Shinya Tairaku

Prospective Study of Congenital Toxoplasmosis Screening with Use of IgG Avidity and Multiplex Nested PCR Methods

ABSTRACT Acute infection with Toxoplasma gondii during pregnancy can cause congenital toxoplasmosis. The aim of this study was to evaluate whether screening with the use of IgG avidity and multiplex nested PCR methods was effective to detect a high-risk pregnancy. In a prospective study, serum T. gondii IgG avidity was measured in consecutive 146 pregnant women testing positive for T. gondii antibody and either positive or equivocal for IgM. Multiplex nested PCR for T. gondii DNA on amniotic fluid, maternal blood, and umbilical cord blood were performed with informed consent. A total of 51 (34.9%) women presented with low IgG avidity (<30%), 15 (10.3%) presented with borderline avidity (30 to 35%), and 80 (54.8%) presented with high avidity (>35%) indices. Amniotic fluid obtained at amniocentesis or birth yielded positive PCR results in nine women with low IgG avidity indices. Of these nine women, three had congenital toxoplasmosis. None of women with high or border line IgG avidity indices had a positive PCR result in the amniotic fluid or congenital toxoplasmosis. No congenital toxoplasmosis was detected in women whose amniotic fluids yielded negative PCR results. Ingestion of raw or undercooked meat was found to be the main risk factor for acute T. gondii infection. Congenital toxoplasmosis screening with a combination of IgG avidity in the maternal blood and multiplex nested PCR in the amniotic fluid was useful for detecting a high risk pregnancy and diagnosing congenital toxoplasmosis.

Fetal cell-free DNA fraction in maternal plasma is affected by fetal trisomy.

The purpose of this noninvasive prenatal testing (NIPT) study was to compare the fetal fraction of singleton gestations by gestational age, maternal characteristics and chromosome-specific aneuploidies as indicated by z-scores. This study was a multicenter prospective cohort study. Test data were collected from women who underwent NIPT by the massively parallel sequencing method. We used sequencing-based fetal fraction calculations in which we estimated fetal DNA fraction by simply counting the number of reads aligned within specific autosomal regions and applying a weighting scheme derived from a multivariate model. Relationships between fetal fractions and gestational age, maternal weight and height, and z-scores for chromosomes 21, 18 and 13 were assessed. A total of 7740 pregnant women enrolled in the study, of which 6993 met the study criteria. As expected, fetal fraction was inversely correlated with maternal weight (P<0.001). The median fetal fraction of samples with euploid result (n=6850) and trisomy 21 (n=70) were 13.7% and 13.6%, respectively. In contrast, the median fetal fraction values for samples with trisomies 18 (n=35) and 13 (n=9) were 11.0% and 8.0%, respectively. The fetal fraction of samples with trisomy 21 NIPT result is comparable to that of samples with euploid result. However, the fetal fractions of samples with trisomies 13 and 18 are significantly lower compared with that of euploid result. We conclude that it may make detecting these two trisomies more challenging.

A novel PIGN mutation and prenatal diagnosis of inherited glycosylphosphatidylinositol deficiency.

Glycosylphosphatidylinositol (GPI) anchors tether proteins to the extracellular face of eukaryotic plasma membranes. Defects in the human GPI anchor biosynthetic pathway cause inherited GPI deficiencies (IGDs) characterized by multiple congenital anomalies: dysmorphic faces, developmental delay, hypotonia, and epilepsy. We report the case of a 6‐year‐old boy with severe psychomotor developmental delay, epilepsy, and decreased granulocyte surface expression of GPI‐anchored protein that suggested autosomal recessive GPI deficiency. The case underwent target exome sequencing to screen for IGDs. Target exome sequencing of the proband identified an apparently homozygous c.808T > C (p.Ser270Pro) mutation in PIGN, a gene involved in the GPI anchor biosynthetic pathway. As his parents were expecting another child, genetic carrier screening was conducted for the parents. Direct sequencing of the parents identified a heterozygous c.808T > C PIGN mutation in the father but none in the mother. To identify the mothers mutation, we performed semi‐quantitative real‐time PCR of the PIGN exons and long PCR, identifying a microdeletion in PIGN (del exons 2–14). The proband had inherited this microdeletion from his mother. Prenatal diagnosis of the fetus revealed that it was a heterozygous carrier of the mothers pathogenic allele. Here, we report a sporadic case of inherited GPI deficiency with a PIGN mutation and the first case of prenatal diagnosis for GPI deficiency.

