Human Cytomegalovirus Infection In Pregnancy Research Articles

Pitfalls in the Serological Diagnosis of Primary Human Cytomegalovirus Infection in Pregnancy Due to Different Kinetics of IgM Clearance and IgG Avidity Index Maturation.

Primary infection occurs when seronegative women are infected by human cytomegalovirus (HCMV). Diagnosis of primary infection is based on the following: antibody seroconversion, presence of IgM and low IgG avidity index (AI), and presence of DNAemia. The kinetics of HCMV-specific IgM antibody and maturation of AI might be very rapid or long-lasting during primary infection, which makes serological diagnosis insidious. The aims of this study were as follows: (i) to report atypical kinetics of HCMV-specific IgM antibody and AI early after onset of primary HCMV infection in a population of pregnant women, and (ii) to assess the frequency of such results. Altogether, 1309 sequential serum samples collected from 465 pregnant women with primary HCMV infection were included in the study. As a general rule, using the LIAISON®CMVIgMII and LIAISON®CMVIgGAvidityII assays, virus-specific IgM antibody levels decreased, while IgG AI increased over time during the first three months after infection onset. However, early clearance of IgM antibody and/or early IgG AI maturation occurred in 46/426 (10.7%) women. In more details, 20/426 (4.7%) and 26/418 (6.2%) women had undetectable IgM antibody or high IgG AI, respectively, when tested within 1–3 months after well-defined infection onset. Twenty sera from as many women with high IgG AI by the LIAISON assay were further tested for IgG AI by VIDAS®CMVIgGAvidityII and Mikrogen recomLineCMVIgG Avidity assays. Comparable results were obtained with VIDAS, whereas 14/20 sera gave low AI with the Mikrogen assay. In conclusion, about 11% of pregnant women undergoing a primary HCMV infection showed misleading serological results. Additional and appropriate testing might help in reducing the risk of missing HCMV primary infection in pregnancy. Furthermore, preconceptional testing should be strongly recommended.

Phenotype and specificity of T cells in primary human cytomegalovirus infection during pregnancy: IL-7Rpos long-term memory phenotype is associated with protection from vertical transmission.

Congenital human cytomegalovirus (HCMV) infection is the major cause of birth defects and a precise definition of the HCMV-specific T-cell response in primary infection may help define reliable correlates of immune protection during pregnancy. In this study, a high throughput method was used to define the frequency of CD4+ and CD8+ T cells specific for four HCMV proteins in the naïve compartment of seronegative subjects and the effector/memory compartments of subjects with primary/remote HCMV infection. The naïve repertoire displayed comparable frequencies of T cells that were reactive with HCMV structural (pp65, gB and the pentamer gHgLpUL128L) and non-structural (IE-1) proteins. Whereas, following natural infection, the majority of effector/memory CD4+ and CD8+ T cells recognized either gB or IE-1, respectively, and pp65. The pattern of T cell reactivity was comparable at early and late stages of infection and in pregnant women with primary HCMV infection transmitting or not transmitting the virus to the fetus. At an early stage of primary infection, about 50% of HCMV-reactive CD4+ T cells were long-term IL-7Rpos memory cells, while 6–12 months later, the frequency of these cells increased to 70%, approaching 100% in remote infections. In contrast, only 10–20% of HCMV-specific CD8+ T cells were long-term memory cells up to 12 months after infection onset, thereafter increasing to 70% in remote infections. Interestingly, a significantly higher frequency of HCMV-specific CD4+ T cells with a long-term IL-7Rpos memory phenotype was observed in non-transmitting compared to transmitting women. These findings indicate that immunodominance in HCMV infection is not predetermined in the naïve compartment, but is the result of virus-host interactions and suggest that prompt control of HCMV infection in pregnancy is associated with the rapid development of long-term IL-7Rpos memory HCMV-specific CD4+ T cells and a low risk of virus transmission to the fetus.

