PubMed Health⌕ Search

Biomedical subjects

F Freymuth

Publications and source records attributed to F Freymuth.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Evaluation of four commercial immunoglobulin G (IgG)- and IgM- specific enzyme immunoassays for diagnosis of Mycoplasma pneumoniae infections].

The four following commercially available enzyme immunoassays (EIAs) were assessed and compared for their performance in detecting Mycoplasma pneumoniae specific IgG and IgM antibodies: EIA-Platelia, EIA-Bmd, EIA-Sorin and EIA-Biotest. Three groups of patients were investigated: 39 patients (27 children and 12 adults) with respiratory infections and a M. pneumoniae PCR-positive in respiratory specimens (group I; 52 sera), 61 healthy children and adults (group II; 61 sera) and 20 patients with rheumatoid factor, antinuclear antibodies or positive antiviral IgM (group III; 20 sera). In group III, the IgM specificity for the EIA-Platelia, EIA-Bmd, EIA-Biotest and EIA-Sorin was 100%, 90%, 65% and 25%, respectively. In the children from group I, the four EIAs had similar IgM sensitivity (89 to 92%) but a striking difference in IgM sensitivity was observed in adult patients: 16% EIA-Platelia and EIA-Bmd, 50% EIA-Biotest, 58% EIA-Sorin. The sensitivity for IgG was greater with EIA-Bmd and EIA-Biotest, especially in detection of IgG in acute-phase serum : 61% EIA-Bmd and EIA-Biotest, 15% EIA-Platelia and 31% EIA-Sorin. Discrepant and unexpected results were observed in IgM detection from control healthy patients using EIA-Sorin and EIA-Biotest, confirming the lack of specificity of these two EIA-tests and making them inaccurate for routine diagnosis. A high IgG seroprevalence were found in healthy adults by the four EIAs (43-70%). In healthy children, EIA-Bmd and EIA-Biotest gave a higher IgG seroprevalence than EIA-Sorin and EIA-Platelia (45% each for the former as compared to 17% and 20%, respectively, for the latter).These results confirm that the IgM EIA serology test is a valuable tool for the early diagnosis of M. pneumoniae infections in children, as long as the EIA test used is specific. In adults, the difficult interpretation of EIA tests suggests that paired sera, combined with PCR detection on respiratory tract specimens collected on admission of patient, should be required for accurate diagnosis.

Adult↗
PubMed2002

[Sudden death of a two-year-old boy with influenza A virus infection: study of an autopsy case].

UNLABELLED: Influenza A virus infections are common in childhood and infancy and are often underdiagnosed while serious or lethal forms are rare. CASE-REPORT: We describe a case of sudden death in a two-year-old boy. Pathologic findings at autopsy were consistent with Myxovirus influenzae A virus infection and the virus was isolated by post mortem PCR. CONCLUSION: In the case of sudden death in infants, especially if pathologic findings are compatible with a viral infection, PCR may allow identification of the causative virus.

Autopsy↗
PubMed2002

[Role of viral infections and Chlamydia pneumoniae and Mycoplasma pneumoniae infections in asthma in infants and young children. Epidemiologic study of 118 children].

Wheezing associated with upper respiratory tract infections is common in children. Using conventional techniques (viral culture and immunofluorescence) and molecular techniques (PCR), we studied the prevalence of viral, Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) infections in 118 children hospitalised for acute asthma exacerbation. A virus was identified by conventional techniques in 40 of the 118 nasal swabs (34%), while PCR allowed identification of virus CP and MP in 80 samples (68%). Combination of both techniques allowed identification of an infectious agent in 91 cases (77%). More than one agent was isolated in 15 cases (23%). Rhinovirus (RV) (45%) were prevalent, followed by respiratory syncytial virus (RSV) (28%) and enterovirus (8.5%). RV and RSV have a similar prevalence (42% and 36% respectively) before two years of age, as compared with 66% and 27% respectively in older children. CP and MP were identified by PCR in only 6 cases. Molecular techniques of identification demonstrated a clear advantage in sensitivity compared with conventional techniques. The high prevalence of RV and RSV infections is remarkable, while CP and MP do not seem particularly involved in children acute asthma exacerbation.

