Epidemiology, pathogenesis and prevention of congenital cytomegalovirus infection

Sirtuin 2 promotes human cytomegalovirus replication by regulating cell cycle progression

IMPORTANCE

This study expands the growing understanding that protein acetylation is a highly regulated molecular toggle of protein function in both host anti-viral defense and viral replication. We describe a pro-viral role for the human enzyme SIRT2, showing that its deacetylase activity supports HCMV replication. By integrating quantitative proteomics, flow cytometry cell cycle assays, microscopy, and functional virology assays, we investigate the temporality of SIRT2 functions and substrates. We identify a pro-viral role for the SIRT2 deacetylase activity via regulation of CDK2 K6 acetylation and the G1-S cell cycle transition. These findings highlight a link between viral infection, protein acetylation, and cell cycle progression.

Pre- and postnatal brain magnetic resonance imaging in congenital cytomegalovirus infection: a case report and a review of the literature

Background

Congenital cytomegalovirus infection (cCMV) is the most common known viral cause of neurodevelopmental delay in children. The risk of severe cerebral abnormalities and neurological sequelae is greatest when the infection occurs during the first trimester of pregnancy. Pre- and postnatal imaging can provide additional information and may help in the prediction of early neurological outcome.

Case presentation

This report presents the case of a newborn with cCMV infection with diffuse parenchymal calcifications, white matter (WM) abnormalities and cerebellar hypoplasia on postnatal brain imaging after magnetic resonance imaging (MRI) and neurosonogram (NSG) at 30 weeks showing lenticulostriate vasculopathy, bilateral temporal cysts and normal gyration pattern according to the gestational age (GA). No calcifications were seen on prenatal imaging.

Conclusion

cCMV infection can still evolve into severe brain damage after 30 weeks of GA. For this reason, a two-weekly follow-up by fetal NSG with a repeat in utero MRI (iuMRI) in the late third trimester is recommended in cases with signs of active infection.

Association Between First-Trimester Maternal Cytomegalovirus Infection and Stillbirth: A Prospective Cohort Study

BACKGROUND

Given that the time lag between cytomegalovirus (CMV) screening and diagnosed testing, a better knowledge of the association between pregnant women with CMV screening test positive and stillbirth in an epidemiological perspective was required to assist people being counseled reframe their pregnancy and birth plans based on the magnitude of the risk.

METHODS

This study recruited 44048 eligible pregnant women from March 13, 2013 to December 31, 2019. Serological tests including CMV-specific IgM and IgG, and IgG avidity index were used to screen for maternal CMV infection and were measured by automated chemiluminescence immunoassay. The association was assessed using the inverse probability of group-weighted multivariate-adjusted log-binomial models.

RESULTS

A total of 540 infants ended with a stillbirth (12.3 per 1000 pregnancies), and 2472 pregnancies with maternal CMV infection were screened out (56.1 per 1000 pregnancies) among all eligible pregnancies. In the comparison analysis, 326 infants ended with a stillbirth (86.6 per 1000 pregnancies) in the maternal CMV infection group compared with 214 infants (7.8 per 1000 pregnancies) in the group where mothers were not infected with CMV (RR 12.17; 95% CI 9.43-15.71). After excluding the pregnancies of stillbirth with birth defects, a strong association between the two groups was still observed (RR 9.38; 95% CI 6.92-12.70).

CONCLUSION

Our findings quantified the risk of a woman having a baby with stillbirth if she had a positive serologic CMV screening test in her first trimester, and supported the value of using CMV serologic tests as part of regular testing in pregnant women.

TRIAL REGISTRATION

Registered in Chinese Clinical Trial Registry Center; registration number, ChiCTR1800016635; registration date, 06/14/2018 (Retrospectively registered); URL of trial registry record, https://www.chictr.org.cn/showproj.aspx?proj=28300.

