WHO international standard for anti-rubella: learning from its application.

The WHO international standard for anti-rubella was first established in the 1960s when clinical diagnostics were in their infancy. Since the endorsement of the first international standard for anti-rubella IgG (RUBI-1-94), new rubella vaccines have been developed and global coverage of rubella vaccination has increased. Methods used to measure concentrations of anti-rubella IgG have also evolved to rapid, high-throughput binding assays, which have replaced often cumbersome and highly technical functional assays. During this timeframe, the protective concentration of antibody was set at 10 IU/mL by extrapolation of functional assay correlates; however, the subpopulation of antibodies within a polyclonal serum that confer protection remained undefined. Anti-rubella assays have variable formats, including antigens used, such that the same clinical sample tested on different assays can report different values with potentially devastating consequences, such as recommending to terminate pregnancy. WHO convened a meeting of experts in the rubella field to discuss the use of RUBI-1-94 and the potential future role of this international standard. The main conclusions of this meeting questioned the appropriateness of 10 IU/mL as the cutoff for protection and acknowledged the continuing role of RUBI-1-94 as a reference preparation to address analytical sensitivity and assay variation.

Fetal and neonatal abnormalities due to congenital rubella syndrome: a review of literature.

OBJECTIVE: Rubella virus infection during the first trimester of pregnancy can cause congenital rubella syndrome (CRS). We aimed to describe the abnormalities in order to define the ultrasound features to look for when performing prenatal scans. The goal of this review is to focus specifically on the signs of CRS accessible to prenatal diagnosis. METHODS: We analyzed every case of CRS described before and/or after birth that we identified in the Pubmed database and classified them as accessible or not to prenatal diagnosis. RESULTS: The most frequently reported malformations accessible to prenatal diagnosis were: cardiac septal defects, pulmonary artery stenosis, microcephaly, cataract, microphtalmia, and hepatosplenomegaly. CONCLUSION: This extensive literature review shows that the ultrasound features of CRS are not well known, even though rubella was the first teratogenic virus described. This review will help clinicians in the management of rubella during pregnancy by clarifying the findings to be sought.

Assessing Immunity to Rubella Virus: a Plea for Standardization of IgG (Immuno)assays.

Immunity to rubella virus (RV) is commonly determined by measuring specific immunoglobulin G (RV IgG). However, RV IgG results and their interpretation may vary, depending on the immunoassay, even though most commercial immunoassays (CIAs) have been calibrated against an international standard and results are reported in international units per milliliter. A panel of 322 sera collected from pregnant women that tested negative or equivocal for RV IgG in a prior test (routine screening) was selected. This panel was tested with two reference tests, immunoblotting (IB) and neutralization (Nt), and with 8 CIAs widely used in Europe. IB and Nt gave concordant results on 267/322 (82.9%) sera. Of these, 85 (26.4%) sera were negative and 182 (56.5%) sera were positive for both tests. All 85 IB/Nt-negative samples were classified as negative with all CIAs. Of the 182 IB/Nt-positive samples, 25.3 to 61.5% were classified as equivocal and 6 to 64.8% were classified as positive with the CIAs. Wide variations in titers in international units per milliliter were observed. In our series, more than half of the women considered susceptible to RV based on CIA results tested positive for RV antibodies by IB/Nt. Our data suggest that (i) sensitivity of CIAs could be increased by considering equivocal results as positive and (ii) the definition of immunity to RV as the 10-IU/ml usual cutoff as well as the use of quantitative results for clinical decisions may warrant reconsideration. A better standardization of CIAs for RV IgG determination is needed.

Standardization of Assays That Detect Anti-Rubella Virus IgG Antibodies.

