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

Pharmacokinetics of ganciclovir eye drops: a comparative study of solutions prepared from ganciclovir for intravenous infusion and ganciclovir gel

PURPOSE

To evaluate the pharmacokinetics of ganciclovir eye drops by comparing solutions prepared from ganciclovir for intravenous infusion and ganciclovir gel and to assess the impact of systemic administration on drug levels in ocular tissues and serum.

STUDY DESIGN

Experimental study design.

METHODS

Ganciclovir solutions (0.5% and 1.0%) prepared by diluting DENOSINE ® IV Infusion in saline and 0.15% ganciclovir gel (Virgan®) were topically administered in rabbit eyes, with and without concomitant systemic administration of ganciclovir. The concentrations of ganciclovir in the corneal epithelium, stroma, and endothelium, aqueous humor; and blood plasma were analyzed by high-performance liquid chromatography (HPLC).

RESULTS

The ganciclovir solutions (0.5% and 1.0%) maintained therapeutic ganciclovir levels in the corneal endothelium above the effective dose required for 50% inhibition (ED50) up to 6 h, albeit with a swift decline thereafter. The 0.15% ganciclovir gel maintained higher therapeutic concentrations in the corneal endothelium for up to 12 h, exceeding the ED50. Serum concentrations of ganciclovir were significantly elevated in the groups receiving combined systemic administration.

CONCLUSION

Topical application of 0.15% ganciclovir gel maintained high endothelial concentrations, well above the therapeutic threshold, with or without systemic administration. Furthermore, the observed increase in ganciclovir levels within the plasma and aqueous humor following systemic administration posits it as a viable strategy for severe cases of cytomegalovirus corneal endotheliitis or those inadequately managed by local treatments alone.

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.

Cytomegalovirus Corneal Endotheliitis: A Comprehensive Review

Cytomegalovirus (CMV) anterior uveitis and corneal endotheliitis are the most common ocular diseases caused by CMV infections in immunocompetent patients. The incidence of CMV corneal endotheliitis is relatively high in middle-aged men. CMV corneal endotheliitis presents with mild anterior chamber inflammation, corneal edema, keratic precipitates, and elevated intraocular pressure. It resembles Posner-Schlossman syndrome and Fuchs uveitis because of the elevated intraocular pressure. Without proper diagnosis and treatment, it may progress to bullous keratopathy or glaucoma, necessitating keratoplasty or glaucoma surgery. Therefore, early diagnosis and treatment are important for a good prognosis. Aqueous humor analysis can facilitate the diagnosis of CMV corneal endotheliitis, and early antiviral treatment can decrease the risk of corneal compensation or glaucomatous optic atrophy. In this article, we review the epidemiology, pathogenesis, clinical manifestations, diagnosis, treatment, and prognosis of CMV corneal endotheliitis along with the evidence for early clinical diagnosis and active antiviral treatment.

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.

Establishing an Animal Model of Cytomegalovirus Keratouveitis in Rats: Broad Infection of Anterior Segment Tissue by Cytomegalovirus

Purpose

Considering the difficulty of obtaining adequate biological tissue in clinical practice, we established an animal model of cytomegalovirus (CMV) keratouveitis in rats and investigated the viral infection sites and corresponding imaging and histopathological features.

Methods

Subconjunctival injection and topical use of dexamethasone were used to induce ocular immunosuppression in rats followed by intracameral inoculation of murine cytomegalovirus (MCMV). The clinical manifestations, intraocular pressure (IOP) and imaging changes were observed. Infected eyes were further examined by immunofluorescence, light microscopy, and electron microscopy. MCMV RNA was detected by reverse transcription-polymerase chain reaction.

Results

Typical keratouveitis occurred in the experimental rats and was characterized by corneal edema, keratic precipitates, and iridocyclitis with increased IOP. Corneal endothelial lesions displayed as “black holes,” enlarged intercellular gaps, and high-intensity cellular infiltration by confocal microscopy, consistent with the pathological changes of “ballooning degeneration,” endothelial cell detachment, and inflammatory cell infiltration. Mitochondrial edema was the most prominent organelle lesion in endothelial cells. Trabeculitis, mechanical obstruction of Schlemm's canal, and anterior chamber angle stenosis accounted for elevated IOP. Inflammation of the iris and ciliary body tended to transform into a chronic form. Immunofluorescence revealed that corneal endothelial cells, iris cells, trabecular meshwork cells, and monocytes could be infected by MCMV. MCMV RNA was found in the anterior segments after infection.

Conclusions

CMV can widely infect anterior segment tissue, including the corneal endothelium, iris, and trabecular meshwork, in vivo, inducing the corresponding clinical manifestations. Corneal endotheliitis and hypertensive anterior uveitis could be the specific stage of anterior segment infection of CMV.

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.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Diagnostic efficacy of real-time PCR for ocular cytomegalovirus infections

PURPOSE

The aim of this study is to determine the efficacy of quantitative real-time PCR (qPCR) and clinical characteristics to diagnose ocular cytomegalovirus (CMV) infections.