The human cytomegalovirus protein pUL13 targets mitochondrial cristae architecture to increase cellular respiration during infection

Viruses modulate mitochondrial processes during infection to increase biosynthetic precursors and energy output, fueling virus replication. In a surprising fashion, although it triggers mitochondrial fragmentation, the prevalent pathogen human cytomegalovirus (HCMV) increases mitochondrial metabolism through a yet-unknown mechanism. Here, we integrate molecular virology, metabolic assays, quantitative proteomics, and superresolution confocal microscopy to define this mechanism. We establish that the previously uncharacterized viral protein pUL13 is required for productive HCMV replication, targets the mitochondria, and functions to increase oxidative phosphorylation during infection. We demonstrate that pUL13 forms temporally tuned interactions with the mitochondrial contact site and cristae organizing system (MICOS) complex, a critical regulator of cristae architecture and electron transport chain (ETC) function. Stimulated emission depletion superresolution microscopy shows that expression of pUL13 alters cristae architecture. Indeed, using live-cell Seahorse assays, we establish that pUL13 alone is sufficient to increase cellular respiration, not requiring the presence of other viral proteins. Our findings address the outstanding question of how HCMV targets mitochondria to increase bioenergetic output and expands the knowledge of the intricate connection between mitochondrial architecture and ETC function.

Apoptosis Disorder, a Key Pathogenesis of HCMV-Related Diseases

Human cytomegalovirus (HCMV) belongs to the β-herpesvirus family, which is transmitted in almost every part of the world and is carried by more than 90% of the general population. Increasing evidence indicates that HCMV infection triggers numerous diseases by disrupting the normal physiological activity of host cells, particularly apoptosis. Apoptosis disorder plays a key role in the initiation and development of multiple diseases. However, the relationship and molecular mechanism of HCMV-related diseases and apoptosis have not yet been systematically summarized. This review aims to summarize the role of apoptosis in HCMV-related diseases and provide an insight into the molecular mechanism of apoptosis induced by HCMV infection. We summarize the literature on HCMV-related diseases and suggest novel strategies for HCMV treatment by regulating apoptosis.

UL26 Attenuates IKKβ-Mediated Induction of Interferon-Stimulated Gene (ISG) Expression and Enhanced Protein ISGylation during Human Cytomegalovirus Infection

Viruses must negotiate cellular antiviral responses in order to replicate. Human cytomegalovirus (HCMV) is a prevalent betaherpesvirus that encodes a number of viral gene products that modulate cellular antiviral signaling. The HCMV U_L26 gene has previously been found to attenuate cytokine-activated NF-κB signaling, yet the role that U_L26 plays in modulating the host cell's global transcriptional response to infection is not clear. Here, we find that infection with a U_L26 deletion virus (ΔU_L26) induces a proinflammatory transcriptional environment that includes substantial increases in the expression of cytokine signaling genes relative to wild-type HCMV. These increases include NF-κB-regulated genes as well as interferon-stimulated genes (ISGs), such as ISG15 and bone marrow stromal cell antigen 2 (BST2). The ΔU_L26 mutant-mediated induction of ISG15 expression was found to drive increases in global protein ISGylation during ΔU_L26 mutant infection. However, short hairpin RNA (shRNA) and CRISPR-mediated targeting of ISG15 indicated that its induction does not restrict HCMV infection. In contrast, shRNA-mediated targeting of BST2 demonstrated that BST2 restricts HCMV cell-to-cell spread. In addition, the increased expression of both of these ISGs and the global enhancement in protein ISGylation were found to be dependent on the activity of the canonical inhibitor of NF-κB kinase beta (IKKβ). Both CRISPR-based and pharmacologically mediated inhibition of IKKβ blocked the induction of ISG15 and BST2. These results suggest significant cross-talk between the NF-κB and interferon signaling pathways and highlight the importance of IKK signaling and the HCMV U_L26 protein in shaping the antiviral response to HCMV.IMPORTANCE Modulation of cellular antiviral signaling is a key determinant of viral pathogenesis. Human cytomegalovirus (HCMV) is a significant source of morbidity in neonates and the immunosuppressed that contains many genes that modulate antiviral signaling, yet how these genes contribute to shaping the host cell's transcriptional response to infection is largely unclear. Our results indicate that the HCMV U_L26 protein is critical in preventing the establishment of a broad cellular proinflammatory transcriptional environment. Further, we find that the host gene IKKβ is an essential determinant governing the host cell's antiviral transcriptional response. Given their importance to viral pathogenesis, continuing to elucidate the functional interactions between viruses and the cellular innate immune response could enable the development of therapeutic strategies to limit viral infection.

