Clinical severity and molecular characteristics of circulating and emerging rotaviruses in young children attending hospital emergency departments in France

Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in young children worldwide. A prospective surveillance network has been set up to investigate the virological and clinical features of RVA infections and to detect the emergence of potentially epidemic strains in France. From 2009 to 2014, RVA-positive stool samples were collected from 4800 children <5 years old attending the paediatric emergency units of 16 large hospitals. Rotaviruses were then genotyped by RT-PCR with regard to their outer capsid proteins VP4 and VP7. Genotyping of 4708 RVA showed that G1P[8] strains (62.2%) were predominant. The incidence of G9P[8] (11.5%), G3P[8] (10.4%) and G2P[4] (6.6%) strains varied considerably, whereas G4P[8] (2.7%) strains were circulating mostly locally. Of note, G12P[8] (1.6%) strains emerged during the seasons 2011-12 and 2012-13 with 4.1% and 3.0% prevalence, respectively. Overall, 40 possible zoonotic reassortants, such as G6 (33.3%) and G8 (15.4%) strains, were detected, and were mostly associated with P[6] (67.5%). Analysis of clinical records of 624 hospitalized children and severity scores from 282 of them showed no difference in clinical manifestations or severity in relation to the genotype. The relative stability of RVA genotypes currently co-circulating and the large predominance of P[8] type strains may ensure vaccine effectiveness in France. The surveillance will continue to monitor the emergence of new reassortants that might not respond to current vaccines, all the more so as all genotypes can cause severe infections in infants.

A novel immunoassay using recombinant allergens simplifies peanut allergy diagnosis

BACKGROUND

Double-blind placebo-controlled food challenge (DBPCFC) is currently considered the gold standard for peanut allergy diagnosis. However, this procedure that requires the hospitalization of patients, mostly children, in specialized centers for oral exposure to allergens may cause severe reactions requiring emergency measures. Thus, a simpler and safer diagnosis procedure is needed. The aim of this study was to evaluate the diagnostic performance of a new set of in vitro blood tests for peanut allergy.

METHODS

The levels of IgE directed towards peanut extract and recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7, and Ara h 8 were measured in 3 groups of patients enrolled at 2 independent centers: patients with proven peanut allergy (n=166); pollen-sensitized subjects without peanut allergy (n=61), and control subjects without allergic disease (n=10).

RESULTS

Seventy-nine percent of the pollen-sensitized patients showed IgE binding to peanut, despite their tolerance to peanut. In contrast, combining the results of specific IgE to peanut extract and to recombinant Ara h 2 and Ara h 6 yielded a peanut allergy diagnosis with a 98% sensitivity and an 85% specificity at a positivity threshold of 0.10 kU/l. Use of a threshold of 0.23 kU/l for recombinant Ara h 2 increased specificity (96%) at the cost of sensitivity (93%).

CONCLUSION

A simple blood test can be used to diagnose peanut allergy with a high level of precision. However, DBPCFC will remain useful for the few cases where immunological and clinical observations yield conflicting results.

In French children, primary gastritis is more frequent than Helicobacter pylori gastritis

The aim of this study was to analyze the histological characteristics according to the updated Sydney classification (intensity of gastritis, degree of activity, gastric atrophy, intestinal metaplasia, and Helicobacter pylori) in symptomatic children referred for upper gastrointestinal endoscopy. A 4-year retrospective descriptive study was carried out in 619 children (282 females and 337 males), median age 3.75 years (15 days to 17.3 years) referred for endoscopy. Six gastric biopsies were done (three antrum and three corpus) for histological analysis (n = 4), direct examination and H. pylori culture (n = 2). H. pylori status was considered positive if at least two out of three tests were positive and negative if all three tests were negative. The results showed that only 66 children (10.66%) were H. pylori positive. Histological antral and corpus gastritis was detected in, respectively, 53.95% and 59.12% of all cases, most of them of mild grade 1. Antral and corpus activity was grade 1 in 18.57% and 20.03% of cases. H. pylori-positive versus H. pylori-negative children did differ in terms of moderate and marked histological gastritis and grade 2 or 3 activities. One girl had moderate gastric atrophy and another one moderate intestinal metaplasia, both being H. pylori negative. The findings indicate that primary antrum and corpus gastritis is 5.3 and 6.9 times, respectively, more frequent than H. pylori gastritis in French children, with usually mild histological gastritis and activity. Gastric atrophy and intestinal metaplasia are rare.

