Significance of Cytomegalovirus gB Genotypes in Adult Patients Undergoing Hematopoietic Stem Cell Transplantation: Insights from a Single-Centre Investigation

INTRODUCTION

Cytomegalovirus (CMV) infection is a major clinical issue after allogeneic hematopoietic stem cell transplantation (HSCT). The CMV envelope glycoproteins are key in viral pathogenesis; the glycoprotein B (gB) encoded by the UL55 gene might be an important determinant of viral virulence and disease severity marker in patients treated with allogeneic HSCT. Our aim was to investigate the molecular diversity of CMV gB and inquire into the associations between UL55 gene variations and clinical manifestations in adult patients treated with allogeneic HSCT.

RESULTS

The most prevalent genotypes were gB1 and gB4 (11/27, 40.7%). Patients with genotype gB1 infection had earlier platelet engraftment (p < 0.033) and less frequent minimal/measurable residual disease post HSCT than those without this genotype. Patients with gB4 glycoprotein infection had a significantly lower CD4+/CD8+ ratio at D90 (p < 0.026). Interestingly, patients with gB5 glycoprotein infection had shorter overall survival from base condition diagnosis (p < 0.042), as well as shorter overall survival after HSCT (p < 0.036). Acute GvHD was noted more frequently in those with mixed-genotype infection (p = 0.047).

MATERIAL AND METHODS

The study included fifty-nine adult patients treated with allogeneic HSCT. Peripheral venous blood was sampled typically per week, with detection of CMV performed by quantitative real-time PCR. Multiplex nested PCR was used to determine specific gB genotypes, which were then statistically compared vis-à-vis specific clinical variables.

CONCLUSIONS

Our study points to variations in the viral UL55 locus imparting both beneficial (earlier platelet engraftment, less frequent MRD post HSCT) and adverse effects (shorter overall survival, more frequent acute GvHD, less frequent 100% chimerism at day 90) to the transplanted host. Comprehensive molecular investigations are necessary to validate this apparent duality, as the potential benefits of CMV could perhaps be utilized for the benefit of the patient in the future.

Distribution of CMV envelope glycoprotein B, H and N genotypes in infants with congenital cytomegalovirus symptomatic infection

Background

Cytomegalovirus (CMV) is the leading cause of congenital infections worldwide and contributes to long-term sequelae in neonates and children. CMV envelope glycoproteins play a vital role in virus entry and cell fusion. The association between CMV polymorphisms and clinical outcomes remains controversial. The present study aims to demonstrate the distribution of glycoprotein B (gB), H (gH) and N (gN) genotypes in congenitally CMV (cCMV) infected symptomatic infants and attempts to figure out the association between viral glycoprotein genotypes and clinical outcomes.

Methods

Genotyping of gB, gH and gN was performed in 42 cCMV symptomatic infants and 149 infants with postnatal CMV (pCMV) infection in Children's hospital of Fudan university. Nested PCR, gene sequencing and phylogenetic analyses were used to identify the genotypes.

Results

Our study demonstrated that: 1. The CMV gB1, gH1 and gN1 were the predominant genotypes among symptomatic cCMV infected infants, while gB1, gH1 and gN3a were more prevalent in pCMV group. gH1 genotype has a significant association with symptomatic cCMV infection (p = 0.006). 2. No significant correlation was found between CMV genotypes and hearing impairment. However, gH1 was more prevalent among cCMV infected infants with moderate/severe hearing loss although without statistical difference (p = 0.130). 3. gB3 was more prevalent among infants with skin petechiae (p = 0.049) and found to be associated with an increased risk of skin petechiae (OR = 6.563). The gN4a subtype was significantly associated with chorioretinitis due to cCMV infection (p = 0.007). 4. Urine viral loads were not significantly associated with different genotypes or hearing impairment among symptomatic cCMV infected infants.

Conclusions

Our findings demonstrated the overall distribution of gB, gH and gN genotypes in infants with symptomatic cCMV infection in Shanghai for the first time. The findings in our study may suggest a possible association between gH1 genotype and early infancy hearing loss. gB3 genotype was associated with a 6.5-fold increased risk of petechiae while gN4a strongly correlated with chorioretinitis due to cCMV infection. No significant correlation was found between urine viral loads and CMV genotypes or hearing impairment in cCMV infected infants.

Common Polymorphisms in the Glycoproteins of Human Cytomegalovirus and Associated Strain-Specific Immunity

Human cytomegalovirus (HCMV), one of the most prevalent viruses across the globe, is a common cause of morbidity and mortality for immunocompromised individuals. Recent clinical observations have demonstrated that mixed strain infections are common and may lead to more severe disease progression. This clinical observation illustrates the complexity of the HCMV genome and emphasizes the importance of taking a population-level view of genotypic evolution. Here we review frequently sampled polymorphisms in the glycoproteins of HCMV, comparing the variable regions, and summarizing their corresponding geographic distributions observed to date. The related strain-specific immunity, including neutralization activity and antigen-specific cellular immunity, is also discussed. Given that these glycoproteins are common targets for vaccine design and anti-viral therapies, this observed genetic variation represents an important resource for future efforts to combat HCMV infections.