Meal for Two: Human Cytomegalovirus-Induced Activation of Cellular Metabolism

Viruses are parasites that depend on the host cell’s metabolic resources to provide the energy and molecular building blocks necessary for the production of viral progeny. It has become increasingly clear that viruses extensively modulate the cellular metabolic network to support productive infection. Here, we review the numerous ways through which human cytomegalovirus (HCMV) modulates cellular metabolism, highlighting known mechanisms of HCMV-mediated metabolic manipulation and identifying key outstanding questions that remain to be addressed.

Frequent pUL27 Variations in HIV-Infected Patients

OBJECTIVE

Drug-resistant isolates of human cytomegalovirus (HCMV) have led to the development of new anti-HCMV drugs. Maribavir (MBV) is a novel inhibitor of the HCMV viral kinase. Resistance to MBV is mapped to gene UL27, a viral nuclear protein. In this study, we investigated UL27 polymorphisms in MBV-naive HIV-positive and HCMV congenitally infected clinical samples.

METHODS

DNA was extracted from 20 CMV-positive HIV (9/20) and congenitally infected (11/20) patients and used for UL27 polymerase chain reaction amplification. Sanger sequencing and multiple sequence alignment of products was performed.

RESULTS

K90 was the most prevalent polymorphism in both HIV-positive and congenitally infected patients. Polymorphisms Q54, D123, and R107 (10%) were seen in more than one sample. There were significantly more polymorphisms in the HIV-positive samples (p = 0.038).

CONCLUSION

HCMV pUL27 is highly variable in adult immunocompromised HIV-positive patients.

The immunological underpinnings of vaccinations to prevent cytomegalovirus disease

A universal cytomegalovirus (CMV) vaccination promises to reduce the burden of the developmental damage that afflicts up to 0.5% of live births worldwide. An effective vaccination that prevents transplacental transmission would reduce CMV congenital disease and CMV-associated still births and leave populations less susceptible to opportunistic CMV disease. Thus, a vaccination against this virus has long been recognized for the potential of enormous health-care savings because congenital damage is life-long and existing anti-viral options are limited. Vaccine researchers, industry leaders, and regulatory representatives have discussed the challenges posed by clinical efficacy trials that would lead to a universal CMV vaccine, reviewing the links between infection and disease, and identifying settings where disrupting viral transmission might provide a surrogate endpoint for disease prevention. Reducing the complexity of such trials would facilitate vaccine development. Children and adolescents are the targets for universal vaccination, with the expectation of protecting the offspring of immunized women. Given that a majority of females worldwide experience CMV infection during childhood, a universal vaccine must boost natural immunity and reduce transmission due to reactivation and re-infection as well as primary infection during pregnancy. Although current vaccine strategies recognize the value of humoral and cellular immunity, the precise mechanisms that act at the placental interface remain elusive. Immunity resulting from natural infection appears to limit rather than prevent reactivation of latent viruses and susceptibility to re-infection, leaving a challenge for universal vaccination to improve upon natural immunity levels. Despite these hurdles, early phase clinical trials have achieved primary end points in CMV seronegative subjects. Efficacy studies must be expanded to mixed populations of CMV-naive and naturally infected subjects to understand the overall efficacy and potential. Together with CMV vaccine candidates currently in clinical development, additional promising preclinical strategies continue to come forward; however, these face limitations due to the insufficient understanding of host defense mechanisms that prevent transmission, as well as the age-old challenges of reaching the appropriate threshold of immunogenicity, efficacy, durability and potency. This review focuses on the current understanding of natural and CMV vaccine-induced protective immunity.

