Role of human cytomegalovirus genotype polymorphisms in AIDS patients with cytomegalovirus retinitis

Cytomegalovirus Glycoprotein B Genotype in Patients with Anterior Segment Infection

(1) The glycoprotein B (gB) on the viral envelope, encoded by the most widely characterised polymorphic gene, gpUL55, is responsible for cytomegalovirus (CMV) entry into the host and could serve as a potential marker of pathogenicity. The aim of the present study is to investigate the distribution of the CMV gB genotype in anterior segment infection in Taiwan and its correlation with clinical manifestations and outcomes. (2) Fifty-seven patients with CMV anterior segment infection were identified according to clinical features and positivity for CMV DNA in aqueous humour samples. CMV gB genotyping was performed through polymerase chain reaction assays. Patients’ medical records were retrospectively reviewed. (3) Among the 57 aqueous humour samples tested for gB, 40 (70.28%) had multiple gB genotypes, and only 17 (29.82%) had a single gB genotype. Compared with single-genotype infection, multiple-genotype infection was correlated with higher CMV loads (p < 0.001) but not correlated with outcome. A higher proportion of patients with the gB3 genotype had received filtering surgery before antiviral treatment than those without the gB3 genotype (p = 0.046). (4) Multiple-genotype infection was highly prevalent in CMV anterior segment infection in Taiwan, and gB1 and gB3 were predominant. Multiple-genotype infection was correlated with higher CMV loads but not with specific clinical manifestations or prognostic outcomes. The gB3 genotype may be correlated with poor intraocular pressure control.

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.

Polymorphisms of the cytomegalovirus glycoprotein B genotype in patients with Posner-Schlossman syndrome

Aims

The aim of this observational study was to report the distribution of glycoprotein B (gB) genotypes in the eyes of cytomegalovirus (CMV) positive patients with Posner-Schlossman syndrome (PSS), and to investigate their clinical characteristics and outcomes.

Methods

We collected aqueous humour samples from 165 patients clinically diagnosed with PSS between 2017 and 2019. PCR was performed to analyse the CMV DNA and identify the gB genotypes in the samples. Clinical characteristics and responses to antiviral treatment were compared among patients with different gB genotypes.

Results

CMV DNA was detected in 94 (56.97%) of the 165 aqueous humour specimens analysed. Owing to the quantity requirement for CMV gB genotype analysis, results could be obtained from only 14 specimens. CMV gB type 1 was detected in 11 samples (78.6%), whereas CMV gB type 3 was detected in three samples (21.4%). No other gB genotypes or mixed genotypes were detected. Overall, 9.1% (1/11) of the patients in the gB type 1 group and 66.7% (2/3) of the patients in the gB type 3 group had bilateral attacks (p=0.093). The concentration of anti-CMV immunoglobulin G (IgG) in the type 1 group was 0.94±0.79 s/co (ratio of aqueous humour CMV IgG/serum CMV IgG to aqueous humour albumin concentration/serum albumin concentration), whereas that in the type 3 group was 0.67±0.71 s/co.

Conclusion

Genotype 1 was the most prevalent genotype in the aqueous humour of CMV-infected patients with PSS. Bilateral attack was predominant among patients with gB genotype 3. CMV gB gene may be related to the pathogenicity of CMV virus strain in patients with PSS.

Clinical Features and Diagnosis of Anterior Segment Inflammation Related to Cytomegalovirus in Immunocompetent African, Asian, and Caucasian Patients

Objective: To report the clinical features and treatment outcomes in immunocompetent patients with anterior segment inflammation (ASI) related to human cytomegalovirus (HCMV) depending on their ethnic origin.Material and Methods: Multicenter retrospective study of 38 patients with at least one test, either HCMV-positive PCR or GWc.Results: Features of Posner-Schlossman syndrome were observed in 50% of the eyes, Fuchs heterochromic iridocyclitis in 13% of the eyes, chronic nonspecific anterior uveitis in 21% of the eyes, and corneal endotheliitis in 18% of the eyes. PCR and GWc were positive for HCMV in 50% and 96.2% of the eyes, respectively. Glaucoma was diagnosed in 50% of eyes. Treatment was oral valganciclovir in about half of the patients. Other treatments were intravenous ganciclovir and/or ganciclovir topical ointment and/or intravitreal ganciclovir.Conclusions: No obvious association of specific clinical features with individual ethnicity could be identified. We found a high rate of glaucoma in all ethnic groups. There was a delay in diagnosis and specific treatment of HCMV in most patients.