Human cytomegalovirus envelope glycoprotein B, H, and N polymorphisms among infants of Shanghai area in China

Human cytomegalovirus (HCMV) is the leading cause of congenital infection and an opportunistic pathogen capable of establishing lifelong latency. In the present study, we aimed to investigate the distribution of glycoprotein B, H, and N in infants of Shanghai and correlate the genotype with active and latent HCMV infection. A total of 129 urine samples were collected between August 2014 and December 2015 from infants under 3 years with HCMV infection. Nested PCR was used to amplify the regions of UL55 (gB), UL75 (gH), and UL73 (gN). Gene sequencing and phylogenetic analyses were used to classify the genotypes. Overall, regarding gB, gB1 (57.27%) was predominant, followed by gB3 (41.82%) and gB4 (0.91%). gH1 (54.33%) was the most prevalent genotype of gH, followed by gH2 (45.67%). Concerning gN, we detected gN1 (17.44%), gN2 (2.33%), gN3a (29.07%), gN3b (8.14%), gN4a (13.95%), gN4b (15.12%), and gN4c (13.95%), among which gN3a was the dominant genotype. All the expected genotypes were present except gB2 in children with active infection: gB1 (56.25%), gB3 (42.5%), gB4 (1.25%), gH1 (58.70%), gH2 (41.30%), gN1 (19.05%), gN2 (3.17%), gN3a (25.40%), gN3b (6.35%), gN4a (15.87%), gN4b (17.46%), and gN4c (12.70%). However, among latent cases, we detected gB1 (60%), gB3 (40%), gH1 (42.86%), gH2 (57.14%), gN1 (13.04%), gN3a (39.13%), gN3b (13.04%), gN4a (8.70%), gN4b (8.70%), and gN4c (17.39%), respectively. gB2, gB4, and gN2 were absent in this group. The results revealed that gB1, gH1, and gN3a were predominant in the infants of Shanghai. gH showed different trends among children with active and latent infection.

Genotypes of glycoprotein B gene among the Indian symptomatic neonates with congenital CMV infection

Background

Cytomegalovirus [CMV] is a causative agent of congenital infection worldwide and often leads to neurological deficits and hearing loss in newborns. Infants born with symptomatic congenital Cytomegalovirus infection [cCMV] are at significant high risk for developing adverse long-term outcomes. In this study, we look into the sequence variability of surface glycoprotein B [gB] encoding region in newborns with symptomatic CMV infection for the first time in Eastern region of India.

Methods

576 suspected newborns from seropositive mothers were subjected to the study and ELISA was used to confirm CMV infection. Different genotypes and their subtypes were determined using multiplex nested-PCR. Viral load of different glycoprotein B [gB] genotypes was measured using RT-PCR. Sequencing and phylogenetic analysis was then performed using Bayesian interference.

Results

The overall frequency of cCMV infection was 18.4%, where 16.0% neonates were symptomatic. Among the different gB genotypes, gB1 had the highest frequency [23.5%] and gB4 showed the lowest occurrence [5.8%]. 23.5% of symptomatic neonates had mixed genotypes of gB, probably indicating matrenal reinfection with CMV strains in Indian population. Significant genotypic clades [gB1-gB2-gB3-gB5] were grouped closely based on gene sequences, but the gB4 sequence was in the outlier region of the phylogenetic tree indicating the genetic polymorphism.

Conclusion

This is the first study on cCMV genotyping and its phylogenetic analysis from Eastern Indian neonatal population. The study holds importance in the assessment of cCMV seroprevalence in global perspective. gB protein can be used as a potential therapeutic target against CMV infection.

Genotyping of Cytomegalovirus from Symptomatic Infected Neonates in Iraq

Among all other viruses, human cytomegalovirus (HCMV) is the most frequent cause of congenital infection worldwide. Strain variation in HCMV may predict severity or outcome of congenital HCMV disease. Previous studies have associated a particular genotype with specific sequelae or more severe illness, but the results were contradictory. There are no previous studies addressing the genotype of HCMV in Iraq. Therefore, the present study is aimed at molecular detection and genotyping of HCMV isolated from symptomatic congenitally/perinatally infected neonates. This prospective study comprised 24 serum samples from symptomatic neonates with congenital/perinatal infection. Viral DNA was extracted from these serum samples; nested polymerase chain reaction was used to amplify the HCMV gB (UL55) gene. Polymerase chain reaction products of the second round of amplification were subjected to direct Sanger sequencing. Bioedit and MEGA5 software (EMBL-EBI, Hinxton, Cambridgeshire, UK) were used for alignment and construction of a phylogenetic tree. Human cytomegalovirus DNA was detected in 23 of 24 samples (95.8%). According to the phylogenetic analysis, three genotypes of the virus were identified; gB1, gB2, and gB3 genotypes. However, the gB4 genotype was not detected. Human cytomegalovirus gB3 was the most frequent genotype: 14 of 24 (58.33%) among symptomatic infected infants, followed by gB1 (6/24; 25%) and gB2 (4/24; 16.67%). A mixed HCMV infection with gB3/gB1 was detected in only one case. Human cytomegalovirus gB3 was the most predominant genotype among symptomatic congenitally/perinatally HCMV-infected neonates. No association was found between B3 genotype and specific clinical presentation. Jaundice was the most common clinical feature among symptomatically infected neonates, followed by hepatosplenomegaly.

Human cytomegalovirus prevalence and distribution of glycoprotein B, O genotypes among hospitalized children with respiratory infections in West China, 2009-2014

OBJECTIVES

Human cytomegalovirus (HCMV) is an important pathogen causing morbidity and mortality in children. HCMV prevalence in children with respiratory infections has not been investigated in West China. Previous studies have suggested that glycoproteins genotypes may be associated with different clinical presentations, but the associations were controversial. The aim of this study was to determine the prevalence of HCMV infection in children with respiratory infections, the distributions of gB, gO genotypes among these isolates and their potential predictive roles for the development of symptoms in children.

METHODS

A total of 1709 respiratory specimens were obtained from hospitalised children with respiratory symptoms from 2009 to 2014 for the confirmation of HCMV infection. Glycoprotein B,O genotyping was carried out by multiplex nested PCR and sequencing.

RESULTS

The overall infection rate was 10.8%, and dominant genotypes were gB1 (74.2%) and gO1 (37.1%). Clinical characteristics differed between infants and children >1 year of age. Infants infected with HCMV had a higher frequency of fever (P < 0.001), cough (P < 0.001), rhinorrhea (P < 0.001), expectoration (P = 0.001) and diarrhoea (P = 0.005). Children <1 year age infected with gB1 had a higher rate of cough (P = 0.0192).