[Incidence and risk factors of HCV infection in a cohort of intravenous drug users in the North and East of France]

BACKGROUND

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among intravenous drug users we conducted a prospective cohort study of HCV and HIV negative IVDU in the North and East of France.

METHODS

Two hundred and thirty-one IVDU who had injected drug at least once in their lifetime and were negative for anti-HCV and anti-HIV were followed-up every three months over a 12-month period. Serum anti-HCV and anti-HIV antibodies were tested at inclusion in the study and at the end of the follow-up. Data on injection practices and behaviours were collected at inclusion and at each visit, and a test for anti-HCV antibodies was performed on a saliva sample. When this proved positive, an ELISA test for serum anti-HCV antibodies was carried out.

RESULTS

Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9% (95% CI: 4.6-13.4) person-years for HCV infection. Among IVDU who injected at least once during the last 6 months HCV infection incidence was 11% (95% CI: 4.7-17.1) person-years. The multivariate analysis carried out on the inclusion data found female sex alone to be an independent predictive factor of HCV seroconversion. In a Cox proportional hazard multivariate analysis that took into account time-dependent exposures and covariates, we found that syringe and cotton sharing were, after adjusting for other covariates, the only independent predictive factors of HCV seroconversion: hazard ratio: 6.3 [corrected] (95% CI: 1.1-35.4; [corrected] p<0.05) and 16.4 (95% CI: 1.4-190.6; [corrected] p<0.05), respectively.

CONCLUSION

The transmission of the HCV virus persists among French IVDU despite an ongoing national harm reduction program. Injecting material and cotton sharing are the two major determinants of transmission in this cohort.

Fast-electron transport and heating of solid targets in high-intensity laser interactions measured by K alpha fluorescence

We present experimental results on fast-electron energy deposition into solid targets in ultrahigh intensity laser-matter interaction. X-ray K alpha emission spectroscopy with absolute photon counting served to diagnose fast-electron propagation in multilayered targets. Target heating was measured from ionization-shifted K alpha emission. Data show a 200 microm fast-electron range in solid Al. The relative intensities of spectrally shifted Al K alpha lines imply a mean temperature of a few tens of eV up to a 100 microm depth. Experimental results suggest refluxing of the electron beam at target rear side. They were compared with the predictions of both a collisional Monte Carlo and a collisional-electromagnetic, particle-fluid transport code. The validity of the code modeling of heating in such highly transient conditions is discussed.

Incidence and risk factors of HCV and HIV infections in a cohort of intravenous drug users in the North and East of France

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among injecting drug users (IDUs), we conducted a prospective cohort study of HCV- and human immunodeficiency virus (HIV)-negative IDUs in the North and East of France. A total of 231 HCV and HIV IDUs who had injected drugs at least once in their lifetime were followed up every 3 months over a 12-month period. Serum anti-HCV and anti-HIV were tested at inclusion in the study and at the end of the follow-up. Data on injecting practices were collected at inclusion and at each visit. Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9/100 person-years (95% CI 4.6-13.4) for HCV infection. In a multivariable analysis, we found that syringe and cotton sharing were the only independent predictive factors of HCV seroconversion.

[Primary infected aneurysm of the infra-renal aorta:in situ or extra-anatomic bypass?]

There is no agreement in the literature as regards the best treatment for primary infected aneurysms. There is agreement concerning in situ treatment, inlay graft for supra-renal aneurysms. For infra-renal localizations no consensus has been reached. Most Authors prefer biological grafts over prosthetic materials for infected grafts or primary infected aneurysms. We report here a case of primary infected aneurysm treated in two stages. An initial axillo-bifemoral bypass was followed one Month later by aneurysmectomy and wide debridement of infected tIssue. Results were good at two years.