Rubella virus usually causes a mild infection in humans but can cause congenital rubella syndrome (CRS). Vaccination programs have significantly decreased primary rubella virus infection and CRS; however, vaccinated individuals usually have lower levels of rubella virus IgG than those with natural infections. Rubella virus IgG is quantified with enzyme immunoassays that have been calibrated against the World Health Organization (WHO) international standard and report results in international units per milliliter. It is recognized that the results reported by these assays are not standardized. This investigation into the reasons for the lack of standardization found that the current WHO international standard (RUB-1-94) fails by three key metrological principles. The standard is not a pure analyte but is composed of pooled human immunoglobulin. It was not calibrated by certified reference methods; rather, superseded tests were used. Finally, no measurement uncertainty estimations have been provided. There is an analytical and clinical consequence to the lack of standardization of rubella virus IgG assays, which leads to misinterpretation of results. The current approach to standardization of rubella virus IgG assays has not achieved the desired results. A new approach is required.

Rubella and pregnancy: diagnosis, management and outcomes.

Rubella is a mild viral disease that typically occurs in childhood. Rubella infection during pregnancy causes congenital rubella syndrome, including the classic triad of cataracts, cardiac abnormalities and sensorineural deafness. Highly effective vaccines have been developed since 1969, and vaccination campaigns have been established in many countries. Although there has been progress, the prevention and diagnosis of rubella remain problematic. This article reviews the implications and management of rubella during pregnancy.

[Rubella: a current issue?]. / La rubéole : une question d'actualité ?

Sporadic cases of rubella infection are reported each year in France due to insufficient vaccination coverage. Rubella virus is a very unstable enveloped RNA virus. For this reason, transportation and storage of samples collected for its detection require particular conditions. The genetic stability of rubella virus has allowed the development of very effective vaccines. During the recent rubella outbreaks in Algeria and Tunisia, an unusual high rate of encephalitis was reported. The role of the laboratory is crucial in the management of rubella infection during pregnancy. Rubella serological results must be interpreted with caution. Congenital rubella is a severe disease that should already be eliminated thanks to a very effective vaccine that has been developed. All women of childbearing age should be vaccinated. Rubella vaccination of an unknowingly pregnant woman is not an indication for abortion.

Evaluation of fully automated assays for the detection of Rubella IgM and IgG antibodies by the Elecsys(®) immunoassay system.

Screening for acute rubella infection in pregnancy is an important element of antenatal care. This study compared the sensitivity, specificity and reproducibility of two new, fully automated Elecsys(®) Rubella IgM and IgG immunoassays designed for the Elecsys 2010, Modular Analytics E170, COBAS e-411 and COBAS e-601 and e602 analytical platforms, with current assays using serum from patients with primary rubella infections, vaccinated patients, patients with potentially cross-reacting infections and on routine samples in clinical laboratories in France, Germany and Italy. Both assays showed good within-run and within-laboratory precision. A sensitivity of 79.8-96.0% was demonstrated for Elecsys IgM in primary, early acute infection, consistent with existing assays. In samples obtained from routine antenatal screening, the Elecsys Rubella IgM assay revealed high specificity (98.7-99.0%). A significantly (p<0.0001) lower reactivity was demonstrated in samples from previously infected patients where acute rubella infection was excluded, and the incidence of false positives in patients with potentially cross-reacting infections was lower with Elecsys Rubella IgM compared with other. The Elecsys Rubella IgG assay exhibited a relative sensitivity of 99.9-100.0% and specificity of 97.4-100.0% in samples from routine antenatal screening. The Elecsys Rubella IgM and IgG assays allow convenient, rapid and reliable determination of anti-rubella antibodies. Sensitivity, specificity and reproducibility were comparable with existing assay systems. Assay results were available in approximately half the time required for currently employed methods and the assays are compatible with widely used analytical platforms.

[Infections transmitted from the mother to the fetus: diagnostic issues and management of pregnancy]. / Infections materno-fœtales: difficultés diagnostiques et prise en charge maternelle.