Asthma↗
PubMed2002

Evaluation of four commercial immunoglobulin G (IgG)- and IgM-specific enzyme immunoassays for diagnosis of Mycoplasma pneumoniae infections.

The four following commercially available enzyme immunoassays (EIAs) were assessed and compared for their performance in detecting Mycoplasma pneumoniae immunoglobulin G (IgG)- and IgM-specific antibodies Platelia EIA, ImmunoWELL M. pneumoniae ELISA IgG and IgM, ETI-MP-IgG and IgM EIAs and Biotest anti-M. pneumoniae IgG and IgM ELISA (referred to herein as EIA-Platelia, EIA-BMD, EIA-Sorin, and EIA-Biotest). Three groups of patients were investigated: 39 patients (27 children and 12 adults) with respiratory infections who tested positive by PCR for M. pneumoniae in respiratory specimens (group I; 52 serum samples), 61 healthy children and adults (group II; 61 serum samples), and 20 patients with rheumatoid factor or antinuclear antibodies, or who tested positive for antiviral IgM (group III; 20 serum samples). In group III, the IgM specificity for EIA-Platelia, EIA-BMD, EIA-Biotest, and EIA-Sorin was 100, 90, 65, and 25%, respectively. In the children from group I, the four EIAs had similar IgM sensitivities (89 to 92%); the sensitivity for IgG was greater with EIA-BMD and EIA-Biotest than with EIA-Platelia and EIA-Sorin (66 and 78% versus 55 and 52%, respectively). In adult patients from group I, 9 to 10 serum samples were positive for IgG with a concordant sensitivity of 75 to 83% between the four EIAs but a striking difference in IgM sensitivity: 16% by EIA-Platelia and EIA-BMD, 50% by EIA-Biotest, and 58% by EIA-Sorin. Discrepant and unexpected results were observed in IgM detection from control healthy patients using EIA-Sorin and EIA-Biotest, confirming the lack of specificity of these two EIAs and making them inaccurate for routine diagnosis. A good concordance of IgG seroprevalence in healthy adults was found between the four EIAs (66 to 70%), though this concordance was lower with EIA-Platelia (43%). In healthy children, EIA-BMD and EIA-Biotest gave a higher IgG seroprevalence than EIA-Sorin and EIA-Platelia (45% each for the former compared to 17 and 20%, respectively, for the latter). These results confirm that the IgM EIA serology test is a valuable tool for the early diagnosis of M. pneumoniae infections in children, as long as the EIA used is specific. In adults, the difficult interpretation of EIAs suggests that paired sera, combined with PCR detection on respiratory tract specimens collected on admission of patient, should be required for accurate diagnosis.

Adult↗
PubMed2002

Real-time PCR quantification of human cytomegalovirus DNA in amniotic fluid samples from mothers with primary infection.

A real-time PCR assay was developed to quantify human cytomegalovirus (HCMV) DNA in amniotic fluid (AF) samples collected from 30 pregnant women with primary HCMV infection as detected either from HCMV-immunoglobulin G (IgG) seroconversion or by the presence of HCMV-specific IgG and IgM associated with a low IgG avidity. Clinical information available for each case included ultrasonographic examination and fetal or newborn outcome. HCMV infection of fetuses or newborns was confirmed for the 30 studied cases. AF samples were subdivided into three groups. In group A (n = 13), fetuses presented major ultrasound abnormalities, and pregnancy was terminated. In group B (n = 13), fetuses had normal ultrasound findings, the pregnancy went to term, and the newborns were asymptomatic at birth. In group C (n = 4), fetuses had no or minor ultrasonographic signs, and pregnancy was terminated. The HCMV DNA load values in AF samples were significantly higher in group A (median, 2.8 x 10(5) genome equivalents [GE]/ml) than in group B (median, 8 x 10(3) GE/ml) (P = 0.014). Our findings suggest that HCMV load level in AF samples correlates with fetal clinical outcome but might also be dependent on other factors, such as the gestational age at the time of AF sampling and the time elapsed since maternal infection.