[Rapid identification of pneumococcal antigenes in urines by the Now Streptococcus pneumoniae Binax test]

Streptococcus pneumoniae is responsible for many infectious conditions but probably with an underestimated incidence especially because of the fragility of the bacteria. The present study has evaluated a new test which detects a pneumococcal antigen in urine (Now S.p Binax). Urine samples from 181 children and 40 adults have been tested. All the patients presented with typical clinical signs of pneumococcal infection. Sensitivity = 91.7 %; specificity = 54.2 %; positive predictive value = 50 %; and negative predictive value = 92.9 % have been observed. Although the sensitivity and specificity were lower than those announced by the manufacturer, the test is easy to handle and provides a rapid argument for the diagnosis of pneumococcal infection, especially in the case of invasive infections like meningitis and bacteraemia.

Strategy for diagnosis of congenital toxoplasmosis: evaluation of methods comparing mothers and newborns and standard methods for postnatal detection of immunoglobulin G, M, and A antibodies

In a study involving 14 laboratories supported by the European Community Biomed 2 program, we evaluated immunologic methods for the postnatal diagnosis of congenital toxoplasmosis (CT). Among babies born to mothers who seroconverted to positivity for toxoplasmosis during pregnancy, we analyzed 55 babies with CT on the basis of persistent anti-Toxoplasma immunoglobulin G (IgG) at 1 year of life and 50 control babies without anti-Toxoplasma IgG at 1 year of life in the absence of curative treatment with pyrimethamine-sulfonamides. We tested in-house methods such as the enzyme-linked immunofiltration assay (ELIFA) or Immunoblotting (IB) for the detection of IgG or IgM; these methods allowed comparison of the immunologic profiles of the mothers and the infants. We compared ELIFA and IB with a commercial enzyme immunoassay (EIA) or in-house immunosorbent agglutination assay (ISAGA) for the detection of IgM or IgA. The performances of combinations of methods were also assessed. A cumulative sensitivity of 98% during a 1-year follow-up was obtained with the ELIFA plus ISAGA combination. Only one case of CT was missed by the ELIFA plus ISAGA combination, whereas three cases were missed by the IB plus ISAGA combination, even though 48% of patients with CT were treated with pyrimethamine-sulfonamides, which are known to inhibit antibody neosynthesis. A similar performance was obtained with either ELIFA or IB in combination with EIA. The difference in performance between ELIFA plus ISAGA and IB plus ISAGA was not statistically significant (P = 0.31), and we conclude that both combinations of tests can be used for the diagnosis of CT in newborns.

Multicenter evaluation of strategies for serodiagnosis of primary infection with Toxoplasma gondii

The diagnostic performance of single-serum assays for toxoplasma-specific immunoglobulin (Ig)M. IgA. IgG, and IgE antibodies and of different combinations of such antibody assays in 20 European reference centers was assessed. A panel of 276 sera, of which 73 came from patients who seroconverted within 3 months (acute infection), 49 from patients who had seroconverted 3-12 months earlier (convalescence), and 154 from subjects who had two IgG-positive samples obtained 12 months apart (past infection), was tested with 20 toxoplasma-antibody assays and 195 combinations. In general, every assay with high diagnostic sensitivity showed low diagnostic specificity, i.e. no assay performed alone could reliably distinguish acute from past infection. Furthermore, no single assay (or combination) could separate convalescence from the other stages of toxoplasma infection. However, excellent diagnostic performances were reached by sequential use of highly sensitive IgM assays and methods examining IgG avidity or stage specificity. IgA or IgM assays were less suitable for confirmation of toxoplasma-IgM positivity. This study documents the strength of test combinations in assessing the stage of toxoplasma infection.