Some infections are considered as feared risks during pregnancy. These infections may lead to severe damage of the fetus or the newborn depending on the infectious agent and the term of pregnancy where the infection occurred. Antenatal screening (in France it concerns toxoplasmosis, rubella, syphilis and hepatitis B) play an important role in prevention and management of vertically transmissible infections. However, biological diagnosis is also essential when maternal/neo-natal clinical symptoms or abnormal ultrasound findings are observed. In this article we chose to focus on rubella, varicella, syphilis, toxoplasmosis, hepatitis B and cytomegalovirus and parvovirus infections.

Re-evaluation of the VIDAS(®) cytomegalovirus (CMV) IgG avidity assay: determination of new cut-off values based on the study of kinetics of CMV-IgG maturation.

BACKGROUND: In case of cytomegalovirus (CMV) infection, differentiation between primary and non-primary CMV infection can be of major importance for the correct management of pregnant women or immunocompromised patients. Besides CMV-IgM and IgG, CMV-IgG avidity measurement is now commonly used to distinguish primary from non-primary infection. OBJECTIVE: To re-evaluate the performance of the VIDAS CMV-IgG avidity assay in comparison with 2 other techniques (Architect Abbott and Liaison DiaSorin) and to study the kinetics of CMV-IgG avidity maturation. STUDY DESIGN: A panel of 135 sequential samples collected from 31 patients with a proven primary infection (attested by very recent CMV-IgG seroconversion) was tested with VIDAS, Liaison and Architect CMV-IgG avidity assays. Moreover, 235 routinely collected samples, CMV-IgG and CMV-IgM positive, were analyzed with Liaison, VIDAS and an in-house CMV-IgG avidity assay. RESULTS AND CONCLUSIONS: The analysis of all the data allowed suggesting new VIDAS cut-off values of 0.40 for low avidity and 0.65 for high avidity, which significantly increase the test performance and enable better patient managements. Using these VIDAS new cut-off values, all of the 31 primary infections were correctly dated. Comparatively, 25 out of 31 were correctly dated with the Architect assay and 29 out of 31 with the Liaison assay. We also demonstrated that the VIDAS CMV-IgG avidity assay allows observing correctly the maturation of CMV-IgG avidity, which could be useful as an additional parameter for diagnosis of a recent CMV infection.

Prospective identification of congenital cytomegalovirus infection in newborns using real-time polymerase chain reaction assays in dried blood spots.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is a public health issue, and implementation of neonatal screening has been debated. Detection of CMV DNA by polymerase chain reaction (PCR) of dried blood spots (DBS) routinely collected for metabolic screening from all newborns has been proposed for congenital CMV infection screening. The goal of this study was to prospectively assess the performance of 2 CMV PCR assays of DBS for CMV neonatal screening in a selected population of neonates. METHODS: We studied prospective congenital CMV screening in a population of neonates either born with symptoms compatible with congenital CMV or born to mothers with a history of primary infection during pregnancy. For each neonate, 2 CMV PCR assays of DBS were blindly performed in parallel with a gold standard technique (ie, CMV PCR of a urine sample). RESULTS: Two hundred seventy-one neonates were studied, and CMV infection, defined by a positive urine sample in the first week of life, was confirmed in 64 (23.6%). Nineteen infected (29.7%) neonates were symptomatic, and 45 (70.3%) were asymptomatic. The ranges of sensitivity, specificity, positive predictive value, and negative predictive value for the 2 CMV PCR assays of DBS were 95.0%-100%; 98.1%-99.0%; 94.1%-96.9%, and 98.5%-100%, respectively. CONCLUSIONS: The sensitivity and specificity of both CMV PCR assays of DBS to identify congenital CMV were very high in this population of neonates with a high risk of sequelae. These new data should be considered in the ongoing debate on the appropriateness of the use of DBS as a sample to screen for congenital CMV infection.

Phylogenetic analysis of rubella viruses involved in congenital rubella infections in France between 1995 and 2009.

