the same sensitivity (83%) and specificity (99%). The serum immunochromatographic assay also showed good performance. CONCLUSIONS: The high prevalence of imported schistosomiasis among at-risk children in the greater Paris region confirms the need for systematic screening. A serum immunochromatographic assay appears to be one of the most effective screening methods for a low cost.

Pooling aqueous humor samples: bias in 2D-LC-MS/MS strategy?

The proteomic analysis of body fluids presents a major challenge in studies of human diseases. Traditional techniques for protein separation require large volumes and large amounts of protein, which may be difficult to obtain for certain fluids, such as the aqueous humor (AH). Two-dimensional liquid chromatography (2D-LC-MS/MS), adapted for peptides separation from complex protein mixtures, provides an alternative approach in proteomic analysis with a potential utility in biomarker research. We investigated several different 2D-LC-MS/MS methods for use with the AH of patients with cataract, traditionally used as a control group in studies of ocular diseases. We compared analyses of individual samples with analyses of pools of proteins or peptides, and found that the investigation strategy used strongly influenced protein identification. We identified 71 proteins related to extracellular proteins highly abundant in serum (e.g., albumin or transferrin) and involved in various functions, such as transport and metabolism, together with intracellular (myeloblastin) or organelle-specific proteins (cytochrome c). An evaluation of the advantages and disadvantages of each method suggested that individual analyses and the use of peptide mixtures should be favored as complementary techniques in the search for biomarkers in ocular diseases.

Testing blood donors for Chagas disease in the Paris area, France: first results after 18 months of screening.

BACKGROUND: Chagas disease is endemic in Latin America (LA). Currently 10 million people are infected despite World Health Organization efforts aimed at preventing domestic transmission. However, with the migration of infected asymptomatic individuals to nonendemic countries, transmission of Chagas disease by transfusion may become a worldwide problem. The observation that the number of cases of Chagas disease has increased over the past 10 years in French Guiana, together with the results of a previous hospital-based study in the Paris area, confirms the transmission of Chagas disease from patients coming from LA. For these reasons, the French authorities stopped the collection of blood in French Guiana in 2005 and began screening blood donors in the French Caribbean islands and, in 2007, in continental France. STUDY DESIGN AND METHODS: Data on birth place, mother's birth place, and travel in LA were recorded for at-risk donors. These subjects were tested using two enzyme-linked immunosorbent assays (ELISAs). RESULTS: Of the 312,458 individuals who gave blood in the Paris area during an 18-month period, 30,837 were tested. Of these, 972 were born in LA, three of whom were positive for the two ELISAs and immunofluorescence tests. The prevalence of Trypanosoma cruzi-positive donors was 9.7 in 100,000 tested donors, but 0.31% among donors born in LA. Serology tests gave discrepant results in 1.02% of the samples. CONCLUSION: The efficiency of blood donor screening programs could be improved by screening only blood donors who were born in LA or who have traveled in LA for extended periods, using a single enzyme immunoassay.