[Toxoplasmosis serodiagnosis: comparison of Access Toxo IgM II assay compared to Axsym Toxo IgM and Vidas Toxo IgM assays]

The Access Toxo IgM II test (Beckman Coulter Inc) was evaluated on 1,190 samples from toxoplasmosis serology requests, documented seroconversions, umbilical cord blood or venous blood from healthy newborn, and from newborns with congenital toxoplasmosis. Results were compared to those obtained with Vidas (bioMérieux) and Axsym (Abbott) assays, with Isaga as confirmatory technique. Results obtained with the Access test well correlate those with the Vidas (98.3%) and the Axsym (97.6%) assays. Less "bordeline" results are also observed with the Access test (0.22% versus 0.56% and 1.24% with Vidas and Axsym assays respectively). Results obtained from seroconverted patients prove that the Access assay is more sensitive than Vidas and Axsym assays, with respectively 2 and 4 samples detected earlier for 28 cases studied (recently seroconverted patients). Results obtained using prospective samples and with sequential sera obtained from patients with seroconversion clearly demonstrate that Access Toxo IgM II assay is perfectly adapted to toxoplasmosis diagnosis.

Diagnosis of congenital toxoplasmosis in the neonatal period: A multicenter evaluation

OBJECTIVE

To evaluate different laboratory tests used to diagnose congenital toxoplasmosis in the neonatal period.

STUDY DESIGN

A retrospective multicenter study of 294 pregnant women who experienced seroconversion for Toxoplasma gondii and subsequently delivered live-born infants. Fetal infection was assessed via specific IgM and IgA antibodies (cord and neonatal blood) and detection of T gondii in placenta and cord blood by mouse inoculation.

RESULTS

Ninety-three (32%) of the 294 infants were congenitally infected. The sensitivity of IgA in cord blood and in neonatal blood was 64% and 66%; the sensitivity of IgM was 41% and 42%, respectively. Mouse inoculation of the placenta and cord blood had sensitivities of 45% and 16%. Positive results of the serologic tests in congenitally infected children correlated significantly with the gestational age at the time of maternal infection but was not significantly influenced by the administration of specific antiparasitic treatment during pregnancy.

CONCLUSION

Specific T gondii IgA antibody is a more sensitive test than IgM for detecting congenital toxoplasmosis in the neonatal period. The overall specificity is better for serologic tests performed on neonatal blood than for those on cord blood. Neonatal screening with IgM or IgA antibodies will not detect the majority of children with congenital toxoplasmosis when the maternal infection occurred before the 20th week of pregnancy.

Prenatal diagnosis of congenital toxoplasmosis: a multicenter evaluation of different diagnostic parameters

OBJECTIVE

Our purpose was to evaluate different methods of diagnosing congenital toxoplasmosis prenatally by amniocentesis and cordocentesis.

STUDY DESIGN

In a retrospective multicenter study, we investigated consecutive women who had seroconversion for Toxoplasma gondii during pregnancy and who underwent either amniocentesis or cordocentesis or both to obtain a prenatal diagnosis of fetal toxoplasmosis. Data were obtained from 122 patients recruited in 6 different European Toxoplasma reference centers. Infants born to these mothers were followed up until 1 year of age to confirm or exclude congenital toxoplasmosis. Sensitivity, specificity, positive predictive value, and negative predictive value were measured for the following parameters: (1) detection of the parasite in amniotic fluid by mouse inoculation, (2) detection of the parasite in amniotic fluid by in vitro cell culture, (3) detection of Toxoplasma deoxyribonucleic acid in amniotic fluid by a polymerase chain reaction assay, (4) detection of the parasite in fetal blood by mouse inoculation, (5) detection of specific immunoglobulin M antibodies in fetal blood, and (6) detection of specific immunoglobulin A antibodies in fetal blood.

RESULTS

The polymerase chain reaction test performed on amniotic fluid had the highest level of sensitivity (81%) and also a high level of specificity (96%). The combination of the polymerase chain reaction test and mouse inoculation of amniotic fluid increased sensitivity to 91%. The sensitivity of immunoglobulins M and A in fetal blood was 47% and 38%, respectively. In congenitally infected fetuses a negative correlation was observed between positive serologic parameters and gestational age at the time of maternal infection and at prenatal diagnosis.

CONCLUSION

Congenital toxoplasmosis is best predicted by prenatal examination with the combination of T gondii polymerase chain reaction and mouse inoculation of amniotic fluid. The role of cordocentesis in the diagnosis of congenital toxoplasmosis is limited.