Primary Human Cytomegalovirus (HCMV) Infection in Pregnancy.

In 0.5-4% of pregnancies, the prospective mother sustains a primary infection with human cytomegalovirus (HCMV). An HCMV infection of the fetus in the first or second trimester can cause complex post-encephalitic impairment of the infant brain, leading to motor and mental retardation, cerebral palsy, epilepsy, retinal defects, and progressive hearing loss. This review is based on pertinent publications from January 2000 to October 2016 that were retrieved by a selective search in PubMed employing the terms "cytomegalovirus and pregnancy" and "congenital cytomegalovirus." 85-90% of all neonates with HCMV infection are asymptomatic at birth. The main long-term sequela is hearing impairment, which develops in 8-15% of these affected children. Hygienic measures can lower the risk of primary HCMV infection in pregnancy by 50-85%. The first randomized and controlled trial (RCT) of passive immunization with an HCMV-specific hyper - immune globulin (HIG) preparation revealed a trend toward a lower risk of congenital transmission of the virus (30% versus 44% with placebo, p = 0.13). The effect of HIG was more marked in the initial non-randomized trial (15% versus 40%, p = 0.02). The RCT also showed HIG to be associated with a higher frequency of fetal growth retardation and premature birth (13% versus 2%, p = 0.06). Valaciclovir is a further, non-approved treatment option. In the absence of an active vaccine against HCMV, counseling about hygienic measures may currently be the single most effective way to prevent congenital HCMV infection. Moreover, HCMV serologic testing is recommended in the guideline of the Association of the Scientific Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF). Further randomized trials of treatment with HIG and with valaciclovir are urgently needed so that the options for the prevention and treatment of congenital HCMV infection can be assessed.

Prospects of a vaccine for the prevention of congenital cytomegalovirus disease.

Congenital human cytomegalovirus (HCMV) infection is one leading cause of childhood disabilities. Prevention of congenital HCMV disease by vaccination has consequently been identified as a priority public healthcare goal. Several vaccine candidates have been introduced in the past that aimed at the prevention of primary HCMV infection in pregnancy. None of these has provided complete protection, and no licensed vaccine is thus far available. An additional level of complexity has been reached by recent studies indicating that the burden of HCMV transmission and disease following non-primary infections in pregnancy may be higher than previously anticipated. Substantial progress in our understanding of the immunobiology of HCMV infection in pregnancy has fostered studies to test revised or novel vaccine strategies. Preventing HCMV transmission has been identified a surrogate endpoint, rendering the conduction of vaccine studies feasible with reasonable effort. Identification of the glycoprotein complex gH/gL/UL128-131 as a mediator of HCMV host cell tropism and evaluation of that complex as a major target of the neutralizing antibody response made manufacturers consider vaccine candidates that include these proteins. Detailed structural analyses of the neutralizing determinants on HCMV glycoprotein B (gB) have revived interest in using this protein in its pre-fusion conformation for vaccine purposes. Studies in pregnant women and in animal models have provided evidence that addressing the T lymphocyte response by vaccination may be crucial to prevent HCMV transmission to the offspring. CD4 T lymphocytes may be of particular importance in this respect. A simultaneous targeting of both the humoral and cellular immune response against HCMV by vaccination thus appears warranted in order to prevent congenital HCMV infection. There is, however, still need for further research to be able to define an immunological correlate of protection against HCMV transmission during pregnancy. This brief review will highlight recent developments in our understanding of the natural history and immunobiology of HCMV infection in pregnancy and their possible impact on the strategies for the development of an HCMV vaccine.