CONCLUSIONS

Infants infected with HCMV had a severe clinical outcome. gB1 may negatively associate with clinical presentations and quality of life in these children. The prevalence of HCMV infection and genotype distribution emphasises the importance of HCMV screening, vaccination and control for transmission.

Distribution of Cytomegalovirus Genotypes among Neonates Born to Infected Mothers in Islamabad, Pakistan

Background

Congenital cytomegalovirus (cCMV) infection contributes to considerable long-term sequelae in neonates and children all over the world. The association between viral genotypes and severity of clinical cytomegalovirus (CMV) infection is yet to be defined. The objective of this study was to find the impact of active CMV infection during pregnancy and the clinical significance of genotypes in neonates with congenital cytomegalovirus infections in Pakistan.

Methods

A total of 409 blood samples from pregnant women seeking health care services at the two antenatal hospitals of Islamabad during January to December 2012 were tested by ELISA and nested-PCR. Pregnant women with active infection (detected as IgM positive, PCR positive or positive on both assays) were followed until delivery, to detect the outcome of overt cCMV infection in neonates. Genetic characterization of CMV strains was performed by sequence analysis of envelope glycoproteins: gB, gN and gH to detect the contributing CMV genotypes.

Results

The seroprevalence of anti-CMV IgG and IgM was 97.5% (399 out of 409) and 12.7% (52 out of 409), respectively, while 20% (82/409) pregnant women were found positive for CMV DNA by PCR. Logistic regression analysis showed a significant association of active infection with parity [OR = 2.56, 95% CI = 1.82–2.62, p = 0.04], febrile illness [OR = 1.84, 95% CI = 1.76–3.65, p = 0.01] and jaundice [OR = 22.5, 95% CI = 4.53–85.02, p = 0.002]. We were able to isolate virus in 41 out of 70 neonates; 36.6% (15 out of 41) of them were symptomatic at birth while 63.4% (26 out of 41) were asymptomatic. The most prominent clinical feature observed in symptomatic neonates was hepatosplenomegaly (26.6%; 4 out of 15). All three genotypes gB, gN and gH were found with the highest frequency of gB1 genotype, found in 75% infants with hepatic damage. Phylogenetic analysis of Pakistani strains showed 96%-100% homology to their prototype strains.

Conclusions

Active CMV infection during pregnancy is a major cause of congenital CMV infection with comparable distribution of all three genotypes: gB, gN and gH in symptomatic and asymptomatic neonates. Our findings emphasize to conduct a comprehensive large scale survey and introduction of country wide routine screening at maternity clinics for early diagnosis of CMV to reduce its associated devastating outcomes.

Combined genetic variants of human cytomegalovirus envelope glycoproteins as congenital infection markers

Background

Human cytomegalovirus (HCMV) is still considered to be the main viral cause of birth defects and long-term neurological and sensory sequelae following congenital infection.

Several Authors sustain a key role of HCMV envelope glycoproteins, such as gB, gN and gO - mainly involved in cell targeting, viral penetration and spread - as putative virulence factors. The genes coding for these glycoproteins possess hypervariable regions, resulting in a number of genetic variants in circulating clinical strains. Considering that the genetic polymorphisms underlying the specific differences between gB, gN and gO genotypes can influence the ability of HCMV to preferentially target specific host cells, it is very likely that they play an important role in defining HCMV infection outcome.

In the present study, we analysed HCMV gB, gN and gO gene polymorphisms in viral strains isolated from paediatric patients with congenital or post-natal infection, to investigate whether specific genetic variants may be associated with congenital infection.

Methods

The restriction fragment polymorphisms of genes coding for HCMV gB (UL55), gN (UL73) and gO (UL74) were investigated by analysing viral DNA extracted from 40 urine samples of as many paediatric patients with congenital or post-natal HCMV infection. Randomly selected samples were subjected to DNA sequencing and phylogenetic analysis. Statistical analysis was performed using Fisher’s exact test to assess the significance of single and combined glycoprotein genotypes frequency distribution. Statistical significance was considered at a P <0.05.

Results

While gB genomic variants were quite homogeneously represented in both paediatric groups, the gN4 genotype significantly prevailed in congenitally infected children (89.5 %) vs post-natally infected children (47.6 %), with a predominance of the gN4c variant (47.4 %). A similar trend was observed for gO3 (52.6 % vs 19 %).

Concerning genotypes association, a statistically significant (P = 0.037) gN4-gO3 combination was found specifically in the congenitally infected group.

Conclusions

The results indicate that the gN4 (mostly the gN4c variant) and gO3 combined genotypes could provide useful markers of congenital infection and represent suitable candidate molecules for prophylactic vaccine preparations.

[The role of virological tests in the diagnosis of cytomegalovirus infection in pregnant women]

INTRODUCTION

The most harmful and most frequent foetal agent is cytomegalovirus. The progress in diagnostic tools and therapeutic opportunities opened new perspectives in the diagnosis and management of foetal cytomegalovirus infection.

AIM

Evaluation of cytomegalovirus virological test results performed during pregnancy between 2007 and 2012.

METHOD

Clinical and virology data were retrospectively analysed.

RESULTS

64.5% of the 956 tested women were serologically protected and 33.3% were susceptible to cytomegalovirus. Recent infection was confirmed in 10 pregnant women, while the infection could not be confirmed or excluded in 3 pregnant women. Six pregnant women were asymptomatic, 5 had typical disease, and 2 had abnormal fetal ultrasound. One fetus aborted, congenital infection was confirmed in 2, and was excluded in one of the four newborns tested.

CONCLUSIONS

The immunity of women to cytomegalovirus reflects high socioeconomic circumstances. Confimatory tests must be done both in women who have cytomegalovirus disease and those who have IgM positive result detected by enzyme (linked) immunoassay. Screening must be done prior to pregnancy. Strict collaboration between professionals of different medical specialties is necessary.