Treatment of toxoplasmosis during pregnancy: a multicenter study of impact on fetal transmission and children's sequelae at age 1 year

OBJECTIVE

Toxoplasmosis during pregnancy can cause fetal infection, with unpredictable sequelae in later life. We measured the effects of prenatal antibiotic therapy on the fetomaternal transmission of Toxoplasma gondii and on the appearance of sequelae in the congenitally infected child at age 1 year.

STUDY DESIGN

In a multicenter study we investigated consecutive women with Toxoplasma seroconversion during pregnancy. Data were obtained from 144 women recruited in 5 different Toxoplasma reference centers. Through multivariate analysis we assessed the association between transmission and appearance of sequelae as a function of the following parameters: estimated gestational age at infection, administration of antibiotic therapy, duration of antibiotic therapy, and time lapse between infection and the start of antibiotic therapy.

RESULTS

Sixty-four of the 144 women (44%) gave birth to a congenitally infected infant. Multivariate analysis showed that transmission was predicted neither by whether antibiotics had been administered nor by the time lapse between infection and the start of antibiotic therapy, but only by the gestational age at which maternal infection occurred (P <.0001). Sequelae were found in 19 children (13%), 9 of whom (6%) had severe sequelae. Administration of antibiotics was predictive of the absence of sequelae (P =.026, odds ratio 0.30, 95% confidence interval 0.104-0.863), in particular the absence of severe sequelae (P =.007, odds ratio 0.14, 95% confidence interval 0.036-0.584). The sooner antibiotics were given after the infection, the less frequently sequelae were seen (P =. 021).

CONCLUSION

Prenatal antibiotic therapy after toxoplasmosis during pregnancy had no impact on the fetomaternal transmission rate but reduced the rate of sequelae among the infected infants. The early start of treatment resulted in a significant reduction in the number of severely affected infants.

Bicentric evaluation of Access Toxo immunoglobulin M (IgM) and IgG assays and IMx toxo IgM and IgG assays and comparison with Platelia Toxo IgM and IgG assays

The recent Access immunoanalysis system (Sanofi Diagnostics Pasteur) for the serological diagnosis of toxoplasmosis was compared with the Abbott Toxo IMx EIA system, taking the Platelia Toxo immunoglobulin G (IgG) and Platelia Toxo IgM systems as references and using as confirmation methods an indirect fluorescence assay or a dye test for IgG and an immunosorbent agglutination assay (ISAGA) for IgM. A total of 1,461 serum samples were studied, of which 128 were collected from 42 recently seroconverted patients. Sensitivity and specificity rates of the Access system were 97.7 and 99.5%, respectively, for IgM and 98.6 and 100%, respectively, for IgG. Sensitivity and specificity rates of the Abbott IMx EIA system were 91 and 100%, respectively, for IgM and 92.5 and 100%, respectively, for IgG. The Access Toxo IgG and IgM EIA systems were found to be more sensitive than the Abbott Toxo IgG and IgM IMx EIA systems.

Detection of anti-toxoplasma immunoglobulin A antibodies by Platelia-Toxo IgA directed against P30 and by IMx Toxo IgA for diagnosis of acquired and congenital toxoplasmosis

Platelia-Toxo IgA and IMx Toxo IgA assays were used with 260 serum samples, of which 93 were from seroconverted patients, 58 were from 21 congenitally infected children, and 109 were from uninfected patients, to detect anti-P30 immunoglobulin A antibodies. Because of its enhanced sensitivity, Platelia-Toxo IgA is more efficient in diagnosing acute or congenital toxoplasmosis. IMx Toxo IgA must not be used to diagnose congenital toxoplasmosis.