Cytomegalovirus-mediated activation of pyrimidine biosynthesis drives UDP-sugar synthesis to support viral protein glycosylation

Human cytomegalovirus (HCMV) induces numerous changes to the host metabolic network that are critical for high-titer viral replication. We find that HCMV infection substantially induces de novo pyrimidine biosynthetic flux. This activation is important for HCMV replication because inhibition of pyrimidine biosynthetic enzymes substantially decreases the production of infectious virus, which can be rescued through medium supplementation with pyrimidine biosynthetic intermediates. Metabolomic analysis revealed that pyrimidine biosynthetic inhibition considerably reduces the levels of various UDP-sugar metabolites in HCMV-infected, but not mock-infected, cells. Further, UDP-sugar biosynthesis, which provides the sugar substrates required for glycosylation reactions, was found to be induced during HCMV infection. Pyrimidine biosynthetic inhibition also attenuated the glycosylation of the envelope glycoprotein B (gB). Both glycosylation of gB and viral growth were restored by medium supplementation with either UDP-sugar metabolites or pyrimidine precursors. These results indicate that HCMV drives de novo-synthesized pyrimidines to UDP-sugar biosynthesis to support virion protein glycosylation. The importance of this link between pyrimidine biosynthesis and UDP-sugars appears to be partially shared among diverse virus families, because UDP-sugar metabolites rescued the growth attenuation associated with pyrimidine biosynthetic inhibition during influenza A and vesicular stomatitis virus infection, but not murine hepatitis virus infection. In total, our results indicate that viruses can specifically modulate pyrimidine metabolic flux to provide the glycosyl subunits required for protein glycosylation and production of high titers of infectious progeny.

Epidemiological survey of human cytomegalovirus antibody levels in children from Southeastern China

Background

This study investigated infection status and distribution of human cytomegalovirus (HCMV) serum markers in hospitalized children from the Wenzhou region.

Methods

This survey was performed on 10,147 hospitalized children from birth to 14 years of age in Southeastern China (Wenzhou region) from March 2010 to March 2013. IgM and IgG antibodies to HCMV were quantitatively detected by chemiluminescence immunoassay (CLIA). HCMV IgM or IgG detection rates, concentration, and distribution in various age groups were retrospectively analyzed.

Results

In this study of hospitalized children, the overall rates of HCMV IgM⁺ and IgG⁺ were 10.8% (1,099/10,147) and 83.0% (8,425/10,147), respectively. The lowest HCMV IgM⁺ rate (1.0%, P < 0.001) was observed in the group of patients <28 days of age whereas the highest HCMV IgM⁺ rate (19.9%, P < 0.001) occurred in the 28 days ~ 5 months old group. However, the concentrations of HCMV specific IgM in all age groups were not significantly different (P > 0.05). The HCMV IgG⁺ rate was highest in the <28 days group (98.1%, P < 0.001). The 28 days ~ 5 months old group had the lowest HCMV specific IgG concentrations (median, 133.9 AU/mL, P < 0.001). Among 1,099 HCMV IgM⁺ children, 405 (36.9%) were diagnosed with respiratory infections which pneumonia accounted for 18.2% (200/1,099) of the total population. However, children with respiratory infections had the lowest HCMV IgG concentrations (median, 161.1 AU/mL, P < 0.05).

Conclusions

HCMV specific antibody responses are very common in hospitalized children with respiratory infection in Wenzhou region. Protection against HCMV airway infection needs greater emphasis and further studies will be helpful to reveal the role of HCMV in children respiratory disease.

Distinct domains within the human cytomegalovirus U(L)26 protein are important for wildtype viral replication and virion stability