Inflammatory breast cancer: high incidence of detection of mixed human cytomegalovirus genotypes associated with disease pathogenesis

Inflammatory breast cancer (IBC) is a highly metastatic, aggressive, and fatal form of breast cancer. Patients presenting with IBC are characterized by a high number of axillary lymph node metastases. Recently, we found that IBC carcinoma tissues contain significantly higher levels of human cytomegalovirus (HCMV) DNA compared to other breast cancer tissues that may regulate cell signaling pathways. In fact, HCMV pathogenesis and clinical outcome can be statistically associated with multiple HCMV genotypes within IBC. Thus, in the present study, we established the incidence and types of HCMV genotypes present in carcinoma tissues of infected non-IBC versus IBC patients. We also assessed the correlation between detection of mixed genotypes of HCMV and disease progression. Genotyping of HCMV in carcinoma tissues revealed that glycoprotein B (gB)-1 and glycoprotein N (gN)-1 were the most prevalent HCMV genotypes in both non-IBC and IBC patients with no significant difference between patients groups. IBC carcinoma tissues, however, showed statistically significant higher incidence of detection of the gN-3b genotype compared to non-IBC patients. The incidence of detection of mixed genotypes of gB showed that gB-1 + gB-3 was statistically significantly higher in IBC than non-IBC patients. Similarly, the incidence of detection of mixed genotypes of gN showed that gN-1 + gN-3b and gN-3 + gN-4b/c were statistically significant higher in the carcinoma tissues of IBC than non-IBC. Mixed presence of different HCMV genotypes was found to be significantly correlated with the number of metastatic lymph nodes in non-IBC but not in IBC patients. In IBC, detection of mixed HCMV different genotypes significantly correlates with lymphovascular invasion and formation of dermal lymphatic emboli, which was not found in non-IBC patients.

Quantification of cytomegalovirus glycoprotein Bn DNA in hematopoietic stem cell transplant recipients by real-time PCR

Based on sequence variation in the N-terminus of the UL55 gene, which encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into four gBn genotypes. We assessed the distribution of CMV gBn genotypes and the correlation between CMV gBn DNA (detected by real-time PCR) and CMV-positive pp65 cells (identified by immunohistochemical staining) in a cohort of hematopoietic stem cell transplant patients. The distribution of gB genotypes was as follows: gBn1, 60% of patients; gBn2, 13.3%; mixed gBn1 and gBn3 infection, 26.7%; and gBn4 and other mixed infections, 0%. CMV gBn1 was the most common genotype. The detected level of CMV gB DNA correlated well with the number of CMV-positive pp65 cells detected by immunostaining (r = 0.585).

Cytomegalovirus DNA detection in dried blood spots and perilymphatic fluids from pediatric and adult cochlear implant recipients with prelingual deafness

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the leading cause of non-genetic congenital hearing loss. The contribution of congenital CMV to prelingual deafness and the pathophysiology is largely unknown.

OBJECTIVE

(1) To analyze the prevalence of congenital CMV among cochlear implant (CI) recipients with prelingual deafness. (2) To genotype CMV present in dried blood spots (DBS) and in the inner ear years after birth.

STUDY DESIGN

Children and adults with prelingual deafness who received a CI in 2010-2011 were included prospectively. Perilymphatic fluids were collected during CI surgery and, in the pediatric cases, DBS were retrieved for CMV DNA detection. Furthermore, a cohort of children with prelingual deafness who received a CI between 2003 and 2008 were included retrospectively. CMV detection in DBS and perilymph was followed by gB and gH genotyping.

RESULTS

Seventysix pediatric CI recipients were included. Seventy DBS were tested for CMV DNA, resulting in a prevalence of congenital CMV of 14% (10/70). Perilymphatic fluid was available from 29 pediatric CI recipients. One perilymph fluid, of a 21-month old girl with congenital CMV, asymptomatic at birth, was CMV DNA positive. The CMV strain in the perilymph was genotypically identical to the strain present in her DBS (gB1/gH2). Perilymph samples from 21 adult CI recipients were CMV DNA negative.

CONCLUSIONS

Our study stresses the important contribution of congenital CMV among pediatric CI recipients. Furthermore, our genotyping data support the hypothesis that CMV-related hearing loss is associated with ongoing viral replication in the inner ear up to years after birth.

Glycoprotein B genotyping in congenital/perinatal Cytomegalovirus infection in symptomatic infants

BACKGROUND

Molecular epidemiological studies on circulating strains of CMV in cogenital/perinatal infections have not been done earlier in this region.

OBJECTIVE

To study the glycoprotein B genotypes in babies with symptomatic congenital/perinatal CMV infection and to assess the possible influence of genotype on the outcome of the infection.

METHODS

Clinical samples (blood and urine) of symptomatic babies are sent to the Virology Department of NCDC, Delhi for the diagnosis of congenital infections. 375 clinical samples of infants (newborn - 6 months old) were included for the study. Serum samples were subjected to ELISA for detection of IgM antibodies against CMV. DNA isolation and amplification of CMV genomic DNA targeting gB gene fragment by nested PCR, was carried out in the samples. The amplified fragment including the cleavage site was subjected to RFLP using restriction enzymes Rsal and Hinf1. They were also verified by sequencing using Big Dye Terminator chemistry.

RESULTS

75 samples out of 375 tested were confirmed positive for CMV infection by serology and PCR. Both RFLP and sequencing of gB gene fragment showed that gB 1, 2 and 3 genotypes were in circulation. gB 3 was the most prevalent genotype in symptomatic infants. Hepatosplenomegaly was the most common feature in gB-3 genotype of CMV. gB2 congenital CMV infection was more commonly associated with long term sequelae.