Amniotic Fluid↗
PubMed2001

Direct diagnosis of human respiratory coronaviruses 229E and OC43 by the polymerase chain reaction.

An RT-PCR-hybridization was developed that amplified genetic material from the M protein gene of HCoV-229E and HCoV-OC43. The analytic sensitivity of these original primers were compared with primers defined in the N gene and described previously. The results show that 0.05 TCID50 of HCoV-229E and 0.01 TCID50 of HCoV-OC43 can be detected by this molecular method using the original method. Detection of HCoV-229E and HCoV-OC43 in clinical specimens is possible using this method: 348 respiratory specimens (202 sputum and 146 nasal aspirates) were tested with this RT-PCR-hybridization and 12 human coronavirus are detected (3%). The method could provide a useful tool for demonstrating the role of human coronavirus in infections of the respiratory tract.

Cell Line↗
PubMed2001

Congenital HCMV infection: a collaborative and comparative study of virus detection in amniotic fluid by culture and by PCR.

Cytomegalovirus (HCMV) infection is the leading cause of congenital virus infection in developed countries, affecting an estimated 1% of births. This antenatal infection can cause serious sequelae. Strategies for prevention and treatment must, therefore, be agreed upon, entailing a preliminary performance assessment of antenatal virus diagnosis techniques. Between 1992 and 1999, HCMV serology status was established for 19456 pregnant women in four French hospitals. Seronegative patients (55.4%) were given serology screening, and antenatal diagnosis was given to 152 women who had shown seroconversion during their pregnancies (1.4%). The detection of HCMV transmission from mother to fetus was finally established in 95 cases, using polymerase chain reaction (PCR) and viral culture methods for detecting HCMV in the amniotic fluid. These results were compared with viral culture of children's urine after birth, enabling us to distinguish between children really infected in utero (30%) and non-infected children (70%). The results of the virus culture and those of PCR were identical in 94 of the 95 cases, with one discrepancy (culture-/PCR+). The two diagnosis techniques had identical sensitivity (72%), with culture proving slightly more specific than PCR (98.4% as opposed to 96.9%). Positive prediction values for culture and for PCR were, respectively, 95.6 and 91.3%. Antenatal virus diagnosis on amniotic fluid was negative with both techniques in 8 out of 29 cases of children born with HCMV infection (VPN=89%). Over half of these wrongly negative results can be explained by amniocentesis carried out too early in the pregnancy or too early with respect to the mother's primary infection.

Amniotic Fluid↗
PubMed2001

Early diagnosis of adenovirus infection and treatment with cidofovir after bone marrow transplantation in children.

Adenovirus infection remains an important cause of mortality after bone marrow transplantation (BMT). Currently no efficient antiviral treatment is known. Thus, testing new modalities of early diagnosis and treatment is a crucial objective. Adenovirus infection is defined by the combination of symptoms and the isolation of virus from the source of clinical symptoms. The involvement of two or more organs and the presence of virus in blood cultures define disseminated disease. Seven children with a median age of 7 years received bone marrow transplantation for leukemia. All received an unrelated graft without T cell depletion. Adenovirus was sought in blood, urine and biopsy specimens using PCR and culture. Analysis of biopsy specimens included systematic immunohistochemistry. Cidofovir treatment was initiated as soon as biopsy revealed the histopathological signs of adenovirus. Cidofovir was given at 5 mg/kg once weekly for 3 weeks then every 2 weeks. Six patients had diarrhoea and one patient had cystitis. Adenovirus infection and disseminated disease were diagnosed in four cases and three cases, respectively. In six cases, serotype A31 was isolated from gastrointestinal biopsy and in two cases serotypes B2 and C6 were detected in blood and urine. Cidofovir treatment was associated with clinical improvement of diarrhoea, cystitis and fever in five patients, in whom the virus became undetectable in cultures and PCR analyses despite the persistence of immunodeficiency. The median follow-up was 360 days after BMT (240-570). One child died of invasive aspergillosis and another of disseminated adenovirus after interruption of cidofovir therapy. Further studies in immunocompromised patients will be needed to extend these promising results concerning the role of cidofovir in adenovirus infection.

