Serological investigation of BK papovavirus infection in pregnant women and their offspring.

Paired sera from 150 pregnant women and 387 umbilical cord sera were tested for BK virus (BKV) antibodies. The hemagglutination inhibition, neutralization, and indirect immunofluorescence tests were employed for the detection of antibodies. Treatment of serum with anti-gamma Fc and tests of immunoglobulin M (IgM) fractions for antibodies were utilized as required to detect and validate the presence of virus-specific IgM. The BKV antibody prevalence in the sera collected at the time of the first prenatal visit was 75% by hemagglutination inhibition and 91% by neutralization tests. A total of 95% of the women had antibodies by at least one of the three serological tests. Five of 100 women with normal pregnancies exhibited BKV activity during pregnancy as evidenced by a greater than fourfold rise in BKV hemagglutination inhibition antibody titers and acquisition of BKV-specific IgM. The antibody rise occurred in the younger women and appeared to be a result of reactivation of the virus rather than of primary infection. Two instances of possible recent BKV infections were identified. BKV-specific IgM was not detected in any of the 387 umbilical cord sera which included three specimens from infants born to mothers with definite or probable BKV activity during pregnancy and 50 specimens with IgM levels of > 20 mg/100 ml. The results indicate that few women in the child-bearing age are nonimmune to BKV and that, although reactivation of infection occurs in pregnancy, congenital transmission of the virus either does not occur or is rare.     

Congenital cytomegalovirus infection in Korean population with very high prevalence of maternal immunity.

In order to asses congenital cytomegalovirus (CMV) infection in Korea, five hundred and seventy five pregnant women (mean age 29.5 +/- 3.8 yrs., mean gestational age at test 37.5 +/- 6.7 weeks) visiting the prenatal clinic at Severance Hospital, Seoul, Korea were studied. CMV IgG antibody was present in 96% (552/575) and IgM antibody was present in 0.7% (4/575) of the pregnant women by the third trimester. Four of 445 cord sera were positive for CMV IgM antibody (0.9%). Urine samples from 514 newborns were tested for the evaluation of congenital CMV infection. Six (1.2%) of 514 newborns excreted CMV in their urine. All the congenitally infected infants had subclinical involvement at birth and during the 12 months of the follow-up period. These results indicate that Korean pregnant women were highly immunized against CMV by the third trimester. Furthermore this study suggests that the rate of congenital CMV infection is relatively as high as rates previously reported from other countries, although there is a very high prevalence of maternal immunity. The incidence of maternal primary infection during pregnancy seems to be rare and therefore most congenital infections in Korea might be following by maternal reactivation or reinfection.     

Investigation on the Maternal-Infantile Infection with Human Parvovirus B19

With the investigations on pregnant women and newbornsinfected withToxoplasma, rubella virus, cytomegalovirus,herpes simplex virus (TORCH), it was found that humanparvovirus B19 (B19 virus), which belongs to the familyParvoviridae and the genus Erythrovir…     

Comparative evaluation of two commercial enzyme immunoassays for serodiagnosis of human parvovirus B19 infection

The present study describes the performance of two commercial enzyme immunoassays (EIAs) employing recombinant capsid proteins derived from baculovirus or from yeast for diagnosis of human parvovirus B19 (B19) infection. At first, 450 sera from routine daily practice submitted consecutively for B19 antibody testing during a 2-week period in March 2006 were tested. Eighty percent of the routine sera were from pregnant women. There was a high degree of accordance between the two assay systems in detection of B19 IgG antibodies (98.9%) and B19 IgM antibodies (98.7%). Specific antibody concentrations of serum specimens with discordant test results (n=11) were within or close to the equivocal range of the respective assay. Subsequently, specificity and sensitivity of the IgM EIAs were assessed in detail by testing 160 sera collected from patients with a defined disease state. Specificity ranged between 94.2 and 98.5% in patients (n=70) with other acute infections or autoimmune diseases. In sera from pregnant women (n=30) and children (n=30) with acute B19 infection, both assays were 100% sensitive. Whereas sensitivity varied from 63.0 to 70.0% in pregnant women (n=30) investigated 8-12 weeks after onset of disease. According to our evaluation the diagnostic performance of the two assay systems appears to be substantially equivalent. Fetal hydrops is sometimes a late complication of gestational B19 infection and maternal B19 IgM antibodies may already have declined to undetectable levels at the time of clinical diagnosis. A negative B19 IgM test during pregnancy should therefore be interpreted with caution.     