The Thrombopoietin Receptor Agonist Eltrombopag Inhibits Human Cytomegalovirus Replication Via Iron Chelation

The thrombopoietin receptor agonist eltrombopag was successfully used against human cytomegalovirus (HCMV)-associated thrombocytopenia refractory to immunomodulatory and antiviral drugs. These effects were ascribed to the effects of eltrombopag on megakaryocytes. Here, we tested whether eltrombopag may also exert direct antiviral effects. Therapeutic eltrombopag concentrations inhibited HCMV replication in human fibroblasts and adult mesenchymal stem cells infected with six different virus strains and drug-resistant clinical isolates. Eltrombopag also synergistically increased the anti-HCMV activity of the mainstay drug ganciclovir. Time-of-addition experiments suggested that eltrombopag interfered with HCMV replication after virus entry. Eltrombopag was effective in thrombopoietin receptor-negative cells, and the addition of Fe³⁺ prevented the anti-HCMV effects, indicating that it inhibits HCMV replication via iron chelation. This may be of particular interest for the treatment of cytopenias after hematopoietic stem cell transplantation, as HCMV reactivation is a major reason for transplantation failure. Since therapeutic eltrombopag concentrations are effective against drug-resistant viruses, and synergistically increase the effects of ganciclovir, eltrombopag is also a drug-repurposing candidate for the treatment of therapy-refractory HCMV disease.

Distribution of the CMV glycoprotein gH/gL/gO and gH/gL/pUL128/pUL130/pUL131A complex variants and associated clinical manifestations in infants infected congenitally or postnatally

Human cytomegalovirus (CMV) is a major cause of morbidity in fetuses following intrauterine infection. The glycoprotein (g) envelope trimeric gH/gL/gO and pentameric gH/gL/pUL128/pUL130/pUL131A complexes are required for CMV entry into fibroblasts and endothelial/epithelial cells, respectively, and both are targets for neutralizing antibodies. The role of sequence variability among viral strains in the outcome of congenital CMV infection is controversial. Variation in the CMV UL75 gene encoding glycoprotein H (gH), the UL115 (gL), the UL74 (gO), and the UL128 locus (UL128L) encoding three structural proteins (pUL128, pUL130, and pUL131A) was determined in 82 newborns with congenital CMV infection and 113 infants with postnatal or unproven congenital CMV infection. Genotyping was performed by sequencing analysis of PCR-amplified fragments and the PCR-restriction fragment length polymorphism (RFLP) method, and the viral load was measured by quantitative real-time PCR. The obtained results demonstrated that (1) different CMV variants and mixed CMV infections can be detected in newborns infected congenitally; (2) the gH1 genotype, UL130 variant 6, and UL131A variant 1 were associated with some signs/symptoms within cohort of pediatric patients, mainly consisting of infants with symptomatic CMV infection. The results revealed that pUL130, pUL131A, and gH polymorphisms seemed to be associated with the outcome of CMV infection in infants.

Cytomegalovirus keratitis

PURPOSE OF REVIEW

Cytomegalovirus (CMV) keratitis, albeit an uncommon manifestation of this ubiquitous pathogen, can lead to devastating ocular morbidity. Timely diagnosis and appropriate treatment are also unfortunately uncommon. The purpose of this review is to discuss recently published literature regarding the epidemiology, pathophysiology, diagnosis, and therapy of CMV keratitis.

RECENT FINDINGS

Classic clinical presentations of CMV keratitis are known; however, current investigations further elucidate characteristics of typical versus atypical disease. Ongoing research stems beyond utilizing PCR analysis towards targeted diagnostic studies with advanced imaging modalities as well as modern genotyping techniques. Strong clinical acumen combined with appropriate handling of these modern technologies are proving invaluable for rapid diagnosis and treatment of this virulent pathogen.

SUMMARY

The current recommended treatment for CMV keratitis is systemic ganciclovir. Astute clinicians must consider this diagnosis in any patient with keratitis, anterior uveitis, and intraocular hypertension. Novel diagnostic techniques should be combined with clinical exam findings to accurately and efficiently diagnose, treat, and monitor progression.