Adenovirus Infections, Human↗
PubMed2001

Multicenter evaluation of a rapid and convenient method for determination of cytomegalovirus immunoglobulin G avidity.

An easy, rapid, and reproducible test to distinguish residual cytomegalovirus (CMV) immunoglobulin M (IgM) antibodies from antibodies produced in primary infection could be useful, especially for pregnant women. The CMV avidity of IgG antibodies with the VIDAS automated enzyme-linked fluorescent assay and 6 M urea was evaluated in a multicenter study to differentiate between primary CMV infections and past infections or reactivations. A total of 416 serum specimens were tested: 159 specimens were from follow-up of primary infections, and 257 were from past infections. All of the specimens from primary infections collected within 4 months (17 weeks) after the onset of the infection had an avidity index lower than 0.8. An avidity index higher than 0.8 excludes a recent primary infection of less than 4 months. However, an avidity index higher than 0.8 cannot confirm all past infections, since 48 specimens (18%) from past infections had an avidity index lower than 0.8 (between 0.5 and 0.8). The exclusion capacity could be improved (96.9%) by using a cutoff of 0.7, but this index would decrease the specificity of the technique, since the avidity index was found to be between 0.7 and 0.8 in two patients with recent primary infection. All specimens from primary infections obtained more than 4 months after the onset of infection had an avidity index more than 0.2. In this study, an avidity index less than 0.2 confirms the presence of a recent primary infection of less than 4 months. The VIDAS CMV IgG avidity test is a rapid, reproducible test with very good performance.

Antibodies, Viral↗
PubMed2001

[Epidemiology of respiratory virus infections].

Respiratory viral infections are very common in young children. They sometimes occur as primary infections (and sometimes re-infections) by influenza and parainfluenza virus, respiratory syncytial virus (VRS), adenovirus, rhinovirus and coronavirus. The clinical pictures are very varied and without strict clinico-virological correlation. In adults the role of the site (frail lung, aged persons) and the type of virus play an important part. Many viral infections develop in an epidemiological way (influenza, VRS bronchiolitis, rhinovirus infections...) and several epidemics by different viruses overlap from September-October to March-April making it very difficult to decide the precise cause. Epidemics are followed thanks to networks of medical practitioners (GROG, SENTINELLE...) and by data from hospitalised patients, but precise identification of epidemic viruses is only possible and validated by virological analysis of samples taken from patients.

Adenoviridae Infections↗
PubMed2000

Comparison of three non-nested RT-PCR for the detection of influenza A viruses.

BACKGROUND: The viral isolation technique (VIT) is largely used as a gold standard for the detection of influenza A and B viruses in respiratory samples. Some recent studies have pointed out that the polymerase chain reaction (PCR) assays allow sensitive and rapid detection of influenza viruses, also providing excellent correlation with traditional methods. OBJECTIVES AND DESIGN STUDY: The aim of this study was to evaluate the efficiency of three non-nested PCR, two PCR-hybridization assays using primers defined in M and NS genes, and one PCR which uses primers defined in NP, NS and HA genes and combines the detection of H3N2 and H1N1 hemagglutinin genes using defined primers in NP, NS and HA genes (PCR3), in comparison with an IF assay (IFA) and viral isolation technique (VIT). The study was carried out on 244 nasal samples collected mainly by practitioners of the GROG surveillance network during winter 1998-1999 for the detection of influenza A virus. RESULTS: Overall influenza viruses were detected more frequently by PCR techniques in 157 (64.3%), 147 (60.2%), 110 (45%) cases for PCR1, PCR2, PCR3, respectively, than by VIT or IFA, in 100 (40.9%) and 74 (30.3%) cases, respectively. Taking the positive culture samples as a reference, 100 (41.8%) samples were found to be positive for influenza A, and the sensitivity of IFA, PCR 1, PCR 2 and PCR3 techniques were 70, 100, 99, and 90%, respectively as compared with viral isolation cultures. On the other hand, as 86.5% of positive samples were positive with at least two different techniques, the sensitivity, specificity, VPP and VPN of each technique were recalculated taking into account a further criterion defining a positive sample: positivity with two techniques. We observe that techniques PCR 2 and particularly PCR 1 have very good sensitivity, respectively 98.6 and 100%, far better than the traditional techniques, IFA and culture, whilst maintaining acceptable specificity: 94.1 and 86.1%, respectively. In both cases they enable 141 (57.7%) A-positive influenza samples to be detected instead of the 100 (40.9%) obtained when culture is the reference test. IFA, culture and PCR 3 are highly specific (VPP=100%), but in comparison with PCR 1 and 2 their sensitivity, respectively 51.7, 69. 9, 77.6%, and negative predictive value are unsatisfactory. PCR 1 and 2 are superior to the other techniques to a statistically highly significant degree in terms of sensitivity, but the difference between the two is not significant.