The human cytomegalovirus (HCMV) U_L26 gene encodes a virion protein that is important for high titer viral replication. To identify specific domains within the U_L26 protein that contribute to viral infection, we created a panel of site-directed U_L26 mutant viruses and assessed their impact on phenotypes attributed to U_L26. We find that the C-terminal 38 amino acids of the U_L26 protein are absolutely necessary for U_L26 function. A stop-insertion mutant that produced a truncated U_L26 protein lacking this region behaved identically to U_L26-null viruses. This included reduced accumulation of IE1 protein at early time points, smaller plaque size, reduced virion stability, and growth with similarly attenuated kinetics. This C-terminal truncation decreased the amount of U_L26 packaged into the virion resulting in reduced delivery of U_L26 to newly infected cells. Further, this C-terminal truncated U_L26 exhibited substantially reduced nuclear localization compared to wildtype U_L26. Translation of U_L26 mRNA is initiated from two separate in frame methionines that give rise to a long and a short isoform of U_L26. We find that the N-terminal 34 amino acids, which are unique to the long isoform of U_L26, are also important for the function of the U_L26 protein. A viral mutant that produces only the short isoform of U_L26 and lacks these N-terminal 34 amino acids exhibits delayed IE1 accumulation, and demonstrates intermediate defects in viral plaque size, virion stability and viral growth kinetics. Ablation of the short U_L26 isoform in the presence of the long U_L26 isoform did not impact any of the in vitro phenotypes tested. These experiments highlight important domains within the U_L26 protein that contribute to HCMV infection.

Recent developments in human cytomegalovirus diagnosis

Since the early 1990s, great efforts have been made in the field of human cytomegalovirus (HCMV) diagnosis. Besides HCMV diagnosis in immunosuppressed patients (solid organ transplant recipients, hematopoietic stem cell transplant patients and AIDS patients), diagnosis in connection with congenital HCMV infection is of great interest. This review focuses on the development and clinical utility of serological assays, as well as on virological tests (molecular and nonmolecular assays). Interpretation of these tests is strongly dependent on the patient group (solid organ transplant recipients and hematopoietic stem cell transplant patients) and whether the tests are used for screening, risk stratification or diagnosis. Furthermore, a better understanding of HCMV infection has led to new approaches in HCMV diagnosis and monitoring. Thus, assays for viral resistance testing and assays for monitoring the HCMV-specific cellular immune response are increasingly important for the guidance of antiviral therapy.

Functional exhaustion of CD4+ T lymphocytes during primary cytomegalovirus infection

Human CMV establishes lifelong persistence after primary infection. Chronic CMV infection is associated with intermittent viral reactivation inducing high frequencies of CD4+ T lymphocytes with potent antiviral and helper properties. Primary CMV infection is characterized by an intense viral replication lasting for several months. The impact of this prolonged exposure to high Ag loads on the functionality of CD4+ T cells remains incompletely understood. In pregnant women with primary CMV infection, we observed that CMV-specific CD4+ T lymphocytes had a decreased capacity to proliferate and to produce IL-2. A very large proportion of CMV-specific CD4+ T cells had downregulated the expression of CD28, a costimulatory molecule centrally involved in the production of IL-2. Unexpectedly, both CD28+ and CD28+ CD4+ T cells produced low levels of IL-2. This defective production of IL-2 was part of a larger downregulation of cytokine production. Indeed, CMV-specific CD4+ T cells produced lower amounts of IFN-γ and TNF-α and showed lower functional avidity during primary as compared with chronic infection. Increased programmed death-1 expression was observed in CD28+ CMV-specific CD4+ T cells, and programmed death-1 inhibition increased proliferative responses. These results indicate that primary CMV infection is associated with the exhaustion of CMV-specific CD4+ T cells displaying low functional avidity for viral Ags.

HCMV targets the metabolic stress response through activation of AMPK whose activity is important for viral replication

Human Cytomegalovirus (HCMV) infection induces several metabolic activities that have been found to be important for viral replication. The cellular AMP-activated protein kinase (AMPK) is a metabolic stress response kinase that regulates both energy-producing catabolic processes and energy-consuming anabolic processes. Here we explore the role AMPK plays in generating an environment conducive to HCMV replication. We find that HCMV infection induces AMPK activity, resulting in the phosphorylation and increased abundance of several targets downstream of activated AMPK. Pharmacological and RNA-based inhibition of AMPK blocked the glycolytic activation induced by HCMV-infection, but had little impact on the glycolytic pathway of uninfected cells. Furthermore, inhibition of AMPK severely attenuated HCMV replication suggesting that AMPK is an important cellular factor for HCMV replication. Inhibition of AMPK attenuated early and late gene expression as well as viral DNA synthesis, but had no detectable impact on immediate-early gene expression, suggesting that AMPK activity is important at the immediate early to early transition of viral gene expression. Lastly, we find that inhibition of the Ca²⁺-calmodulin-dependent kinase kinase (CaMKK), a kinase known to activate AMPK, blocks HCMV-mediated AMPK activation. The combined data suggest a model in which HCMV activates AMPK through CaMKK, and depends on their activation for high titer replication, likely through induction of a metabolic environment conducive to viral replication.