Distribution of cytomegalovirus genotypes among ulcerative colitis patients in Okinawa, Japan

BACKGROUND/AIMS

To determine the prevalence of glycoprotein B (gB), glycoprotein N (gN), and glycoprotein H (gH) genotypes of human cytomegalovirus (HCMV) superimposed on ulcerative colitis (UC) patients in Japan.

METHODS

Four archived stool samples and 7-archived extracted DNA from stool samples of 11 UC patients with positive multiplex polymerase chain reaction (PCR) results for HCMV were used UL55 gene encoding gB, UL73 gene encoding gN, and UL75 gene encoding gH were identified by PCR. Genotypes of gB and glycoprotein N were determined by sequencing.

RESULTS

Among 11 samples, 8 samples were amplified through PCR. gB, gN, and gH genotypes were successfully detected in 3 of 8 (37.5%), 4 of 8 (50%), and 8 of 8 (100%), respectively. The distribution of gB and gN genotypes analyzed through phylogenetic analysis were as follows: gB1 (2/3, 66.7%), gB3 (1/3, 33.3%), gN3a (2/4, 50%), and gN3b (2/4, 50%). Other gB genotypes (gB2 and gB4) and gN genotypes (gN1, gN2, and gN4) were not detected in this study. Out of successfully amplified 8 samples of gH genotype, gH1 and gH2 were distributed in 12.5% and 75% samples, respectively. Only 1 sample revealed mixed infection of gH genotype. The distribution of gH1 and gH2 differed significantly (1:6, P<0.05) in UC patients. The distribution of single gH genotype also revealed significant difference in UC patients who were treated with immunosuppressive drug (P<0.05).

CONCLUSIONS

In this study, gB1, gN3, and gH2 gene were determined as the most frequently observed genotypes in UC patients, which suggest that there might be an association between these genotypes of HCMV and UC.

Positively Selected Sites at HCMV gB Furin Processing Region and Their Effects in Cleavage Efficiency

Human cytomegalovirus is a ubiquitous infectious agent that affects mainly immunosuppressed, fetuses, and newborns. The virus has several polymorphic regions, in particular in the envelope glycoproteins. The UL55 gene encodes the glycoprotein B that has a variable region, containing a furin cleavage site and according to the variability different genotypes are characterized. Here we investigated variability and existence of selective pressure on the UL55 variable region containing the furin cleavage site in 213 clinical sequences from patients worldwide. We showed the occurrence of positive selective pressure on gB codons 461 and 462, near the furin cleavage site. Cleavage analysis of synthesized peptides demonstrated that most mutations confer better cleavage by furin, suggesting that evolution is acting in order to increase the efficiency cleavage and supporting the hypothesis that gB processing is important in the host. We also demonstrated that peptides containing sequences, that characterize genotypes gB2 and 3, are differentially cleaved by furin. Our data demonstrate for the first time that variability in the cleavage site is related to degree of gB processing by furin.

Human cytomegalovirus glycoprotein polymorphisms and increasing viral load in AIDS patients

BACKGROUND

Multiple strains infection of human cytomegalovirus (HCMV) was found to be correlated with increased viral load in immunodeficient patients. However, the pathogenic mechanism underlying this correlation remains unclear. To evaluate genetic polymorphisms of HCMV glycoprotein and their potential role in its viral load, HCMV glycoprotein B, N, and O (gB, gN and gO) genotypes was studied in the population of HCMV infected acquired immune deficiency syndrome (AIDS) patients. The association between glycoprotein polymorphisms and HCMV viral load was analyzed.

METHODS

The genetic polymorphisms of glycoprotein from sera of 60 HCMV infected AIDS patients was investigated by multiplex nested PCR and sequencing. HCMV viral load was evaluated by quantitative PCR.

RESULTS

gB1, gO1a, and gN4a were the predominant glycoprotein genotypes in HCMV infected AIDS patients and composed 86.96%, 78.8%, and 49.2%, respectively. Only gN4a genotype infection significantly increased viral load (P = 0.048). 71% (43/60) of HCMV infected AIDS patients were found to carry multiple HCMV strains infection. A novel potential linkage of gO1a/gN4a was identified from multiple HCMV infected patients. It was the most frequent occurrence, accounted for 51.5% in 33 patients with gO and gN genotypes infection. Furthermore, the gO1a/gN4a linkage was correlated to an increased viral load (P = 0.020).