Assessment of the diagnostic value of RT-PCR on amniotic fluid for prenatal diagnosis of congenital rubella infection

AIM OF THE STUDY: To assess the diagnostic value of RT-PCR on amniotic fluid (AF) for prenatal diagnosis of congenital rubella infection. MATERIAL AND METHODS: RT-PCR on AF was compared to specific IgM antibody detection in foetuses and/or newborns in 45 pregnant women with confirmed primary infection. RESULTS: specificity of RT-PCR was 100% and sensitivity ranged between 83 and 95%. CONCLUSION: RT PCR may be considered as a valuable tool for prenatal diagnosis of foetal rubella infection.     

Susceptibility of pregnant women to toxoplasma infection--potential benefits for newborn screening

Congenital toxoplasmosis (CT) arises as a result of new acquisition of Toxoplasma infection by a susceptible woman during pregnancy. Early detection of CT through neonatal screening programmes could optimize management and improve infant outcome. This study sought to estimate the prevalence of Toxoplasma susceptibility in pregnant women. As detection of Toxoplasma antibodies in neonatal blood reflects maternal exposure history, maternal antibody seroprevalence was determined using anonymized residual blood from newborn screening cards. A total of 20,252 cards were tested in 1 year. 4,991 (24.6%) cards tested positive for Toxoplasma antibody. Results were stratified by county. Toxoplasma antibody seroprevalence rates of 25% indicated that Toxoplasma infection is common in Ireland and that up to 75% of women remain susceptible to primary infection during pregnancy. This study aimed to a) determine the seroprevalence of Toxoplasma antibody in pregnant women, and hence b) estimate the risk for acquisition of primary toxoplasmosis in pregnancy in order to support an application to fund a pilot newborn screening programme.     

Use of recombinant glycoprotein antigens gB and gH for diagnosis of primary human cytomegalovirus infection during pregnancy

The major risk factor for intrauterine transmission of human cytomegalovirus (HCMV) is a primary infection during pregnancy. The neutralizing antibody response appeared after an average of 13 weeks after seroconversion and therefore the absence of neutralizing titers in HCMV IgG positive pregnant women is a reliable marker for primary infection. Determination of neutralizing antibody, however, is time-consuming and labor-intensive. For this reason an immunoblot assay for detection of neutralizing antibodies was developed based on the use of recombinant antigens representing neutralizing epitopes of glycoproteins (gp) gB (gpUL55) and gH (gpUL75) of HCMV. In this study, 93.6% of sera of pregnant women with prior infection recognized the gp-specific epitopes corresponding to a nonresponder rate of 6.4% relative to the neutralizing antibody. In primary infection the gp-response in general coincided with the appearance of neutralizing antibody. Intriguingly, lack of HCMV gB-specific antibodies was correlated with a lower risk of intrauterine fetal infection (P < 0.05).     

Differentiation between acute primary and recurrent human cytomegalovirus infection in pregnancy,using a microneutralization assay

Acute primary human cytomegalovirus (HCMV) infection in pregnancy, the major cause of congenital symptomatic infection, is often difficult to differentiate from recurrent infection, which presents a considerably smaller risk to the fetus. Therefore, the diagnosis of primary infection in pregnancy is very important, especially if seroconversion is not documented and follow-up sera with declining IgM-titers are not available. To investigate the value of the neutralizing antibody response against HCMV in differentiating acute primary from recurrent and past infection, well-characterized sera from pregnant women were examined. Employing a microneutralization assay, it was found that neutralizing antibodies first appeared approximately 15 weeks after acute infection. However, serum samples of pregnant women with recurrent or past infection consistently displayed neutralizing activity. In conclusion, the neutralization assay can be used as a reliable method for discriminating acute primary from previous or recurrent infection in a single serum sample. J. Med. Virol. 56:351–358, 1998 . © 1998 Wiley-Liss, Inc.     