Human Cytomegalovirus (HCMV) is a ubiquitous human pathogen that is a major cause of birth defects. HCMV can also cause severe disease in immunocompromised individuals including transplant recipients, leukemia patients and those infected with HIV. It is clear that upon infection, HCMV takes control of numerous cellular processes that are important for the virus to generate the next round of infectious virions. We have previously found that upon infection, HCMV reprograms the metabolic activity of the host-cell. Here, we find that this metabolic reprogramming largely depends on the viral activation of a cellular protein called the AMP-activated protein kinase (AMPK). AMPK is a central regulator of cellular energy production that is typically only activated when cellular energy stores are very low. Our results indicate that HCMV-mediated activation of AMPK is necessary to flip the metabolic switch thereby driving host-cell metabolic activation and viral replication. As inhibition of AMPK blocked viral replication, and had little impact on uninfected host-cell metabolism, targeting AMPK could have therapeutic potential to treat HCMV-associated disease.

Human cytomegalovirus induces the activity and expression of acetyl-coenzyme A carboxylase, a fatty acid biosynthetic enzyme whose inhibition attenuates viral replication

We have previously reported that human cytomegalovirus (HCMV) infection induces large-scale changes to host cell glycolytic, nucleic acid, and phospholipid metabolism. Here we explore the viral mechanisms involved in fatty acid biosynthetic activation. Our results indicate that HCMV targets ACC1, the rate-limiting enzyme of fatty acid biosynthesis, through multiple mechanisms. HCMV infection was found to activate ACC1 expression, increasing the abundance of both ACC1 mRNA and protein. Viral gene expression but not viral DNA replication was found to be necessary for HCMV-mediated induction of ACC1 levels. HCMV infection was also found to increase the proteolytic processing of SREBP-2, a transcription factor whose proteolytic cleavage is known to activate a variety of phospholipid metabolic genes. Processing of SREBP-2 was found to be dependent on mTOR activity; pharmaceutical inhibition of mTOR blocked HCMV-induced SREBP-2 processing and prevented the induction of fatty acid biosynthesis and ACC1 expression. Independent of the increases in ACC1 expression, HCMV infection also induced ACC1's enzymatic activity. Inhibition of ACC1 through either RNA interference (RNAi) or inhibitor treatment was found to attenuate HCMV replication, and HCMV replication was sensitive to ACC1 inhibition even at the later stages of infection, suggesting a late role for fatty acid biosynthesis during HCMV replication. These findings indicate that HCMV infection actively modulates numerous functional aspects of a key metabolic regulatory enzyme that is important for high-titer viral replication.

Inhibition of calmodulin-dependent kinase kinase blocks human cytomegalovirus-induced glycolytic activation and severely attenuates production of viral progeny

Viruses depend on the host cell to provide the energy and biomolecular subunits necessary for production of viral progeny. We have previously reported that human cytomegalovirus (HCMV) infection induces dramatic changes to central carbon metabolism, including glycolysis, the tricarboxylic acid (TCA) cycle, fatty acid biosynthesis, and nucleotide biosynthesis. Here, we explore the mechanisms involved in HCMV-mediated glycolytic activation. We find that HCMV virion binding and tegument protein delivery are insufficient for HCMV-mediated activation of glycolysis. Viral DNA replication and late-gene expression, however, are not required. To narrow down the list of cellular pathways important for HCMV-mediated [corrected] activation of glycolysis, we utilized pharmaceutical inhibitors to block pathways reported to be both involved in metabolic control and activated by HCMV infection. We find that inhibition of calmodulin-dependent kinase kinase (CaMKK), but not calmodulin-dependent kinase II (CaMKII) or protein kinase A (PKA), blocks HCMV-mediated activation of glycolysis. HCMV infection was also found to target calmodulin-dependent kinase kinase 1 (CaMKK1) expression, increasing the levels of CaMKK1 mRNA and protein. Our results indicate that inhibition of CaMKK has a negligible impact on immediate-early-protein accumulation yet severely attenuates production of HCMV viral progeny, reduces expression of at least one early gene, and blocks viral DNA replication. Inhibition of CaMKK did not affect the glycolytic activation induced by another herpes virus, herpes simplex virus type 1 (HSV-1). Furthermore, inhibition of CaMKK had a much smaller impact on HSV-1 replication than on that of HCMV. These data suggest that the role of CaMKK during the viral life cycle is, in this regard, HCMV specific. Taken together, our results suggest that CaMKK is an important factor for HCMV replication and HCMV-mediated glycolytic activation.