CONCLUSION

The gN4a correlates to higher level HCMV load in AIDS patients. Interestingly, a novel gO1a/gN4a linkage is identified from the patients with multiple HCMV strains infection and is also associated with an increased viral load. Therefore, the pathogenic mechanism underlying glycoprotein polymorphisms and interaction of variants should be analyzed further.

Modulation of the Host Environment by Human Cytomegalovirus with Viral Interleukin 10 in Peripheral Blood

Background

Human cytomegalovirus (HCMV) is a herpesvirus with both lytic and latent life cycles. Human cytomegalovirus encodes 2 viral cytokines that are orthologs of human cellular interleukin 10 (cIL-10). Both cytomegalovirus interleukin 10 (cmvIL-10) and Latency-associated cytomegalovirus interleukin 10 (LAcmvIL-10) (collectively vIL-10) are expressed during lytic infection and cause immunosuppressive effects that impede virus clearance. LAcmvIL-10 is also expressed during latent infection of myeloid progenitor cells and monocytes and facilitates persistence. Here, we investigated whether vIL-10 could be detected during natural infection.

Methods

Plasma from healthy blood donors was tested by enzyme-linked immunosorbent assay for anti-HCMV immunoglobulin G and immunoglobulin M and for cIL-10 and vIL-10 levels using a novel vIL-10 assay that detects cmvIL-10 and LAcmvIL-10, with no cross-reactivity to cIL-10.

Results

vIL-10 was evident in HCMV+ donors (n = 19 of 26), at levels ranging 31-547 pg/mL. By comparison, cIL-10 was detected at lower levels ranging 3-69 pg/mL. There was a strong correlation between vIL-10 and cIL-10 levels (P = .01). Antibodies against vIL-10 were also detected and neutralized vIL-10 activity.

Conclusions

vIL-10 was detected in peripheral blood of healthy blood donors. These findings suggest that vIL-10 may play a key role in sensing or modifying the host environment during latency and, therefore, may be a potential target for intervention strategies.

Refining human T-cell immunotherapy of cytomegalovirus disease: a mouse model with 'humanized' antigen presentation as a new preclinical study tool

With the cover headline 'T cells on the attack,' the journal Science celebrated individualized cancer immunotherapy by adoptive transfer of T cells as the 'Breakthrough of the Year' 2013 (J. Couzin-Frankel in Science 342:1432-1433, 2013). It is less well recognized and appreciated that individualized T cell immunotherapy of cytomegalovirus (CMV) infection is approaching clinical application for preventing CMV organ manifestations, interstitial CMV pneumonia in particular. This coincident medical development is particularly interesting as reactivated CMV infection is a major viral complication in the state of transient immunodeficiency after the therapy of hematopoietic malignancies by hematopoietic cell transplantation (HCT). It may thus be attractive to combine T cell immunotherapy of 'minimal residual disease/leukemia (MRD)' and CMV-specific T cell immunotherapy to combat both risks in HCT recipients simultaneously, and ideally with T cells derived from the respective HLA-matched HCT donor. Although clinical trials of human CMV-specific T cell immunotherapy were promising in that the incidence of virus reactivation and disease was found to be reduced with statistical significance, animal models are still instrumental for providing 'proof of concept' by directly documenting the prevention of viral multiple-organ histopathology and organ failure under controlled conditions of the absence versus presence of the therapy, which obviously is not feasible in an individual human patient. Further, animal models can make predictions regarding parameters that determine the efficacy of T cell immunotherapy for improved study design in clinical investigations, and they allow for manipulating host and virus genetics. The latter is of particular value as it opens the possibility for epitope specificity controls that are inherently missing in clinical trials. Here, we review a recently developed new mouse model that is more approximated to human CMV-specific T cell immunotherapy by 'humanizing' antigen presentation using antigenically chimeric CMV and HLA-transgenic mice to allow for an in vivo testing of the antiviral function of human CMV-specific T cells. As an important new message, this model predicts that T cell immunotherapy is most efficient if CD4 T cells are equipped with a transduced TCR directed against an epitope presented by MHC/HLA class-I for local delivery of 'cognate' help to CD8 effector T cells at infected MHC/HLA class-II-negative host tissue cells.