Rapid genotyping of cytomegalovirus in dried blood spots by multiplex real-time PCR assays targeting the envelope glycoprotein gB and gH genes

Genotyping of cytomegalovirus (CMV) is useful to examine potential differences in the pathogenicity of strains and to demonstrate coinfection with multiple strains involved in CMV disease in adults and congenitally infected newborns. Studies on genotyping of CMV in dried blood spots (DBS) are rare and have been hampered by the small amount of dried blood available. In this study, two multiplex real-time PCR assays for rapid gB and gH genotyping of CMV in DBS were developed. Validation of the assays with 39 CMV-positive plasma samples of transplant recipients and 21 urine specimens of congenitally infected newborns was successful in genotyping 100% of the samples, with gB1 and gB3 being the most prevalent genotypes. Multiple gB and gH genotypes were detected in 36% and 33% of the plasma samples, respectively. One urine sample from a newborn with symptomatic congenital CMV was positive for gB1 and gB2. DBS of congenitally infected newborns (n = 41) were tested using 9 μl of dried blood, and genotypes were detected in 81% (gB) and 73% (gH) of the samples, with gB3 being the most prevalent genotype. No clear association of specific genotypes with clinical outcome was observed. In conclusion, the CMV gB and gH PCR assays were found to be rapid, sensitive for detecting mixed infections, and suitable for direct usage on DBS. These assays are efficient tools for genotyping of CMV in DBS of congenitally infected newborns.

Distribution of UL144, US28 and UL55 genotypes in Polish newborns with congenital cytomegalovirus infections

Human cytomegalovirus (HCMV) is the most common congenital infection. HCMV strains display genetic variability in different regions. Distribution of HCMV genotypes in the population of congenitally infected newborns from Central Poland and viral load in newborns' blood is described and discussed. HCMV isolates were analysed by sequencing at three sites on the genome: the UL144 tumour necrosis factor-alpha (TNFα)-like receptor gene, the US28 beta-chemokine receptor gene and the UL55 envelope glycoprotein B (gB) gene. The newborns' blood was examined for HCMV DNA with a nested (UL144, UL55) or heminested (US28) polymerase chain reaction, and the genotypes were determined by sequence analysis. HCMV DNA was detectable in 25 out of 55 examined newborns born by HCMV-infected mothers (45.5%). The blood viral load in mother-infant pairs was determined. Most of the newborns had identical virus genotype, gB2 (96%), UL144 B1 (88%) and US28 A2 (84%). These genotypes were detected in all newborns with asymptomatic congenital infection. The occurrence of UL144 B1 or US28 A2 genotypes in the babies examined was significant in comparison to other genotypes (p=0.0002 and p=0.040 respectively). There was no association between specific gB subtypes in all patients groups (p=0.463). There was no correlation between HCMV genotypes and the outcome.

Occurrence of human cytomegalovirus glycoprotein B genotypes in immunocompetent and immunosuppressed Taiwanese patients

OBJECTIVES

To investigate the differences of genotypic distributions among isolates between immunosuppressed and immunocompetent patients in a Taiwanese population.

METHODS

Human cytomegalovirus (HCMV) isolates from 76 patients with adequate chart data were analyzed. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to define gB genotypes which include gB1 to gB4. The clinical data of the 76 patients were retrospectively collected by chart review and classified into an immunosuppressed (n = 32) or immunocompetent (n = 44) group.

RESULTS

Among the 32 immunosuppressed patients, the most commonly identified HCMV genotypes were gB1 (27/32, 84.3%) and gB3 (4/32, 12.5%). 59.1% (26/44) of the immunocompetent patients were infected by gB1 while 38.6% (17/44) of them were infected by gB3. The frequency of gB1 infection in the immunosuppressed group was significantly higher than that in the immunocompetent group (p = 0.025). However, there was no statistically significant difference between gB1 and gB3 distributions by clinical diagnosis within each group.

CONCLUSIONS

Only gB1 and gB3 genotypes were identified in this Taiwanese population. Although there is no significant difference between clinical diagnosis and gB genotyping, gB1 infection is significantly more predominant in immunosuppressed patients.

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.

Human cytomegalovirus glycoprotein genotypes in the genital tract tissue of tubal pregnancy patients

This study investigated human cytomegalovirus (HCMV) glycoprotein genotypes in the genital tract tissue of 125 tubal pregnancy patients. The HCMV glycoprotein-B N-terminus (gBn, 54 - 485 NT), gB endoprotease cleavage site (gBclv, 1284 - 1600 NT) and glycoproteinH (gH, -58 - 213 NT) gene fragments were amplified by nested polymerase chain reaction and sequenced to identify gB and gH genotypes. Of 16 gBn-positive samples, four were gBn1, one was gBn2 and 11 were the gBn3 genotype. Of 13 positive gBclv samples, seven were gBclv1, two were gBclv2 and four were the gBclv3 genotype. Of 20 positive gH samples, 10 were gH1, six were gH2 and four were a combined gH1/gH2 genotype. In 10 of the samples that were positive for the gBn and gBclv genotypes, the gBn and gBclv genotypes were not consistent (four were gBclv1-gBn3). This study showed that: (i) HCMV infection with the gB1 - gB3 glycoprotein genotypes is present in tubal pregnancy; (ii) the gBclv and gBn genotypes are not strictly consistent; and (iii) intragenetic variability within the gB gene due to homologous recombination occurs frequently.

Molecular epidemiology of primary human cytomegalovirus infection in pregnant women and their families

The source of human cytomegalovirus (HCMV) infection was investigated in 29 pregnant women with primary HCMV infection by comparing DNA sequences of UL146, UL144 and a portion of UL55 gene of HCMV strains circulating within each family. Thirteen families were identified in which the pregnant woman, the husband and/or a child were shedding HCMV. In three of these families, both the woman and the husband suffered from a concomitant primary HCMV infection. Phylogenetic analysis of UL146, UL144, and UL55 genes indicated that strains circulating within each family were identical, whereas strains from different families appeared to be distinct. However, identical UL146, UL144, and UL55 DNA sequences were observed sporadically among unrelated strains. A child rather than the husband was the virus source for the great majority of pregnant women. No association was observed between UL144 polymorphisms and intrauterine transmission.