Guidelines on CMV congenital infection

Congenital cytomegalovirus (CMV) infection occurs in 0.6-0.7% of all newborns and is the most prevalent infection-related cause of congenital neurological handicap. Vertical transmission occurs in around 30% of cases, but the fetus is not always affected. Symptomatic newborns at birth have a much higher risk of suffering severe neurological sequelae. Detection of specific IgG and IgM and IgG avidity seem to be the most reliable tests to identify a primary infection but interpretation in a clinical context may be difficult. If a seroconversion is documented or a fetal infection is suspected by ultrasound markers, an amniocentesis should be performed to confirm a vertical transmission. In the absence of a confirmed fetal infection with fetal structural anomalies, a pregnancy termination should be discouraged. Fetal prognosis is mainly correlated to the presence of brain damage. Despite promising results with the use of antiviral drugs and CMV hyperimmune globulin (HIG), results have to be interpreted with caution. Pregnant women should not be systematically tested for CMV during pregnancy. Managing CMV screening should be restricted to pregnancies where a primary infection is suspected or among women at high risk. The magnitude of congenital CMV disease and the value of interventions to prevent its transmission or to decrease the sequelae need to be established before implementing public health interventions. In this paper, aspects of CMV infection in the pregnant woman and her infant are reviewed.

Systems-level metabolic flux profiling identifies fatty acid synthesis as a target for antiviral therapy

Viruses rely on the metabolic network of their cellular hosts to provide energy and building blocks for viral replication. We developed a flux measurement approach based on liquid chromatography-tandem mass spectrometry to quantify changes in metabolic activity induced by human cytomegalovirus (HCMV). This approach reliably elucidated fluxes in cultured mammalian cells by monitoring metabolome labeling kinetics after feeding cells (13)C-labeled forms of glucose and glutamine. Infection with HCMV markedly upregulated flux through much of the central carbon metabolism, including glycolysis. Particularly notable increases occurred in flux through the tricarboxylic acid cycle and its efflux to the fatty acid biosynthesis pathway. Pharmacological inhibition of fatty acid biosynthesis suppressed the replication of both HCMV and influenza A, another enveloped virus. These results show that fatty acid synthesis is essential for the replication of two divergent enveloped viruses and that systems-level metabolic flux profiling can identify metabolic targets for antiviral therapy.

Detection of human cytomegalovirus in dental plaque from individual periodontal sites by real-time polymerase chain reaction

OBJECTIVE

The aim was to evaluate three primer-probe sets and real-time polymerase chain reaction (PCR) for the detection of human cytomegalovirus (HCMV) in dental plaque from individual periodontal sites.

STUDY DESIGN

Fifty subgingival plaque specimens from 13 healthy subjects (on average at least 2 healthy and 2 periodontal disease sites per subject) and 50 saliva specimens from 24 subjects, including 16 controls, were assessed using 3 primer-probe sets (polymerase [POL], glycoprotein B [gB], and US14) and real-time PCR. Kappa statistics were performed to measure agreement between the primer-probe sets.

RESULTS

There was excellent agreement between the gB and POL primers in the detection of HCMV (kappa statistic = 0.85 [95% confidence interval 0.71-0.99]), yielding a prevalence of 4% (2 out of 50) at individual periodontal disease sites and a similar rate of 8.8% (3 out of 34) in saliva.