Characterising variation in five genetic loci of cytomegalovirus during treatment for congenital infection

Cytomegalovirus (CMV) is the most common congenital infection in humans and a leading cause of sensorineural hearing loss. Ganciclovir (6 mg/kg twice daily for 42 days) has been shown to reduce hearing deterioration and is used in clinical practice. Vaccines and passive administration of antibody are being evaluated in randomized controlled trials in allograft candidates, women of childbearing age, and pregnant women with primary CMV infection. To help define genetic variation in each of the targets of these therapeutic interventions, we amplified and sequenced genes UL97 (site utilised for ganciclovir phosphorylation), UL55 (glycoprotein B (gB) vaccine target) and UL128, UL130, and UL131a (specific monoclonal antibody targets). Serial blood, saliva, and urine samples (total 120) obtained from nine infants with symptomatic congenital CMV treated with 42 days' ganciclovir were analyzed. All samples tested were UL97 wild type at baseline and none developed mutations during treatment, showing no selection of resistance. The prevalences of UL55 genotypes were 28% gB1, 22% gB2, 1% gB3, and mixed in 20% samples. No mutations were noted in UL128-131a. Phylogenetic tree analysis showed that sequences with variations were found in multiple body sites of individual patients, so there was no evidence of body site compartmentalization of particular strains of CMV. The significance of these results for changes in diagnostic practices and therapeutic interventions against CMV are discussed. J. Med. Virol. 89:502-507, 2017. © 2016 Wiley Periodicals, Inc.

Prospects of a vaccine for the prevention of congenital cytomegalovirus disease

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

Polymorphisms in cytomegalovirus genotype in immunocompetent patients with corneal endotheliitis or iridocyclitis

Cytomegalovirus (CMV) that caused corneal endotheliitis and iridocyclitis in immunocompetent patients was genotyped. The gB type1 was detected in seven endotheliitis samples (77.8%) and five iridocyclitis samples (100%), and the gB type 3 was detected in two endotheliitis samples (22.2%). The UL144 type 1 was found in five endotheliitis samples (45.5%) and five iridocyclitis samples (83.3%). The UL144 type 2 was found in two endotheliitis samples (18.2%) and one iridocyclitis sample (16.7%). The gB type 1 was predominant in endotheliitis and iridocyclitis, and the CMV genotypes in eyes with endotheliitis and iridocyclitis were similar.

Long ncRNAs expressed during human cytomegalovirus infections

ABSTRACT: 

Human cytomegalovirus (HCMV) has a tremendous coding capacity within its dsDNA genome that has allowed it to coevolve with its host. Transcription of the virus genome is not limited to protein-coding genes; in fact, most of the transcription from the HCMV genome during lytic replication generates viral ncRNAs that are not translated into protein. Four long ncRNAs (RNA5.0, RNA4.9, RNA1.2 and RNA2.7) account for the majority of HCMV transcription during lytic replication. Here, we review the expression and function of these long ncRNAs in the context of virus replication and pathogenesis. Long ncRNAs may contribute to HCMV evasion of the host response and manipulate cellular and viral programs to successfully persist throughout the lifetime of its host.

Codon usage bias in human cytomegalovirus and its biological implication

Human cytomegalovirus (HCMV) infection, a worldwide contagion, causes a serious disorder in infected individuals. Analysis of codon usage can reveal much molecular information about this virus. The effective number of codon (ENC) values, relative synonymous codon usage (RSCU) values, codon adaptation index (CAI), and nucleotide contents was investigated in approximately 160 coding sequences (CDS) among 17 human cytomegalovirus genomes using the software CodonW. Linear regression analysis and logistic regression were performed to explore the preliminary data. The results showed that, overall, HCMV genomes had low codon usage bias (mean ENC=47.619). However, the ENC of individual CDS varied widely and was distributed unevenly between host-related genes and viral-self-function genes (P=0.002, odds ratio (OR)=3.194), as did the GC content (P=0.016, OR=2.178). The ENC values correlated with CAI, GC content, and the nucleotide composing at the 3rd codon position (GC3s) (P<0.001). There was a significant variation in the codon preference that depended on the RSCU data. The predicted ENC curve suggested that mutational pressure, rather than natural selection, was one of the main factors that determined the codon usage bias in HCMV. Among 123 genes with known function, the genes related to viral self-replication and viral-host interaction showed different ENC and CAI values, and GC and GC3s contents. In conclusion, the detailed codon usage bias theoretically revealed information concerning HCMV evolution and could be a valuable additional parameter for HCMV gene function research.