HLA-DQ3 is a probable risk factor for CMV infection in high-risk kidney transplant patients

BACKGROUND

Cytomegalovirus (CMV) infection in transplant patients with special risk factors remains a major hazard. CMV-seronegative recipients with seropositive donors have the highest risk of developing acute CMV disease. We suggest that the HLA-type may influence the occurrence and the severity of primary CMV infection of these recipients and the measurement of the special HLA-types may be useful in the prediction of acute infection.

METHODS

Since 1999 1213 cadaver kidney transplantations have been performed in our clinic. 163 of 1213 recipients were CMV-seronegative (13%) and 129 of them received the kidney from seropositive donors. All 129 patients received CMV infection prophylaxis. Of 129 CMV-seronegative patients 49 developed acute CMV infection (38%) during the first posttransplant year. CMV infection was diagnosed by CMV antigenemia test and serologic measurements (ELISA). The particular HLA-genotypes of the recipients were studied before the transplantation. The occurrence and the severity of CMV infection was investigated in association with HLA-types.

RESULTS

We found different acute CMV infection distribution in the careers and non-careers of investigated HLA-types: HLA-A2, HLA-B12, HLA-Cw7, HLA-DR6 and HLA-DR11, but the differences were not significant in these HLA-types (P = 0.26, P = 0.37, P = 0.83, P = 0.07 and P = 0.37). While investigating HLA-DQ3, we found that of 68 DQ3-positive patients 32 (47%), of 61 DQ3-negative patients 17 (28%) had acute CMV infection and this difference was found to be significant. This result was confirmed by univariate and multivariate Cox Regression (P = 0.001) and the appropriate significance level was considered by Bonferroni correction.

CONCLUSIONS

HLA-DQ3 was found to be an independent predictor of CMV infection. Our data suggest that patients positive for HLA-DQ3 are more susceptible to CMV infection than a comparable group of patients negative for HLA-DQ3. This result was not due to rejection and/or treatment for rejection and was not influenced by induction therapy. Although we found more symptomatic infections among DQ3+ patients the difference was not significant (P = 0.19). Comparing the gender proportion among all 1213 kidney recipients and among CMV-seronegative recipients we found that the proportion of males is significantly higher among CMV-seronegative recipients (P < 0.001).

Human cytomegalovirus glycoprotein B genotypes in Brazilian mothers and their congenitally infected infants

A case-control study design was used in order to compare the distribution of human cytomegalovirus (HCMV) glycoprotein B (gB) genotypes in 48 mothers of 49 congenitally infected infants with that observed in 144 mothers of 146 uninfected infants to study genetic variation of HCMV strains and maternal-fetal transmission. Congenital infection with HCMV was characterized by DNA detection and virus isolation from two urine or saliva samples collected prior to the third week of life. Genotyping of HCMV was carried out by a polymerase chain reaction-restriction fragment length polymorphism analysis of the variable region of the gB gene, testing for four genotypes. Genotype frequency was similar among the 28 non-transmitting mothers who were shedding virus (gB1: 25%; gB2: 28.6%; gB3: 42.8%; gB4: 0%), the 37 transmitting mothers (gB1: 21.6%; gB2: 46%; gB3: 27%; gB4: 0%), and the 49 infected infants (gB1: 39%; gB2: 37%; gB3: 24%; gB4: 0%). The same genotype was detected at different body sites (urine, saliva, and blood) of each infected newborn and in the respective mother (breast milk, urine, and saliva). Co-infection with multiple genotypes was observed in the immediate postpartum period in two mothers of infected infants (5.4%) and one non-transmitting mother (3.6%). The gB genotype was not correlated with intrauterine HCMV transmission. The genotype distribution found reflects the overall frequency of wild strains circulating in this geographic region. A single genotype is responsible for congenital HCMV infection. Co-infection with more than one strain, as characterized by gB genotype, was infrequent in women who were presumably immunocompetent.

Distinct genotypic distribution of cytomegalovirus (CMV) envelope glycoprotein B (gB) in a Cuban cohort of patients with different CMV diseases

To investigate the association between human CMV glycoprotein B (gB) genotypes and CMV disease, we retrospectively analysed 73 biological samples from 56 Cuban patients with different CMV-related diseases using a multiplex nested PCR for detection of the reported 5 CMV gB genotypes. All 4 main genotypes 1 to 4 were found in the clinical samples while no genotype 5 was detected. Among the individuals analysed, genotype gB-2 was the most prevalent (38%) followed by gB-1 (30%) and mixed infections (16%) being mainly detected among immunosuppressed patients (7 out of 9), although there was no association between mixed infections and CMV rejection in transplant recipients. Genotype gB-4 was the least frequent (5 patients), which was almost exclusively detected in mixed infections (4 out of 5, p<0.0001). Genotype gB-1 was more frequently detected in AIDS patients (47%) although it was not statistically significant, while 68% of transplant patients showed mixed infections (p<0.05). This study represents the first report of human CMV gB genotypes in Cuban patients; however, the study is limited by the small number patients, thus making it difficult to draw firm conclusions about the distribution of CMV genotypes in Cuba. Nevertheless, this preliminary report has allowed us to identify that the main 4 CMV genotypes are present in the Cuban population, with genotypes 2 and 1 being the most frequent strains.

Human Cytomegalovirus Glycoprotein B Genotype Correlates with Different Symptoms of Infected Infants

OBJECTIVES

Human cytomegalovirus (HCMV) is the pathogen of cytomegalic inclusion disease of infants. HCMV strains can be classified into four genotypes of glycoprotein B (gB). There are limited data concerning links between clinical symptoms and HCMV genotypes. The aims of the present study were to determine the genotype of HCMV isolates from pediatric patients who have different symptoms on the assumption that the gB genotype may influence the outcomes of congenital and prenatal HCMV infection.