CONCLUSION

Human cytomegalovirus was infrequently detected in dental plaque. Of 3 primer-probe sets evaluated, those targeting the POL and gB genes were more accurate in the detection of HCMV than that targeting US14.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.

Risk factors for and clinical outcome of congenital cytomegalovirus infection in a peri-urban West-African birth cohort

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the most prevalent congenital infection worldwide. Epidemiology and clinical outcomes are known to vary with socio-economic background, but few data are available from developing countries, where the overall burden of infectious diseases is frequently high.

METHODOLOGY/PRINCIPAL FINDINGS

As part of an ongoing birth cohort study in The Gambia among term infants, urine samples were collected at birth and tested by PCR for the presence of CMV DNA. Risk factors for transmission and clinical outcome were assessed, including placental malaria infection. Babies were followed up at home monthly for morbidity and anthropometry, and at one year of age a clinical evaluation was performed. The prevalence of congenital CMV infection was 5.4% (40/741). A higher prevalence of hepatomegaly was the only significant clinical difference at birth. Congenitally infected children were more often first born babies (adjusted odds ratio (OR) 5.3, 95% confidence interval (CI) 2.0-13.7), more frequently born in crowded compounds (adjusted OR 2.9, 95%CI 1.0-8.3) and active placental malaria was more prevalent (adjusted OR 2.9, 95%CI 1.0-8.4). These associations were corrected for maternal age, bed net use and season of birth. During the first year of follow up, mothers of congenitally infected children reported more health complaints for their child.

CONCLUSIONS/SIGNIFICANCE

In this study, the prevalence of congenital CMV among healthy neonates was much higher than previously reported in industrialised countries, and was associated with active placental malaria infection. There were no obvious clinical implications during the first year of life. The effect of early life CMV on the developing infant in the Gambia could be mitigated by environmental factors, such as the high burden of other infections.

Congenital cytomegalovirus infection in pregnancy: a case report of fetal death in a CMV-infected woman

OBJECTIVES

The human cytomegalovirus (CMV) is universally distributed among human populations as one of the most common cause of congenital infection with an incidence of about 0.15-2.0% in developed countries. However, controversial data concerning intrauterine fetal death caused by CMV infection exist.

METHOD

A case report.

RESULTS

In this case report we present a stillbirth in the 18th week of pregnancy, caused by a maternal serological and fetal histological congenital CMV infection.

CONCLUSION

Every attending physician and obstetrician should be aware of the possibility of a primary or even recurrent congenital CMV infection that could be a reason for sudden unknown congenital fetal death.

Clinical findings and adverse outcome in neonates with symptomatic congenital cytomegalovirus (SCCMV) infection

INTRODUCTION

Congenital cytomegalovirus (CCMV) infection is a common neonatal infection affecting 1% of all live births, 10% of which are symptomatic. Many of these infants have long-term sequelae. The objective is to document the clinical presentation of SCCMV infection in neonates, the frequency of sequelae and severity of adverse neurologic outcomes and risk factors.

METHODS

A review and analysis of all symptomatic infants diagnosed with SCCMV infection are given. SCCMV was defined as a diagnosis of CCMV infection in the first three weeks of life in the presence of any clinical manifestations. Outcome data from 2 years of age and later are analyzed.

RESULTS

There were 104 patients identified as having SCCMV infection and of these 42 cases had definite infection. The common findings at presentation were hepatosplenomegaly 19/42 (45%), thrombocytopenia 21/42 (50%), elevated transaminases 21/42(50%), abnormal cranial US scan 24/41(56%), abnormal head CT scan 29/41(71%) and abnormal brain MRI 17/19(89%). The risk factors for an adverse outcome including death or deafness or blindness or moderate to severe neurological deficits included an abnormal cranial US scan (OR 8.5), abnormal head CT scan (OR 21) and abnormal brainstem auditory evoked responses (BAER) (OR 8.7).

CONCLUSIONS

There was only three (7%) patients without any deficits and severely affected infants have been identified with a diverse clinical presentation, reinforcing the importance of CMV as a major public health problem.