Toxoplasma gondii antibodies in HIV and non-HIV infected Thai pregnant women

Serological evidence for Toxoplasma gondii infection in Thai pregnant women was investigated. One thousand six hundred and sixty-nine blood specimens were collected from 838 HIV-seropositive and 831 HIV-seronegative pregnant women attending the antenatal-care clinic at Siriraj Hospital, Bangkok, Thailand, during a two-year period. Toxoplasma IgG antibody was detected, using a solid-phase enzyme-linked immunosorbent assay in which the membrane protein p-30 was the predominant antigen. IgG positive sera were subsequently examined for IgM antibody by the capture antibody enzyme immunoassay. The IgG antibody was found in 450 (53.7%) HIV seropositive women and 44 (5.3%) non-HIV infected women, with a statistically significant difference (p < 0.0001). Three of the 450 HIV-seropositive and 2 of the 44 HIV-seronegative sera with IgG antibody were positive for IgM antibody against T. gondii. This result suggested that HIV seropositive pregnant women had a higher risk of Toxoplasma infection with increase exposure to their offspring.     

Frequency of human cytomegalovirus-specific T cells during pregnancy determined by intracellular cytokine staining

The characteristics of cytomegalovirus (CMV)-specific T-cell immunity was investigated in pregnant women with primary, latent, or reactivated CMV infection, and in a comparative group of non-pregnant women. Forty-six pregnant and 8 non-pregnant women were examined based on the presence of serum antibody activity against CMV and viral excretion in urine. The frequency of CMV-specific CD4(+) T cells in peripheral blood lymphocytes was determined by staining for intracellular cytokines, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha. There was no change in the frequencies of CMV-specific CD4(+) T cells in CMV-seropositive normal non-pregnant and pregnant women at any gestation. However, the frequency of CMV-specific CD4(+) T cells in pregnant women associated with CMV reactivation or reinfection was significantly higher than in CMV-seropositive normal pregnant and non-pregnant women. There were no CMV transmissions to the infants of all these women. These CMV-specific T cells responses in pregnant women may contribute some to block the intrauterine CMV infection in their infants.     

Low cytomegalovirus sero-prevalence in Irish pregnant women

The aim of this study was to determine the sero-prevalence of cytomegalovirus (CMV) IgG antibody in pregnant women in Ireland and assess individual risk factors for prior acquisition of CMV. In 2002, sera from 1047 pregnant women were tested by enzyme immunoassay for CMV IgG. Age and nationality were recorded for each patient. Among Irish-born women the following additional factors were also recorded: socio-economic status, number of children and occupational exposure to children. Only 30.4% (204/670) of Irish women were CMV antibody positive compared to 89.7% (322/359) of non-Irish women (p < 0.001). Non-Irish women were mostly from Sub-Saharan Africa, Eastern Europe and Asia. Lower socio-economic group and increasing number of children were significant independent predictors of CMV sero-positivity among Irish pregnant women (p < 0.05). Irish pregnant women have one of the lowest reported CMV sero-prevalence rates worldwide, indicating low circulation of CMV within the community. However, up to 70% of Irish women are susceptible to a primary infection during pregnancy.     

Pregnancy IFN-gamma responses to foetal alloantigens are altered by maternal allergy and gravidity status