Adolescent↗
PubMed2000

Plasma cytomegalovirus DNA, pp65 antigenaemia and a low CD4 cell count remain risk factors for cytomegalovirus disease in patients receiving highly active antiretroviral therapy.

OBJECTIVE: To study the natural history and the current risk factors for cytomegalovirus (CMV) disease in the context of highly active antiretroviral therapy (HAART). SETTING: Prospective multicentre cohort in 15 university hospitals in France. METHODS: A group of 198 patients with CD4 cell count < 100 x 10(6) cells/l (or < 200 x 10(6) cells/l under HAART for at least 2 months), no previous CMV disease and CMV-positive serology were followed every 4 months clinically and for virological testing including HIV RNA and CMV blood markers (culture, pp65 antigenaemia, plasma CMV DNA and CMV late mRNA by the polymerase chain reaction). RESULTS: At inclusion, median CD4 was 77 x 10(6) cells/l (0-308) and 85% of the patients received protease inhibitors. The percentage of patients receiving HAART reached 99% at 12 months. After a follow-up of 23.6 months, the incidence of CMV disease was 3.2/100 patient-years [95% confidence interval (CI) 1.3-5.0]. In univariate Cox models, all the CMV markers, a CD4 cell count remaining < 75 x 10(6) cells/l and an HIV viral load > 100,000 copies/ml were predictive for CMV disease. The hazard ratios for CMV disease were 11 for blood culture; 14 and 70 for pp65 antigenaemia of > or = 1 and > or = 100 nuclei/200,000 cells, respectively; 35 for plasma CMV DNA; 6 for CMV mRNA; 29 for CD4 < 75 x 10(6) cells/l; and 12 for HIV RNA > 100,000 copies/ml. In a stepwise multivariate analysis, only three covariates were independently associated with the occurrence of a disease: plasma CMV DNA, pp65 antigenaemia > or = 100 nuclei/200,000 cells and a CD4 count < 75 x 10(6) cells/l. CONCLUSION: CMV blood markers and CD4 count < 75 x 10(6) cells/l remain risk factors for CMV disease in patients receiving HAART. Analysis of plasma CMV DNA by the polymerase chain reaction is a reproducible and standardized tool that could be used as a decision marker for initiating CMV pre-emptive therapy.

AIDS-Related Opportunistic Infections↗
PubMed2000

[Viral co-infections in immunocompetent infants with bronchiolitis: prospective epidemiologic study].

The nature of viral infection was prospectively investigated in 202 immunocompetent infants with bronchiolitis. Nasal aspirates were evaluated by immunofluorescence assay, viral isolation technique and polymerase-chain-reaction-hybridization assay. In 55 infants (27%) more than one respiratory virus were detected. A Rotavirus was found in 40 infants (20%), without any relationship with the respiratory viral status, respiratory syncytial virus being the main virus (46/55), and the association of respiratory syncytial virus and adenovirus being the most frequent (21/55). No difference was found between monoviral infections on the one hand and simultaneous viral infections on the other hand according to age, weight, neonatal disease, past history of personal or familial atopy, central temperature, Silverman's index, oxygen dependency, length of hospitalization, microbiology data. There was no indication that simultaneous virus infections were associated with an increased severity of the bronchiolitis in immunocompetent infants.