Multiple B-cell epitopes in a recombinant GRA2 secreted antigen of Toxoplasma gondii

Two cDNA clones encoding the GRA2 (G.P.28.5) secreted antigen of Toxoplasma gondii were expressed in Escherichia coli as glutathione-S-transferase fusion polypeptides. A high level of expression was obtained for the first clone expressing the 59C-terminal amino acids of GRA2. The other one was an open-reading-frame of 212 amino acids containing the entire GRA2 cDNA. By ELISA, IgG antibodies directed against the 59aa recombinant polypeptide were detected in 33/44 (75%) sera from patients chronically infected with T. gondii and in 19/23 (82.6%) sera derived from patients with acute, primary toxoplasmosis. 10 of the 11 "chronic" sera which were negative by the 59aa ELISA were tested in a immunoblot against the 212aa open-reading-frame of GRA2: 8/10 were positive. A peptide representing the 15 C-terminal amino acids of GRA2 has been shown to contain the epitope recognized by a mouse monoclonal antibody (TG17-179). The reactivity of human sera with the 59aa recombinant polypeptide was inhibited to varying degrees when the sera were co-incubated with this peptide. Twelve chronic sera showed a range of inhibition from 8 to 100% and twelve acute sera an inhibition range of 15 to 90%. This suggests that the 15aa C-terminal peptide contains an epitope recognized in both the acute and chronic phases of infection and that other major epitope(s) exist in the 59aa C-terminal region of GRA2. As a conclusion, the recombinant GRA2 protein appears to contain at least three B-cell epitopes.

BioArgos: a fully automated blood culture system

BioArgos (Sanofi Diagnostics Pasteur, Marnes-la-Coquette, France) is a fully automated blood culture system that detects carbon dioxide production by infrared spectroscopy through a glass bottle. This hands-off system was compared with the BACTEC NR-660 system (Becton Dickinson Diagnostic Instrument Systems, Towson, Md.). A total of 336 microorganisms belonging to 74 taxa were tested in simulated blood cultures by both systems. Experimental data showed no significant differences between the two systems. The inclusive detection times (+/- the standard deviations) were 33.2 +/- 28.7 and 35.0 +/- 30.6 h with BioArgos and BACTEC, respectively. Anaerobes were detected earlier with BioArgos, whereas detection of some organisms that need oxygen to grow was slightly delayed. In conclusion, BioArgos is as reliable and accurate as BACTEC NR-660 and shows better practicability owing to noninvasive detection, reduction of vial manipulation, and absence of daily maintenance.

Secretion of Toxoplasma gondii-specific antibody in vitro by peripheral blood mononuclear cells as a new marker of acute toxoplasmosis

Antigen-specific antibody secretion in vitro by peripheral blood mononuclear cells (PBMC) reflects an in vivo stimulation of the immune system by the antigen. Primary infection of immunocompetent patients with T. gondii causes an acute infection followed by chronic toxoplasmosis. We examined in vitro anti-Toxoplasma antibody production by PBMC during the acute and chronic phases of toxoplasmosis. PBMC from patients with acute or chronic toxoplasmosis and seronegative subjects were cultured for up to 6 days. Anti-Toxoplasma antibodies were assayed in supernatants by ELISA and immunoblotting. Anti-Toxoplasma antibodies were detected in supernatants of PBMC from 29 pregnant women who seroconverted during gestation. PBMC from 17 patients who had chronic toxoplasmosis and PBMC from 10 seronegative healthy controls did not secrete Toxoplasma-specific antibodies. This in vitro antibody secretion was spontaneous, active and transient since it disappeared between 11 and 24 weeks after seroconversion. Anti-Toxoplasma antibody secretion by PBMC from patients with acute toxoplasmosis is consistent with an in vivo stimulation of the immune system by T. gondii antigens. Our results represent a new approach for studying the immunological response during T. gondii infection and could have important implications for the diagnosis of acute and re-activated toxoplasmosis.