Rubella is an acute infectious disease that normally has a mild clinical course. However, infections during pregnancy, especially before week 12 of gestation (WG), can cause severe birth defects known as congenital rubella syndrome (CRS). The aim of this study was to perform genotyping and molecular characterization of rubella viruses involved in congenital infections in France over the past 15 years (1995 to 2009). Amniotic fluid (AF) specimens (n = 80) from pregnant women with congenital rubella infections (CRI) before week 20 of gestation, and a few other samples available from children/newborns with CRS (n = 26), were analyzed. The coding region of the rubella virus E1 gene was amplified directly from clinical specimens by reverse transcriptase PCR, and the resulting DNA fragments were sequenced. Sequences were assigned to genotypes by phylogenetic analysis with rubella virus reference sequences. Sufficient E1 gene sequences were obtained from 56 cases. Phylogenetic analysis of the sequences showed that at least five different genotypes (1E, 1G, 1B, 2B, and 1h) were present in France and were involved in congenital infections, with a strong predominance of genotype 1E (87%). This is one of the very few comprehensive studies of rubella viruses involved in CRI. The results indicated that over the past 15 years, multiple introductions of the dominant genotype E caused most of the CRI cases in France. A few sporadic cases were due to other genotypes (1B, 1G, 1h, 2B).

Harmful effect of adipose tissue on liver lesions in patients with alcoholic liver disease.

BACKGROUND & AIMS: Adipose tissue is an important source of cytokines. Excess weight is an independent risk factor for steatosis, acute alcoholic hepatitis (AAH), and cirrhosis in patients with alcoholic liver disease (ALD). In this study, we investigated the role of adipose tissue in human ALD. PATIENTS AND METHODS: Fifty patients with ALD underwent liver and abdominal subcutaneous adipose tissue biopsies and supplied blood samples for the investigation of cytokine gene expression and secretion, as well as liver histology. RESULTS: The levels of TNF-alpha and IL-10 in adipose tissue were higher in patients with AAH. IL-10 level in adipose tissue was also correlated with fibrosis score. TNF-alpha gene expression in adipose tissue was correlated with Maddrey score, blood C-reactive protein (CRP) concentration and liver IL-6 concentration. IL-6 production levels in the liver were higher in patients with AAH and correlated with AAH score, liver histological lesions, liver TNF-alpha concentration, Maddrey score, and blood CRP concentration. Plasma concentrations of soluble forms of TNF-receptor were correlated with inflammatory lesions in the liver, Maddrey score and fibrosis score. CONCLUSION: In patients with ALD, inflammation occurs not only in the liver, but also in the adipose tissue. Adipose tissue inflammation is correlated with the severity of pathological features in the liver. Our findings may account for the harmful interactions between body mass index, AAH, fibrosis, and cirrhosis in alcoholic patients.

Does hygiene counseling have an impact on the rate of CMV primary infection during pregnancy? Results of a 3-year prospective study in a French hospital.

BACKGROUND: Cytomegalovirus (CMV) is the most frequent cause of congenital viral infection in developed countries. OBJECTIVES: The objective of this study was to evaluate the impact of our prenatal CMV infection screening and counseling policy. STUDY DESIGN: Since 2005, all pregnant women in our obstetric center have been informed about CMV infection, and if they agree, given a serological test at around 12 weeks of gestation (WG). If this first test is negative, the women and their partners are given hygiene counseling on how to prevent CMV infection, and a second test is performed at around 36 WG. RESULTS: Among the 5312 women who had an unknown immune status, or were known to be seronegative when they had their first visit to our center for their current pregnancy, 97.4% agreed to CMV screening. Primary infection was detected in 11 women between 0 and 12 WG (0.42%), and seroconversion was diagnosed in five women between 12 and 36 WG (0.19%). CONCLUSIONS: These results suggest that if clear information is given on CMV infection during pregnancy, the rate of seroconversion is lower following counseling than before counseling.

Acute hepatitis E infection associated with a false-positive serology against Epstein-Barr virus.