Adenoviridae Infections↗
PubMed1999

[Respiratory allergy and the viruses].

Viral respiratory tract infections are a major cause of wheezing in infants. Investigators determined that 80% to 85% of school-aged children with wheezing episodes were tested positive for virus. To more fully understand how viral respiratory tract infections influence asthma, investigators have evaluated the effect of respiratory tract infections on airway symptoms, function, and inflammation. Although the mechanisms by which respiratory viruses enhance lower airway inflammation are not established, cytokines may play a key role in this process. The respiratory epithelial cell is a principal host for respiratory virus replication and is likely to be the first source of cytokines during an acute infection. T cells orchestrate immune responses to both allergens and viruses, and regulate effector cells with virucidal and proinflammatory effects. Although studies demonstrate that virus-specific T cells may contribute to virus-induced lung disease, evidence to define the role of virus-specific T lymphocytes in asthma has not been fully established. Some infections early in life may also have an important immunoregulary role in the subsequent development of allergy and asthma. Atopy is characterised by exaggerated Th-2 cell responses to common allergens with secretion of cytokines such as IL-4 and IL-5 that promote IgE production and eosinophil activation. In contrast, childhood infections typically induce a Th-1 cell response, characterised by secretion of interferon-gamma, which enhances the antiviral activities of effector cells. These two types of T cell responses are mutually antagonistic.

Acute Disease↗
PubMed1999

Detection of viral, Chlamydia pneumoniae and Mycoplasma pneumoniae infections in exacerbations of asthma in children.

BACKGROUND: A high frequency of virus infections has been recently pointed out in the exacerbations of asthma in children. OBJECTIVES: To confirm this, using conventional and molecular detection methods, and expanding the study to younger children. STUDY DESIGN: One hundred and thirty-two nasal aspirates from 75 children hospitalized for a severe attack of asthma were studied (32 infants, mean age 9.1 months; and 43 children, mean age 5.6 years). According to the virus, a viral isolation technique, immunofluorescence assays (IFA) or both were used for the detection of rhinovirus, enterovirus, respiratory syncytial (RS) virus, adenovirus, coronavirus 229E, influenza and parainfluenza virus. Polymerase chain reaction (PCR) assays were used for the detection of rhinovirus, enterovirus, RS virus, adenovirus, coronavirus 229E and OC43, Chlamydia pneumoniae and Mycoplasma pneumoniae. RESULTS: Using IFA and viral isolation techniques, viruses were detected in 33.3% of cases, and by PCR techniques, nucleic acid sequences of virus, Chlamydia pneumoniae and Mycoplasma pneumoniae were obtained in 71.9% of cases. The combination of conventional and molecular techniques detects 81.8% of positive samples. Two organisms were identified in the same nasal sample in 20.4% of the cases. The percentage of detections was higher (85.9%) in the younger group than in the other (77%). The most frequently detected agents were rhinovirus (46.9%) and RS virus (21.2%). Using PCR rather than conventional techniques, the detection rates were increased 5.8- and 1.6-fold in rhinovirus and RS virus infections, respectively. The detection levels of the other organisms are as follows: 9.8, 5.1, 4.5, 4.5, 4.5, 3.7, and 2.2% for enterovirus, influenza virus, Chlamydia pneumoniae, adenovirus, coronavirus, parainfluenza virus, and Mycoplasma pneumoniae, respectively. CONCLUSION: These results confirm the previously reported high frequency of rhinovirus detection in asthmatic exacerbations in children. They also point out the frequency of RS virus detection, and emphasize the fact that PCR assays may be necessary to diagnose respiratory infections in asthma.

Adolescent↗