Background: During pregnancy, variations in maternal–foetal cellular interactions may influence immune programming. This study was carried out to determine if maternal responses to foetal alloantigens are altered by maternal allergic disease and/or previous pregnancies. Methods: For this cohort study, peripheral blood was collected from allergic (n = 69) and nonallergic (n = 63) pregnant women at 20, 30, 36‐week gestation and 6‐week postpartum (pp). Cord blood was collected at delivery. Mixed lymphocyte reactions were used to measure maternal cytokine responses [interleukin‐6 (IL‐6), IL‐10, IL‐13 and (interferon‐γ) IFN‐γ] at each time point towards foetal mononuclear cells. Results: Maternal cytokine responses during pregnancy (20, 30 and 36 weeks) were suppressed compared to the responses at 6‐week pp. The ratio of maternal IFN‐γ/IL‐13 and IFN‐γ/IL‐10 responses were lower during pregnancy. Allergic mothers had lower IFN‐γ responses at each time‐point during pregnancy with the greatest difference in responses observed at 36‐week gestation. When allergic and nonallergic women were further stratified by gravidity group, IFN‐γ responses of allergic multigravid mothers were significantly lower than nonallergic multigravid mothers during pregnancy. Conclusions: During normal pregnancy, peripheral T‐cell cytokine responses to foetal alloantigens may be altered by both allergic status of the mother and previous pregnancies. These factors could influence the cytokine milieu experienced by the foetus and will be further explored in the development of allergic disease during early life.     

Measurement of BK papovavirus IgG and IgM by radioimmunoassay (RIA)

Current techniques for the measurement of BK papovavirus (BKV) specific IgM include sucrose density gradient centrifugation followed by hemagglutination inhibition (HAI) or indirect immunofluorescent (IF) staining of BKV infected cells using a fluorescein conjugated anti-human IgM antibody. These techniques are cumbersome and labor intensive and do not lend themselves to testing large numbers of sera. A solid phase radioimmunoassay (RIA) was developed to facilitate the measurement of BKV IgG and IgM in large numbers of sera. Solid phase antigen was prepared by adsorbing CsCl purified BKV antigen to polyvinyl chloride microtiter plates. Following reaction with serum, bound immunoglobulin was detected with iodinated goat anti-human IgG or IgM. RIA for the measurement of BKV IgG was sensitive with titers approaching 10⁻⁶. Determination of IgG titers by RIA and HAI showed good agreement (P < 0.01, correlation coefficient = 0.74). Measurement of BKV IgM was not affected by the presence of BKV IgG as evidenced by sucrose density gradient fractionation of IgM positive sera, removal of IgG by treatment with S. aureus protein A, and addition of BKV IgG to BKV IgM. Rheumatoid factor (RF) gave false positive IgM titers in the presence of BKV IgG when RF titers were ≥ 1:640 by latex agglutination testing and BKV IgG levels exceed 1:256 by HAI. False positives due to RF could be eliminated by treatment of sera with sheep anti—human IgG antisera. RIA for BKV IgM was specific as sera containing JCV-, cytomegalovirus (CMV)-, rubella-, or hepatitis B core antibody (anti HBc)—IgM were negative by RIA. RIA detected BKV IgM in several sera from renal dialysis or allograft palienls with titers ranging from 1:400 to 1:128,000 and demonstrated that BKV IgM persisted in sera of renal allograft patients for as long as 343 days post transplantation.     

江苏地区中孕期妇女巨细胞病毒感染率及感染状态与不良妊娠结局的关系

目的江苏省中孕期妇女的巨细胞病毒（cytomegalovirus,CMV）血清流行率,探讨母孕期感染状态与不良妊娠结局的相关性。方法根据2002-2004年江苏省12个市县17661例孕妇的新生儿结局,527例有不良妊娠结局的孕妇纳入病例组,同时随机选取496例正常妊娠结局的孕妇为正常对照。检测孕妇妊娠15～20周外周血CMV IgG、IgM和IgG亲合力指数（avidity index,AI）。结果1023例孕妇的CMV IgG阳性率为98.7％,其中病例组和对照组孕妇阳性率分别为99.4％和98.0％（P=0.039）。病例组孕妇活动感染率,即CMV IgG＋／IgM＋,明显高于正常对照组（3.8％vs.1.6％,P=0.033）。CMV IgG AI检测结果显示,对照组孕妇AI均大于30%,说明无原发感染,而病例组孕妇5例（0.9％）AI〈30％,提示原发感染（P=O.084）,这5例母亲的新生儿均出现不良妊娠结局,包括新生儿死亡、头颅畸形和化脓性脑膜炎各1例,生长发育迟缓2例。多因素回归分析表明,母孕期CMV活动性感染是不良妊娠结局的独立危险因素（aOR 8.65,95％CI 1.85～40.41,P=0.006）。此外,母亲低学历和有既往不良妊娠史亦增加妊娠不良结局的发生风险。结论CMV感染在江苏地区孕妇人群中普遍存在。尽管仅少部分孕妇在孕期发生活动性感染,但仍是造成妊娠不良结局的独立危险因素。因此,应监测孕妇CMV感染状态并正确进行胎儿或新生儿感染风险的评估。     