Rapid detection of active human cytomegalovirus infection in pregnancy using loop-mediated isothermal amplification

Understanding the association between congenital human cytomegalovirus (HCMV) infection and active maternal HCMV infection during pregnancy is important for maternal and neonatal healthcare. In the present study, a loop-mediated isothermal amplification (LAMP) method was established for the detection of CMV DNA from whole blood or amniotic fluid samples, using reverse transcription-quantitative polymerase chain reaction. The results of the present study demonstrated that the CMV LAMP assay detection was specific for CMV DNA, whereas it did not detect viral DNA from herpes simplex type 1 (HSV-1), HSV-2, varicella zoster virus, HSV-6 or HSV-7. Sensitivity determination using serially-diluted CMV glycoprotein B-containing plasmids, demonstrated that >10 copies per tube were detectable using the CMV LAMP method. Furthermore, the detection results, using the LAMP method for 336 whole blood samples, demonstrated that at a threshold of 10(1)-10(4) copies per tube, the sensitivity of this method was 86.96-100%, the specificity was 97.24-100%, the positive predictive value was 76.92-100% and the negative predictive value was 99.05-100%. The results for 11 amniotic fluid samples from pregnant women with whole blood CMV-positive and 15 control amniotic fluid samples, indicated that the CMV LAMP assay was sensitive and specific for CMV detection. In conclusion, in the present study, a CMV LAMP method was developed, which was shown to be sensitive, specific and efficient in the detection of HCMV infection. Furthermore, CMV LAMP is capable of detecting active CMV infection in pregnant women. Therefore, the current study provides novel insights into diagnostic approaches for active CMV infection in pregnant women.

Evaluation on clinical application of three testing methods for human cytomegalovirus infection in pregnancy.

The value of ELISA, N-PCR and RT-PCR in clinical practice for pregnant women with HCMV infection was investigated. 5581 pregnant women were screened by ELISA. Among them, 100 cases were positive for IgM (group 1), 69 for both IgM and serous DNA (group 2) and 69 for both IgM and mRNA (group 3). The infectious status, maternal-fetal transmission and pregnancy outcome were monitored. It was demonstrated that the accordance rate of group 3 and group 2 with group 1 was 56.25% and 43.75%, respectively. The maternal-fetal transmission rate in the group 1, 2 and 3 was 19.00%, 40.58% and 46.15%, respectively, with a significant difference found between group 2, 3 and group 1 (P < 0.01). Incidence of spontaneous abortion, fetal death, fetal abnormality and neonatal death in group 1, 2 and 3 was 10.00%, 15.94% and 30.77%, respectively, and that of group 3, 2 was 4 and 2 times as much as that of group 1, respectively (OR = 4.00, P < 0.001; OR = 2.343, P < 005, respectively). It was concluded that HCMV-IgM(+) can only be considered as an screening indicator for pregnant women with HCMV infection, while IgM(+) combined with serous DNA(+) or mRNA(+) indicates active infection and has a high incidence of maternal-fetal transmission and abnormal pregnancy outcome.

Diagnosis and implications of human cytomegalovirus infection in pregnancy

Early this century, the term cytomegalic inclusion disease (CID) was used to designate the cellular changes characterized by enlargement and typical intranuclear inclusions observed in tissues of fetuses and infants with a fatal illness. In 1957, Smith and Weller et al, identified the causative agent of CID, which was named cytomegalovirus (CMV) by Weller in 1960. By 1971, it was clear that congenital human CMV (HCMV) infection was an important health problem. Since then, many advances have been made in the diagnosis, therapy, and knowledge of the epidemiology of congenital HCMV infection. However, most of these improvements, particularly those concerning diagnostic technologies and development of antiviral drugs, have been the result of the powerful effort to reduce the devastating impact of HCMV infections in AIDS and transplanted patients. Indeed, it is disappointing to observe that in the year 2000 CID does still occur, that HCMV is still recognized as the leading cause of congenital infection and the leading infectious cause of mental retardation and deafness, and, most important, that no active prevention is available for seronegative women. Moreover, because of the limited possibilities of prophylaxis and treatment, and the misuse of the currently available serologic assays, the issue of whether the determination of HCMV antibody status for women of childbearing age is justified has become a matter of debate.

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.

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

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