METHODS

The technical factors were assessed by the outcomes of the qPCR assay at five institutions in Japan using the WHO International Standard of cytomegalovirus. The clinical factors were assessed by examining the aqueous humor samples of 197 eyes of 197 consecutive patients suspected of CMV using the receiver operating characteristics (ROCs).

RESULTS

All of the institutions had excellent detection efficacy, although the copy number ranged from 0.82 to 4.66 copies/IU. In the clinical samples, CMV was detected in 51 eyes, and the amount of CMV DNA was significantly higher for CMV retinitis. In corneal diseases, the amount of CMV DNA was significantly associated with frequency of recurrences and IOP elevations. The sensitivity and specificity of qPCR for the diagnosis was 90.0 and 98.7%, respectively. For the corneal and anterior uveitis types of CMV diseases, the area under the curve (AUC) of qPCR was 0.95 and 0.96, followed by frequency of recurrences with AUC of 0.89 and 0.82, and IOP elevations with AUC of 0.78 and 0.76. Unclassified cytomegalovirus detection, which did not meet diagnostic criteria of CMV corneal endotheliitis, anterior uveitis, or retinitis, was 4.6%, and it was significantly associated with corneal diseases and history of corneal transplantation.

CONCLUSIONS

qPCR with standardization is specific and accurate; however, the inclusion and knowledge of the clinical characteristics improve the diagnostic efficacy.

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.

Polymorphisms and features of cytomegalovirus UL144 and UL146 in congenitally infected neonates with hepatic involvement

Human cytomegalovirus is a significant agent of hepatic involvement in neonates. In this study, we investigated the polymorphisms and features of the viral genes UL144 and UL146 as well as their significance to congenital hepatic involvement. In 79 neonates with congenital cytomegalovirus infection and hepatic involvement, full length UL144 and UL146 were successfully amplified in 73.42% and 60.76% of cases, respectively. Sequencing indicated that both genes were hypervariable. Notably, UL144 genotype B was highly associated with aspartate aminotransferase (P = 0.028) and lactate dehydrogenase (P = 0.046). Similarly, UL146 genotype G1 and G13 were significantly associated with CMV IgM (P = 0.026), CMV IgG (P = 0.034), alanine aminotransferase (P = 0.019), and aspartate aminotransferase (P = 0.032). In conclusion, dominant UL144 (genotype B) and UL146 (genotype G1 and G13) genotypes are associated with elevated levels of enzymes and CMV IgM and IgG of cytomegalovirus infection.

Posner-Schlossman syndrome

Posner-Schlossman syndrome, or glaucomatocyclitic crisis, is a unilateral ocular condition characterized by recurrent attacks of nongranulomatous anterior uveitis and raised intraocular pressure that can result in chronic secondary glaucoma. This relatively rare disease is most likely the result of recurrent cytomegalovirus infection and affects predominantly middle-aged males. Diagnosis is largely clinical, with aqueous and blood sampling aiding the identification of any underlying infectious cause. Successful disease management is often achieved by topical treatment, although systemic therapy and even surgical intervention may be required. We discuss our current understanding of Posner-Schlossman syndrome, from its pathophysiology through to recommended treatment options.

The effect of topical application of 0.15% ganciclovir gel on cytomegalovirus corneal endotheliitis

BACKGROUND/AIMS

The aim of this study was to evaluate the therapeutic efficacy and drug transfer of topical application of 0.15% ganciclovir (GCV) gel on cytomegalovirus (CMV) corneal endotheliitis.

METHODS

This study is a multicentre, prospective, interventional case series. Seven eyes of seven immunocompetent patients diagnosed with CMV corneal endotheliitis, based on clinical manifestations and qualitative PCR, were enrolled in this study. The patients were treated with topical applications of 0.15% GCV gel six times daily for 12 weeks without concomitant systemic GCV. Clinical evaluations and quantitative PCR of CMV were performed, and GCV concentrations in aqueous humour were measured by liquid chromatography/tandem mass spectrometry.

RESULTS

Clinical improvement of coin-shaped lesions, other types of keratic precipitates, corneal oedema, and anterior chamber inflammation was confirmed at the 4-week visit in all seven eyes. The GCV treatment significantly decreased the CMV copy numbers (p<0.0001). After 12 weeks of treatment, six eyes recovered clear corneas with good vision, and endothelial function was well maintained. Detectable levels of GCV were confirmed in the aqueous humour of all the eyes. The mean GCV concentration in the anterior chamber was 162.0±202.4 ng/mL. The re-emergence of CMV without symptoms was observed in one eye with lower drug transfer. No side effects were observed.

CONCLUSIONS

Clinical improvement and reduced CMV copy numbers in the aqueous humour were confirmed in the CMV corneal endotheliitis cases. Although the case numbers are limited and long-term follow-up is necessary, the topical application of 0.15% GCV gel appears to be a useful treatment option for CMV endotheliitis.

TRIAL REGISTRATION NUMBER

UMIN000012435.