Awareness of and knowledge about mother‐to‐child infections in Japanese pregnant women

To reduce the incidence of infants with congenital infections, women should be aware of and know prevention measures against maternal infection with mother‐to‐child infections during pregnancy. Our objective was to assess the awareness of and knowledge about mother‐to‐child infections in Japanese pregnant women. A survey of 343 Japanese pregnant women was completed. Awareness of 13 pathogens capable of mother‐to‐child transmission was surveyed. Knowledge about the transmission route, the most susceptible time of infection that may cause severe fetal disease during pregnancy, and methods to prevent maternal infection were investigated for four major pathogens (cytomegalovirus, rubella virus, Toxoplasma gondii, and parvovirus B19) and results were compared between these pathogens. The proportion of women aware of pathogens concerning TORCH syndrome was the following: rubella virus 76%, Treponema pallidum 69%, Toxoplasma gondii 58%, parvovirus B19 28%, herpes simplex virus 27%, and cytomegalovirus 18%. Only 8% knew how cytomegalovirus is transmitted, and only 12% knew how parvovirus B19 is transmitted; both were significantly lower than those who knew transmission routes for rubella virus or Toxoplasma gondii. The proportion of women who knew the most susceptible time for severe fetal infection by maternal acquisition of cytomegalovirus, Toxoplasma gondii, or parvovirus B19 was significantly lower than that for rubella virus. The vast majority of surveyed women were not aware of methods to prevent maternal infection with cytomegalovirus or parvovirus B19. In conclusion, current awareness of and knowledge about cytomegalovirus and parvovirus B19 infection are low in Japanese pregnant women.

Low IgG avidity and ultrasound fetal abnormality predict congenital cytomegalovirus infection

Cytomegalovirus (CMV) causes congenital infection with high mortality and morbidity rates in affected neonates. The aim of this study was to assess whether prenatal clinical or laboratory findings in pregnant women who had high risks for primary CMV infection predicted the presence of congenital infection. Fifty pregnant women who had serum CMV IgG and positive or borderline tests for serum CMV IgM were included in this prospective study. Serum IgG avidity was measured, and PCR was conducted for CMV DNA in maternal serum, urine, and uterine cervical secretion. All neonates underwent PCR testing for CMV DNA in the urine for the presence of congenital infection. Risk factors were compared between congenital infection group and group without congenital infection. As a result, nine neonates (18%) were diagnosed as having congenital infection. The frequencies of ultrasound fetal abnormality and positive test for CMV DNA in cervical secretion, CMV IgM titer and IgM/IgG ratio in the congenital infection group were significantly higher than those in the group without congenital infection. Conversely, IgG avidity index in the congenital infection group was significantly lower than that in the group without congenital infection. By multivariate logistic regression analyses, IgG avidity index (Odds ratio 0.91, 95% CI: 0.83–0.99) and ultrasound fetal abnormality (291.22, 2.72–31125.05), were selected independently as significant signs predictive of congenital CMV infection. Among pregnant women with positive or borderline tests for CMV IgM, when they have findings of low serum CMV IgG avidity or ultrasound fetal abnormality, the probability of congenital CMV infection may increase. J. Med. Virol. 84:1928–1933, 2012.

Rapid increase in the serum Cytomegalovirus IgG avidity index in women with a congenitally infected fetus

BACKGROUND Human Cytomegalovirus (CMV) is the virus most frequently responsible for severe diseases of the fetus and newborn. The reported intrauterine transmission rate of CMV following primary maternal infection is approximately 40%. Invasive techniques are needed for the prenatal diagnosis of congenital CMV infection. OBJECTIVES The aim of this study was to evaluate whether the rapidity of change in the CMV IgG avidity index (AI) is associated with the presence of congenital CMV infection among mothers with suspected primary CMV infection. STUDY DESIGN The serum CMV IgG AI was repeatedly measured in 17 pregnant women with positive or borderline test results for CMV IgM together with an initial IgG AI value of <40%. Their neonates underwent polymerase chain reaction analyses for the presence of CMV DNA in the urine. The rapidity of change in the IgG AI per 4 weeks was defined as the ΔAI (%). The ΔAI of women with congenital CMV infection was compared with that of women with no infection. RESULTS The ΔAI of nine mothers with congenital CMV infection (median,15.7%; range,7.8-42.8%) was significantly higher than that of eight mothers with no infection (median, 6.5%, range, 2.0-8.8%; p<0.001). The incidences of congenital CMV infection were 100.0%, 16.7%, and 0.0% among mothers with a ΔAI of >10, 5-10, and <5%, respectively. CONCLUSIONS Measurement of the ΔAI in pregnant women might be useful for estimating the risk of mother-to-neonate CMV transmission.

The IgG avidity value for the prediction of congenital cytomegalovirus infection in a prospective cohort study.

Abstract Background: Cytomegalovirus (CMV) causes congenital infection with high mortality and morbidity rates in affected neonates. Objectives: To evaluate the maternal IgG avidity value for the prediction of congenital CMV infection. Study design: The serum IgG avidity in all mothers was measured, and the urine of their neonates was assessed for CMV DNA in a prospective cohort study. Results: Of 759 women with a positive test for CMV IgG, 14 had congenital CMV infection. CMV IgG avidity indices in the congenital infection group (median 35.1%) were significantly lower than those in the non-congenital infection group (70.4%). A cutoff value of <40% IgG avidity index with 96.1% specificity and 64.3% sensitivity for congenital infection was determined by receiver operating characteristic curve analyses. The highest sensitivity (88.9%), 96.2% specificity, 27.6% positive predictive value, 99.8% negative predictive value, and 96.1% accuracy were found when IgG avidity was measured in <28 weeks of gestation. Conclusion: The IgG avidity measurement with a cutoff value of <40% IgG avidity index might be helpful in predicting congenital CMV infection, especially in <28 weeks of gestation.