Anti-P30 IgA antibodies as prenatal markers of congenital toxoplasma infection

This study extends a previous study and confirms that the detection of anti-P30 IgA antibodies is very helpful in the diagnosis of acute acquired or congenital toxoplasmosis. Moreover, we demonstrate that an anti-P30 IgA response can be mounted in the fetuses infected by Toxoplasma gondii during their intra-uterine life as early as week 23 of gestation. A double-sandwich ELISA described in our previous work was used to detect anti-P30 IgA antibodies in 1378 human serum samples collected from 551 patients, including 162 fetuses whose mothers had been infected by T. gondii during pregnancy, 46 congenitally infected and 90 uninfected newborns and 253 women suspected of having been infected during pregnancy, including the mothers of fetuses and newborns previously described. Anti-P30 IgA antibodies were detected in all cases of acute toxoplasmosis but in no case of chronic toxoplasmosis: in the majority of cases, the IgA antibody titre fell below cut-off in 3-9 months. Among the 46 congenitally infected newborns, anti-P30 IgA antibodies were detected in sera of 41 infected newborns (38 at birth, two in the first months of life, one in the seventh month of life), while anti-P30 IgM antibodies were detected in only 30 cases at birth and in one case during the first month of life. Among 162 fetuses, anti-P30 IgA response was observed in five infected fetuses, but was not detected in either 152 uninfected fetuses or in five fetuses considered as infected. The absence or presence of anti-P30 IgA antibodies in the fetus is discussed in relation to the date of maternal infection and collection of the fetal blood. It clearly appears from our study that the combined testing of both IgM and IgA in the fetus and the newborn is essential for a more efficient diagnosis of infection.

Platelia-Toxo IgA, a new kit for early diagnosis of congenital toxoplasmosis by detection of anti-P30 immunoglobulin A antibodies

With the aim of achieving earlier diagnosis of congenital toxoplasmosis, anti-P30 immunoglobulin A (IgA) antibodies were assayed by using a Platelia-Toxo IgA kit with samples from 72 children born to mothers who seroconverted during pregnancy. A total of 148 serum samples and 1 cerebrospinal fluid samples were from 23 congenitally infected children (2 serum samples were collected from fetuses), and 74 serum samples were from 49 uninfected children. Among the 23 infected children, anti-P30 IgA antibodies were present in all infants either at birth or in the following weeks, whereas anti-P30 IgM antibodies were present in 13 from the 23 infected children either at birth or in the following weeks. Serum samples collected in utero from two infected children were also tested. One of these samples was positive for both anti-P30 IgA and anti-P30 IgM antibodies, whereas both children were negative at birth for these antibodies. Neither anti-P30 IgA nor anti-P30 IgM antibodies were detected in 47 of 49 uninfected children. These results suggest that detection of anti-P30 IgA antibodies by the Platelia-Toxo IgA kit is a very effective method for early diagnosis of congenital toxoplasma infection.

Identification and biochemical characterization of antigens of tachyzoites and bradyzoites of Toxoplasma gondii with cross-reactive epitopes

The aim of the present work was the identification and biochemical characterization of antigens from the tachyzoite and bradyzoite stages of Toxoplasma gondii that share cross-reactive epitopes. Our previous work has demonstrated the induction by tachyzoite excreted-secreted antigens of both a humoral and a cell-mediated protective response. We investigated the question as to whether some bradyzoite and tachyzoite (excreted-secreted, soluble or membrane) antigens share cross-reactive epitopes. Using immunoprecipitation techniques, we identified four tachyzoite antigens with molecular weights of 63, 43, 39, and 28.5 kDa, which were recognized both by sera raised against tachyzoite antigens and by chronic-phase human sera with residual IgG antibodies. In an attempt to define the biochemical nature of these antigens, we show that the 43- and 28.5-kDa antigens seem to be glycosylated since they bind to concanavalin A, as does a 37-kDa tachyzoite antigen.

IgA antibodies against P30 as markers of congenital and acute toxoplasmosis

Specific IgA antibodies against P30, a major surface protein of Toxoplasma gondii were sought in 198 serum samples (from 133 patients) by means of a double-sandwich enzyme-linked immunosorbent assay. These antibodies were detected in all cases of acute toxoplasmosis but in no cases of chronic toxoplasmosis nor in seronegative patients. They were not detected in samples from patients with "natural IgM antibodies" or in those containing rheumatoid factor or antinuclear antibodies. Among 26 infants whose mothers were infected during pregnancy, anti-P30 IgA antibodies were exclusively detected in the samples from the 8 infected infants, although anti-P30 IgM antibodies were detected in only 3 of the infected infants. No uninfected infant had IgA, though 5 had IgM at birth. Thus, the detection of IgA anti-P30 antibodies seems a better means than the detection of IgM antibodies of identifying infected infants, which is very important for treatment. In addition, the very early detection of IgA antibodies may be important for the diagnosis of acute toxoplasmosis, especially during pregnancy and perhaps also in patients infected by human immunodeficiency virus.