Dynamics of pregnancy-associated polyomavirus urinary excretion: a prospective longitudinal study

Asymptomatic polyomaviruria of pregnancy has been documented in point prevalence studies, but little attention has been given to the dynamics of polyomavirus excretion during pregnancy because of its benign course. We tested the hypothesis that the frequency and/or magnitude of polyomavirus excretion would increase as pregnancy progresses. Urine specimens were obtained prospectively from 179 healthy women during uncomplicated pregnancies and 37 healthy non‐pregnant women. Real‐time polymerase chain reaction was used to determine BK virus (BKV) and JC virus (JCV) viral loads in urine, blood, and rectal and vaginal swabs collected during routine obstetric and gynecologic clinic visits. Asymptomatic urinary shedding of BKV and/or JCV was observed in 384 (48.0%) of 800 specimens from 100 (55.8%) pregnant women. BKV excretion was more common in pregnant than non‐pregnant women (41.3% vs. 13.5%, P = 0.0026). The frequency of JCV excretion was no different in pregnant compared to non‐pregnant women. The frequency and magnitude of polyomavirus shedding did not vary with gestational age. Post‐partum shedding of BKV, but not JCV, rapidly decreased to undetectable levels. Pregnancy‐associated BKV excretion begins early in pregnancy and terminates rapidly post‐partum. Neither the frequency nor magnitude of BKV or JCV shedding increased with pregnancy progression. Further study into the host factors that regulate pregnancy‐associated BKV excretion may allow identification of the host factors that predict susceptibility to BKV‐associated diseases in immune compromised patients. J. Med. Virol. 84: 1312–1322, 2012. © 2012 Wiley Periodicals, Inc.     

Incidence and prevalence of toxoplasmosis in Indian pregnant women: a prospective study

PROBLEM: Toxoplasmosis is a major cause of congenitally acquired infections causing high degree of morbidity and mortality in the newborns. METHODS OF STUDY: IgG avidity method was used to distinguish the recent and more than 4 months old infection in a prospective cohort study for the first time in India. One hundred and eighty pregnant women presented in their first 4 months of pregnancy were included in this study. Their sera were tested for anti-Toxoplasma gondii antibodies using direct agglutination test, immunoglobulin (Ig)G and IgM-enzyme-linked immunosorbent assay, IgM-immunosorbent agglutination assay and VIDAS-IgG avidity. RESULTS: Overall IgG seroprevalence rate of toxoplasmosis was 45%. Only seven women (3.3%) were found to have IgM antibodies and only two of these showed low IgG avidity indicating recent infection of 相似文献   

Kinetics of rubella-specific IgM antibody response in postnatal rubella infection

The serological diagnosis of primary postnatal rubella infection is based on detection of rubella-virus-specific IgM antibody or a four-fold rise in rubella-specific IgG antibody. Although there are several different methods of enzyme immunoassays that are commercially available, the cost benefit evaluation makes them impractical for use in developing countries. For this reason, we have standardized the measurement of rubella IgM antibody by HAI following serum fractionation by ion-exchange chromatography. The sera samples obtained from pregnant women infected with rubella virus at different times during gestation were fractionated and tested by HAI. Seven out of nine sera collected within the first two days after onset of rash showed detectable levels of rubella IgM antibody. All 57 sera collected between 3 and 30 days after the onset of rash contained rubella IgM antibody. After 30 days, only 1 of 5, or 20%, of sera contained IgM antibody. The HAI testing method was rapid and specific and the cost was not prohibitive. HAI-IgM testing could be used to diagnose primary rubella infections in developing countries where expensive EIAs are unaffordable.     