Hepatitis E virus is a major cause of acute viral hepatitis. The diagnosis of acute viral hepatitis E is based essentially on antibodies and hepatitis E virus RNA. We describe herein a case of acute hepatitis E associated with a false-positive serology for Epstein-Barr virus (EBV). This case report suggests that anti-viral capsid antigen IgM must be interpreted with caution in acute E hepatitis. When positive, EBV RNA polymerase chain reaction can be useful as a false positivity of anti-viral capsid antigen IgM and can be misinterpreted as an acute infection. EBV false positivity was probably related to polyclonal stimulation of the immune system, favoured by hepatitis E.

Evaluation of different cytomegalovirus (CMV) DNA PCR protocols for analysis of dried blood spots from consecutive cases of neonates with congenital CMV infections.

Two protocols for the extraction of cytomegalovirus (CMV) DNA and two methods for the amplification of CMV DNA in dried blood spots were evaluated for the retrospective diagnosis of congenital CMV infection. During the period from 1996 to 2006, a urine screening program detected 76 congenitally infected neonates. Stored Guthrie cards with blood from 55 cases and 12 controls were tested. Two spots of dried blood were cut from each card and evaluated in two centers. CMV DNA was extracted from a whole single spot. Center 1 used phenol-chloroform extraction and ethanol precipitation followed by a conventional PCR. Center 2 used the NucliSens easyMAG automated DNA/RNA extraction platform (bioMérieux) followed by a real-time PCR. For evaluation of the extraction method, DNA extracted from each blood spot was evaluated by the amplification method used by the collaborating center. The sensitivities were 66% for center 1 and 73% for center 2. None of the controls were positive. A sensitivity as high as 82% could be obtained by combining the most sensitive extraction method (the phenol-chloroform procedure) with the most sensitive PCR method (real-time PCR). The detection rate was not influenced by the duration of storage of the spots. The sensitivity was higher with blood from congenitally infected cases due to a primary maternal CMV infection, regardless of the protocol used. However, the difference reached significance only for the least-sensitive protocol (P = 0.036).

Development of a rapid and convenient method for determination of rubella virus-specific immunoglobulin G avidity.

We describe here a rapid and semiautomated method for the determination of rubella virus immunoglobulin G (IgG) avidity with the VIDAS instrument. A total of 153 serum samples from persons with naturally acquired rubella virus infections (n = 98), from vaccinated persons (n = 44), and from patients with autoantibodies (n = 11) were included in this study. The rubella virus-specific IgG avidity assay we developed for the VIDAS instrument was evaluated by comparison with an in-house method. Results obtained with the VIDAS instrument allow considering this method valuable to help confirm or exclude acute primary infection or recent vaccination.

Evaluation of cytomegalovirus (CMV) DNA quantification in dried blood spots: retrospective study of CMV congenital infection.

We compared two protocols for extracting DNA from dried blood spots for cytomegalovirus (CMV) DNA detection and quantification by real-time PCR. Both extraction methods were reliable for the retrospective diagnosis of CMV congenital infection. Quantification of CMV DNA was valuable after normalization of viral loads with albumin gene PCR amplification results.

Usefulness of specific IgG avidity for diagnosis of hepatitis A infection.

AIM: Diagnosis of acute hepatitis A virus (HAV) infection is classically based on the detection of HAV-IgM. Nevertheless, HAV-IgM can be positive for patients with polyclonal stimulation of their immune system (i.e. immune reactivation). To improve the diagnostic yield, an avidity test for HAV-IgG antibodies was developed and tested. METHODS: Avidity tests were performed in 128 sera: 11 selected samples from patients with past infection, 15 acute hepatitis A, 10 vaccinated subjects and 4 patients with immune reactivation as well as 84 HAV-IgM positive unselected sera, provided by routine laboratories. RESULTS: Patients with past infection had avidities over 70%, whereas avidities in patients with acute hepatitis A were below 50% during the first month following the onset of symptoms. As expected, patients with immune reactivation had avidities over 70% consistent with past infection. The results obtained for the 84 unselected sera allowed reconsidering the diagnosis of acute hepatitis A for nearly a third of patients. CONCLUSION: This test could improve the diagnosis of acute hepatitis A infection, particularly in elderly patients.