Induction of a protective antibody-dependent response against toxoplasmosis by in vitro excreted/secreted antigens from tachyzoites of Toxoplasma gondii

Toxoplasma gondii is a worldwide protozoan parasite which causes severe disease in congenitally infected children and in immunocompromised patients. Besides the well-defined cytoplasmic and membrane antigens of tachyzoites, we felt that excreted/secreted antigens could play a major role in the immune response. We first report the development of a well-controlled procedure for obtaining tachyzoite excreted/secreted antigens (E/SA) in cell-free incubation media. The E/SA immunogenic in human, rat and mouse toxoplasmosis were then characterized. The major E/SA recognized by human sera from the chronic phase of toxoplasmosis had molecular weights of 108, 97, 86, 69, 60, 57, 42, 39, 28.5, 27 and 26 kD. When injected into +/+ Fischer rats, E/SA elicited high antibody titres. In addition, passive transfer of these sera to highly susceptible nu/nu littermates induced a significant degree of protection towards the virulent RH strain of T. gondii. This work, which demonstrates the key role played by E/SA in the protective immune response, suggests that these antigens should be of value both for diagnostic purposes and for the development of new strategies for immunization against toxoplasmosis.

Recognition of Toxoplasma gondii excreted and secreted antigens by human sera from acquired and congenital toxoplasmosis: identification of markers of acute and chronic infection

While the serological response to somatic antigens of Toxoplasma gondii is currently analysed, little information is available on the antibody response to the antigens excreted and secreted by tachyzoïtes (ESA). This serological study is focused on the immune response towards these antigens which were released by the parasites in cell-free culture medium. Human sera corresponding to 'acute', 'subacute' and 'chronic' acquired infection and sera from infected newborns and from their mothers were analysed by radio-immunoprecipitation with 35S methionine-labelled ESA and with radio-iodinated membrane antigens followed by polyacrylamide gel electrophoresis. In chronic toxoplasmosis, IgG antibodies recognized among ESA major 108, 97, 86, 60, 57, 42, 39 and 28.5 kD antigens; the 108-97 kD doublets and the 28.5 kD antigen seemed characteristic of the chronic phase of toxoplasmosis. In acute infection, IgM antibodies to the 97 kD antigen, the first to appear, seem to contitute good markers of early acute infection. The comparative study of antibody response to membrane antigens showed that, in chronic toxoplasmosis, human sera recognized four antigens of 43, 35, 30 and 22 kD and that, in acute toxoplasmosis, they first recognized the 43 and 30 kD antigens. The serological evolution in congenital toxoplasmosis was the same as in acquired infection. In some cases, the serological profile of the newborn was different from that of his mother, with an additional antibody response to a 170 kD antigen. This study demonstrates in human toxoplasmosis an early, intense and characteristic antibody response against ESA, suggesting that the use of these antigens could lead in the future to improved diagnostic tests.

Double-blind study of glaucine in chronic cough

Thirty-eight patients, affected by chronic cough and hospitalized in 14 different rooms, entered a double-blind cross-over trial aimed at evaluating efficacy and tolerance of single oral doses of glaucine (eo mg) versus single oral doses of codeine (30 mg) and placebo. Patients occupying the same room were administered on 3 consecutive nights, and an objective evaluation of efficacy was ensured by means of a tape recorded. The mean cough counts during the 8-h interval after drug administration were 269.3 after placebo, 241.8 after glaucine, and 201.9 after codeine (p less than 0.05). The antitussive effects of glaucine and codeine were practically superimposable up to the 6th h, when glaucine effect declined. Treatments were well tolerated by all the patients, they themselves were not able to detect any difference in cough suppression among the three treatments.