METHODS

The gB types of HCMV were determined in urine specimens from 208 infected infants using nested polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

These data showed the dominance of the gB1 genotype in HCMV-infected infants. The distributions of HCMV gB genotypes in jaundice, malformation, and pneumonia patients are different.

CONCLUSION

There are some relationships between the gB genotypes and the different symptoms of HCMV infection. The four gB genotypes of HCMV may have different clinical outcomes in infected infants.

Sequence variability of human cytomegalovirus UL146 and UL147 genes in low-passage clinical isolates

OBJECTIVES

Human cytomegalovirus (HCMV) infects a number of organs and cell types in vivo. The different symptoms and tissue tropisms of HCMV infection perhaps result from the genetic polymorphism. A new region of DNA containing at least 19 open reading frames (ORFs - denoted UL133-151) was found in the low-passage HCMV clinical strain Toledo and several other low-passage clinical isolates, but not present in the HCMV laboratory strain AD169. Two of these genes, UL146 and UL147, encode proteins with sequence characteristics of CXC (alpha) chemokines, suggesting that they might influence the behavior of neutrophils during infection. This research was to study the sequence variability of UL146 and UL147 ORFs in HCMV clinical isolates and examine the possible associations between gene variability and the outcome of HCMV infection.

METHODS

UL146 and UL147 genes from strains obtained from suspected congenitally HCMV-infected infants were PCR amplified and sequenced.

RESULTS

High variability was found in UL146 and UL147 gene among HCMV clinical strains. However, the alpha chemokine motif in UL146 and UL147 genes was conserved in almost all sequences. According to the phylogenetic analysis, all sequences of UL146 in clinical isolates could be divided into three groups. All strains from congenital megacolon infants existed in G2A only, and all from asymptomatic infants existed in G2B peculiarly.

CONCLUSIONS

Sequence variability among HCMV clinical strains may affect the ability of UL146 and UL147 to attract human neutrophils and influence viral dissemination. No obvious linkage was observed between UL146 polymorphisms and outcome of suspected congenital HCMV infection.

Human cytomegalovirus genetic variability in strains isolated from Japanese children during 1983-2003

The genetic variability of 74 human cytomegalovirus (HCMV) clinical isolates from 60 Japanese infants and children during 1983-2003 was investigated, and the relevance to their clinical course was studied. The patients consisted of 10 asymptomatic congenitally infected babies, 45 infected perinatally or postnatally resulting in HCMV mononucleosis/hepatitis and 5 immunocompromised hosts. The hypervariable region of the HCMV genome, that is the a sequence and UL144 region was analyzed using the polymerase chain reaction (PCR) and unrooted phylogenetic trees. HCMV glycoprotein B (gB) polymorphism was also studied. Unrooted phylogenetic trees of a sequence and UL144 allowed the isolates to be grouped to 5 and 3 clades, respectively. Three gB genotypes were also determined. However, there was no correlation between specific genotypes of these three genes and clinical forms, except for congenital infection which fell into one of three clades of the UL144 gene. In addition, the variability of the three genes had no correlation with each other. This implies that study of a single gene is insufficient for investigating the molecular epidemiology of HCMV. This study provides basic data on the genetic variability of HCMV in an Asian population and should help to determine the strains for vaccine candidates.

Cytomegalovirus (CMV) glycoprotein B genotype and CMV DNA load in the amniotic fluid of infected fetuses

OBJECTIVE

To assess the value of both cytomegalovirus (CMV) DNA quantification in amniotic fluid (AF) and CMV glycoprotein B (gB) genotype as prognostic factors in CMV congenital infection.

METHODS

Quantification of CMV DNA was performed prospectively by real-time PCR and gB genotypes were analysed by gene sequencing analysis in the amniotic fluid of 42 fetuses infected by CMV. These were correlated with clinical data on fetal anomalies and outcome.

RESULTS

The proportion of severely symptomatic fetuses was similar in each gB genotype group. Median CMV DNA load was higher in the group of symptomatic fetuses but this difference was not significant and high and low viral loads were found in both groups.

CONCLUSION

Neither gB genotype nor CMV DNA load in AF correlate with the severity of CMV congenital infection and these markers are unlikely to prove useful for the management of congenital infection.

Genomic variants among human cytomegalovirus (HCMV) clinical isolates: the glycoprotein n (gN) paradigm

Human cytomegalovirus (HCMV) clinical isolates display genetic polymorphisms, which are supposed to be implicated in strain-specific tissue tropism and HCMV-induced immunopathogenesis. One highly variable gene is ORF UL73, encoding for the envelope glycoprotein gN, which displays both a structural and an immunologic role as a component of the high-molecular weight complex gC-II. UL73 showed clustered polymorphisms, which originate four distinct genomic variants, denoted gN-1, gN-2, gN-3, and gN-4. This review reports the main features of gN genotypes and their potential implications on HCMV biologic properties. The clinical impact of gN variants is also discussed. This overview on gN clustered polymorphisms should be useful as a prototype model for a better understanding of the biologic and clinical relevance of HCMV clinical isolates genetic variability.

[Genetic polymorphism of cytomegalovirus strains responsible of congenital infections]

OBJECTIVES

Congenital Cytomegalovirus (CMV) infection is the main cause of neurological handicap in young children. The objective for studying genetic polymorphism of strains responsible for congenital infection is to identify CMV strains or groups of strains which would be more frequent in this context and/or which would be responsible for more severe congenital infection.

METHODS

In this paper, we report and analyze the literature concerning the genetic polymorphism of CMV strains responsible of congenital infection, in the genes coding for the envelop protein B and the non structural UL144 protein and in the CMV short tandem repeats.

RESULTS AND CONCLUSION

All UL144 and gB genotypes can be vertically transmitted from mothers to fetuses, none of these studies has shown any link between the genotypes and the severity of congenital disease. Moreover, no link between short tandem repeats polymorphism and severity of congenital disease has been demonstrated. However, short tandem repeats analysis may be a powerful tool to study the epidemiology of CMV congenital infections.