Universal Screening With Use of Immunoglobulin G Avidity for Congenital Cytomegalovirus Infection

Background The aim of this prospective cohort study was to evaluate the efficacy of maternal screening for congenital cytomegalovirus infection (CCI) using cytomegalovirus (CMV) immunoglobulin G (IgG) and the IgG avidity index (AI). Methods Pregnant women underwent screening of CMV IgG and AI measurements. IgG-negative women underwent remeasurement of IgG after educational intervention. Women with an AI ≤45% received further examinations, including measurement of CMV IgM. All newborns received polymerase chain reaction analyses of the urine, and CCI was diagnosed by the detection of CMV-DNA in the urine. Primary infection was defined as an AI <35% and/or positive IgM (>1.20 index). Serum samples from women with an AI >45% were stored, and the IgM levels were measured after delivery. The efficacy of AI and IgM for CCI screening was compared. Results A total of 1562 (71.2%) women tested positive for IgG. In this study, 10 newborns with CCI were detected. The presence of infection in 3 newborns from mothers with primary infection was predicted by screening of IgG and AI <35%. However, infection in 7 newborns from women with nonprimary infection could not be predicted by screening of CMV IgG, AI <35%, or IgM. The application of an AI <35% for CCI screening yielded 22.2% sensitivity, 95.0% specificity, 2.5% positive predictive value, and 99.5% negative predictive value and was similar to that of IgM (11.1% sensitivity, 93.2% specificity, 0.9% positive predictive value, and 92.7% negative predictive value). Conclusions Maternal screening using CMV IgG and AI can identify pregnancies with CCI from primary infection, but overlooks a number of those from nonprimary infection.

Nationwide survey of mother-to-child infections in Japan.

OBJECTIVES The aim of this survey study was to evaluate a state of mother-to-child infections in Japan. METHODS A nationwide survey on 2714 obstetric facilities where regular maternity checkups were carried out was conducted. A primary questionnaire assessed numbers of pregnancies including induced abortion, spontaneous abortion, still-birth as well as live-birth, which were affected by congenital infections of 6 pathogens during a year of 2011. The secondary questionnaire assessed clinical information, diagnostic modality, and the outcome for each case. The clinical features and diagnostic problems were evaluated. RESULTS The high reply rates for the primary (73.7%) and the secondary questionnaire (100%) were achieved. The presence of congenital infections for 34 cases with cytomegalovirus (CMV), 1 with Toxoplasma gondii, 4 with rubella virus, 5 with Treponema pallidum, 8 with herpes simplex virus, and 69 with parvovirus B19 was confirmed after questionnaire assessment. The incidence of fetal demise among pregnancies with congenital parvovirus B19 infection was up to 71.0%. Eleven mothers with hydrops fetalis received prenatal fetal therapies involving fetal blood transfusion and immunoglobulin administration, whereas only three pregnancies (27.3%) ended in live-births. CONCLUSIONS This survey study for the first time revealed the annual frequency of pregnancies with mother-to-child infections of 6 pathogens in Japan. The results involve important information and are helpful for clinical practitioners. The majority of neonates with congenital infection of CMV or T. gondii might be undiagnosed in obstetric facilities.

Prediction of Congenital Cytomegalovirus Infection in High-Risk Pregnant Women

Background. This prospective study aimed to determine maternal clinical, laboratory, and ultrasound findings that effectively predict the occurrence of congenital cytomegalovirus (CMV) infection (CCI) in high-risk pregnant women. Methods. Three hundred CMV immunoglobulin (Ig) M–positive pregnant women were enrolled. The maternal clinical and laboratory findings, including serum CMV IgM and IgG; IgG avidity index (AI); antigenemia assay (C7-HRP); polymerase chain reaction (PCR) for the detection of CMV-DNA in the maternal serum, urine, and uterine cervical secretion; and prenatal ultrasound findings, were evaluated. To determine predictive factors for the occurrence of CCI, logistic regression analyses were performed. Results. In 22 of the 300 women, CCI was confirmed using PCR for CMV-DNA in newborn urine. Univariate analyses demonstrated that the presence of maternal flu-like symptoms, presence of ultrasound fetal abnormalities, serum titers of CMV IgM, positive results for C7-HRP, CMV IgG AI <40%, and positive PCR results in the uterine cervical secretion were statistically associated with the occurrence of CCI. Multivariable analysis revealed that the presence of ultrasound fetal abnormalities (odds ratio [OR], 31.9; 95% confidence interval [CI], 8.5–120.3; P < .001) and positive PCR results in the uterine cervical secretion (OR, 16.4; 95% CI, 5.0–54.1; P < .001) were independent predictive factors of CCI in CMV IgM-positive women. Conclusions. This is the first prospective cohort study to suggest that the presence of CMV-DNA in the maternal uterine cervical secretion and ultrasound fetal abnormalities are predictive of the occurrence of congenital CMV infection in high-risk pregnant women.