Human polyomavirus type 1 (BK virus) agnoprotein is abundantly expressed but immunologically ignored

Impaired BK virus (BKV)-specific immunity is a key risk factor of polyomavirus-associated nephropathy. We hypothesized that BKV agnoprotein might constitute an important immune target, as it is highly expressed after infection in vitro. We demonstrate abundant expression of BKV agnoprotein in vivo by immunostaining of kidney transplant (KT) biopsy specimens. Antibody responses to the recombinant affinity-purified BKV agnoprotein, large tumor (LT), and VP1 antigens in 146 sera from 38 KT patients and in 19 sera from 16 healthy donors (HD) were compared by enzyme immunoassay. In HD, low titers of anti-agnoprotein immunoglobulin G (IgG) were found in 15% of sera, compared to 41% for anti-LT antigen and 63% for anti-VP1. No anti-BKV IgM was detectable. In KT patients, anti-agnoprotein IgG and IgM were found in 8% and 3.6% of sera, compared to 63% and 18% for anti-LT IgG and IgM and 80% and 41% for anti-VP1 IgG and IgM, respectively. Anti-LT antigen and anti-VP1, but not anti-agnoprotein, activities increased during and after BKV viremia in KT patients. To investigate specific cellular immune responses, we compared levels of gamma interferon production in peripheral blood mononuclear cells (PBMC) of 10 HD and 30 KT patients by enzyme-linked immunospot assay. In HD, the median numbers of gamma interferon spot-forming units per million PBMC for the agnoprotein, LT antigen, and VP1 peptides were 1, 23, and 25, respectively, whereas the responses in KT patients were 2, 24, and 99, respectively. We conclude that BKV agnoprotein, though abundantly expressed in vivo, is poorly recognized immunologically.     

Update on the prevention,diagnosis and management of cytomegalovirus infection during pregnancy

Human cytomegalovirus (CMV) is the leading cause of congenital infection, with morbidity and mortality at birth and sequelae. Each year approximately 1–7% (Rev Med Virol 2010; 20: 311) of pregnant women acquire a primary CMV infection. Of these, about 30–40% transmit infection to their fetuses. The risk of serious fetal injury is greatest when maternal infection develops in the first trimester or early in the second trimester. Between 10 and 15% of congenitally infected infants are acutely symptomatic at birth and most of the survivors have serious long-term complications. Until a few years ago, laboratory testing was not possible to precisely define the maternal immune status, the recent development of advanced serological tests (IgG avidity test, IgM immunoblot and neutralizing antibody testing) allow us to identify, among pregnant women with suspected CMV, those with primary infection who are therefore at high risk of transmitting CMV to the fetus. This is done with the use of a screening test. As most maternal infections are asymptomatic, the only way to disclose primary infection is to implement specific serological testing as early in pregnancy as possible (before week 12–16 of gestation). Given the high risk of mother–fetus transmission and fetal damage, prenatal diagnosis is recommended to women with primary CMV infection contracted in the first half of pregnancy and in case of fetal abnormalities suggestive of infection. The correct interpretation of serological and virological tests followed by appropriate counselling by an expert physician is an effective tool to reduce the number of unnecessary pregnancy terminations by over 70% (Am J Obstet Gynecol 2007; 196: 221.e1).     

Detection of specific IgA antibodies against BK virus by ELISA.

The development and evaluation of an ELISA for analysis of anti-BKV specific IgA antibodies in human sera are described. All children with cancer with a primary BKV infection developed specific IgA antibodies, without any specific symptoms during the infection. Specific IgA was found in 61% of sera from healthy persons containing BKV IgG antibodies, using the chosen cut-off value, and BKV IgM in 4%. These results indicate that IgA production is more persistent than IgM. The high frequency of specific IgA antibodies could either be explained by frequent reactivations or long-lasting persistence of antibodies.