Mother-to-fetus transmission of cytomegalovirus. A review

Congenital human cytomegalovirus (CMV) infection is the leading infectious cause of mental retardation, sensorineural deafness and visual impairment. It is mainly related to a primary maternal infection. The placenta should be considered the most important site of both the protection of the fetus from CMV infection and the transmission of CMV from mother to fetus. The control of the passage of CMV across the placenta probably involves a cascade of regulatory events. Roles are played by factors relating to the host immune-selective pressures, such as local cytokines and maternal CMV-specific neutralizing antibodies. The presence of other pathogens at the maternal-fetal interface also influences the outcome of CMV infection. Further investigations are needed in which clinical CMV strains are applied in in vitro studies to unravel the molecular mechanism of the intrauterine transmission of CMV and to elucidate the complex regulation that leads to prevention of the in utero transmission of CMV in vivo.

Genetic polymorphisms among human cytomegalovirus (HCMV) wild-type strains

Human cytomegalovirus (HCMV) clinical isolates display genetic polymorphisms in multiple genes. Some authors have suggested that those polymorphisms may be implicated in HCMV-induced immunopathogenesis, as well as in strain-specific behaviours, such as tissue-tropism and ability to establish persistent or latent infections. This review summarises the features of the main clustered HCMV polymorphic open reading frames and also briefly cites other variable loci within the viral genome. The implications of gene polymorphisms are discussed in terms of potentially advantageous higher fitness obtained by the strain, but also taking into account that the published data are often speculative. The last section of this review summarises and critically analyses the main literature reports about the linkage of strain specific genotypes with clinical manifestations of HCMV disease in different patient populations affected by severe cytomegalovirus infections, namely immunocompromised subjects and congenitally infected newborns.

Human cytomegalovirus UL144 gene polymorphisms in congenital infections

The human cytomegalovirus (HCMV) UL144 gene is a tumor necrosis factor-like receptor with the potential to affect HCMV virulence. HCMV strains display genetic variability in the UL144 region, and the analysis of a potential link between UL144 gene polymorphisms and disease severity has scarcely been studied. However, a correlation between the UL144 genotype and congenital-disease outcome has been reported in one previous study, with the observation that all asymptomatic infants had a single UL144 genotype. In order to confirm or refute this finding, we determined the UL144 polymorphisms of HCMV strains recovered from the amniotic fluids of 38 infected fetuses and compared them to HCMV strains obtained from 30 viremic adult controls. The UL144 sequences were distributed among five genotypes (A, B, C, AC, and AB), as previously described. We observed similar percentages of the three major genotypes A (37%), B (33%), and C (27%) in our population. The UL144 genotype distributions were similar among the group of infected adults and the group of infected fetuses and among symptomatic and asymptomatic fetuses (P < 0.05). In our series, all five UL144 genotypes could be vertically transmitted from mothers to fetuses, and all could cause symptomatic congenital infection. We concluded that determination of UL144 polymorphisms in cases of congenital infection is not relevant, since it is unlikely to help predict the outcome of the infection.

Determination of human cytomegalovirus genetic diversity in different patient populations in Costa Rica

Seroprevalence of HCMV in Costa Rica is greater than 95% in adults; primary infections occur early in life and is the most frequent congenital infection in newborns. The objectives of this study were to determine the genetic variability and genotypes of HCMV gB gene in Costa Rica. Samples were collected from alcoholics, pregnant women, blood donors, AIDS patients, hematology-oncology (HO) children and HCMV isolates from neonates with cytomegalic inclusion disease. A semi-nested PCR system was used to obtain a product of 293-296 bp of the gB gene to be analyzed by Single Stranded Conformational Polymorphism (SSCP) and sequencing to determine the genetic polymorphic pattern and genotypes, respectively. AIDS patients showed the highest polymorphic diversity with 14 different patterns while fifty-six percent of HO children samples showed the same polymorphic pattern, suggesting in this group a possible nosocomial infection. In neonates three genotypes (gB1, gB2 and gB3), were determined while AIDS patients and blood donors only showed one (gB2). Of all samples analyzed only genotypes gB1, 2 and 3 were determined, genotype gB2 was the most frequent (73%) and mixed infections were not detected. The results of the study indicate that SSCP could be an important tool to detect HCMV intra-hospital infections and suggests a need to include additional study populations to better determine the genotype diversity and prevalence.

Onset and duration of cytomegalovirus immediate early 1 mRNA expression in the blood of renal transplant recipients

Human cytomegalovirus (CMV) messenger (m) RNA expression in circulating leukocytes reflects directly viral activity in the human host. In this study, sixty-nine patients were monitored prospectively for CMV infection and mRNA expression during the first year after renal transplantation. Of the 69 recipients, 58 (84%) recipients were positive for CMV immediate early 1 (IE1) mRNA as detected by nucleic acid sequence-based amplification. The median onset of IE1 expression started at day 22 after transplantation and continued for a median duration of 82 days. IE1 mRNA expression started significantly earlier in recipients who developed an active CMV infection (P = 0.001) and in mycophenolate mofetil (MMF) treated recipients (P = 0.002). The duration of IE1 mRNA expression was significantly longer in recipients that had previously an early onset of IE1 mRNA expression (P = 0.001) and in recipients with active CMV infection (P = 0.007). Remarkably, longer prednisolone intake was correlated with a significantly (P = 0.02) shorter duration of IE1 expression compared to a longer duration of IE1 expression in recipients with only a short prednisolone intake. In recipients infected with glycoprotein B (gB) type 1 CMV strains, the duration of IE1 expression was significantly (P = 0.04) shorter compared to recipients infected with non-gB type 1 CMV strains (64 days vs. 150 days). The study indicates that multiple factors play a role in the onset and/or duration of CMV IE1 mRNA expression, for example, MMF treatment, prednisolone intake, and gB type of the specific CMV strain. The clinical significance of these correlations remains to be studied in more detail.