Intraocular human cytomegaloviruses of ocular diseases are distinct from those of viremia and are capable of escaping from innate and adaptive immunity by exploiting HLA-E-mediated peripheral and central tolerance.

Human cytomegalovirus (HCMV) infections develop into CMV diseases that result in various forms of manifestations in local organs. CMV-retinitis is a form of CMV disease that develops in immunocompromised hosts with CMV-viremia after viruses in the peripheral circulation have entered the eye. In the HCMV genome, extensive diversification of the UL40 gene has produced peptide sequences that modulate NK cell effector functions when loaded onto HLA-E and are subsequently recognized by the NKG2A and NKG2C receptors. Notably, some HCMV strains carry UL40 genes that encode peptide sequences identical to the signal peptide sequences of specific HLA-A and HLA-C allotypes, which enables these CMV strains to escape HLA-E-restricted CD8+T cell responses. Variations in UL40 sequences have been studied mainly in the peripheral blood of CMV-viremia cases. In this study, we sought to investigate how ocular CMV disease develops from CMV infections. CMV gene sequences were compared between the intraocular fluids and peripheral blood of 77 clinical cases. UL40 signal peptide sequences were more diverse, and multiple sequences were typically present in CMV-viremia blood compared to intraocular fluid. Significantly stronger NK cell suppression was induced by UL40-derived peptides from intraocular HCMV compared to those identified only in peripheral blood. HCMV present in intraocular fluids were limited to those carrying a UL40 peptide sequence corresponding to the leader peptide sequence of the host's HLA class I, while UL40-derived peptides from HCMV found only in the peripheral blood were disparate from any HLA class I allotype. Overall, our analyses of CMV-retinitis inferred that specific HCMV strains with UL40 signal sequences matching the host's HLA signal peptide sequences were those that crossed the blood-ocular barrier to enter the intraocular space. UL40 peptide repertoires were the same in the intraocular fluids of all ocular CMV diseases, regardless of host immune status, implying that virus type is likely to be a common determinant in ocular CMV disease development. We thus propose a mechanism for ocular CMV disease development, in which particular HCMV types in the blood exploit peripheral and central HLA-E-mediated tolerance mechanisms and, thus, escape the antivirus responses of both innate and adaptive immunity.

Corrigendum: Intraocular human cytomegaloviruses of ocular diseases are distinct from those of viremia and are capable of escaping from innate and adaptive immunity by exploiting HLA-E-mediated peripheral and central tolerance.

[This corrects the article DOI: 10.3389/fimmu.2022.1008220.].

Effective diagnosis by real-time PCR of herpes simplex diffuse endotheliitis that is similar in appearance to fungal keratitis: case series.

PURPOSE: Herpes simplex diffuse endotheliitis with accompanying feathery infiltration is difficult to diagnose due to corneal findings that are similar to fungal keratitis. This case series reports on the effectiveness of using real-time polymerase chain reaction (PCR) to diagnose herpes simplex diffuse endotheliitis that is similar in appearance to fungal keratitis. METHODS: After extracting corneal smear sample DNA, samples were then applied to two independent PCR assays, a qualitative multiplex 24-pathogen strip PCR assay, and a quantitative real-time PCR assay of herpes simplex virus type 1 (HSV-1). RESULTS: All 3 cases showed ciliary injection, feathery infiltration in the corneal stroma and hypopyon, which are corneal findings similar to that observed for fungal keratitis. Retrocorneal plaques, which showed clear boundaries between the corneal endothelial surfaces and retrocorneal plaques in anterior segment optical coherence tomography, were observed in 2 out of 3 cases. Corneal scraping was performed in all cases, followed by initiation of antifungal treatment. However, real-time PCR of the corneal scraping detected 6.0 × 106, 1.0 × 105 and 5.0 × 105 copies/µg glyceraldehyde 3-phosphate dehydrogenase (GAPDH) of HSV-1 DNA per each microgram of the samples. Fungi were not cultured in any of the cases. After switching the medication from antifungal to antiviral, the feathery corneal infiltration was cured with only mild scarring. CONCLUSIONS: Real-time PCR was an effective tool in diagnosing HSV diffuse endotheliitis with feathery infiltration. Topical corticosteroids in conjunction with oral and topical antivirals were an effective treatment.

Bilateral Necrotizing Herpes Simplex Keratitis in an Immunocompetent Patient With Genetic Analysis of Herpes Simplex Virus 1.

PURPOSE: To report a case of severe bilateral necrotizing herpes simplex keratitis (HSK) in an immunocompetent patient, with genotyping of the underlying herpes simplex virus 1 (HSV-1). METHODS: Genetic analyses of HSV-1 in tear samples were performed with polymerase chain reaction-based restriction fragment length polymorphism, targeting the viral genes unique short (US)2, US4 (glycoprotein G), and US7 (glycoprotein I). RESULTS: A 64-year-old woman with no history of atopy or immune disorders manifested bilateral keratitis with geographic ulcer. Her initial visual acuity was 20/1000 (OD) and 20/20 (OS). Polymerase chain reaction testing of a tear sample revealed the presence of HSV-1 in both eyes, and the patient was diagnosed with bilateral HSK. Both eyes progressed to necrotizing keratitis during the treatment course. Continuous intensive treatment, at first with acyclovir ointment and oral valacyclovir and later with steroid eye drops for stromal keratitis, finally improved the patient's condition. However, after 2 years, her visual acuity was limited to 20/250 (OD) and 20/60 (OS) because of corneal opacity from scarring. We found that the strain in the current case had a genotype combination of C/A/B (for US2/US4/US7), a known pattern in Japan, in both eyes. CONCLUSIONS: We successfully performed an unprecedented genetic analysis of an HSV-1 strain isolated from a case of bilateral necrotizing HSK in an immunocompetent patient. The association of the HSV-1 genotype with the clinical manifestation remains unclear, calling for more data from new cases, especially from different geographic regions.

Infection of endotheliotropic human cytomegalovirus of trabecular meshwork cells.

PURPOSE: Human cytomegalovirus (HCMV) infections can cause endotheliitis which is associated with an elevation in the intraocular pressure (IOP). However, the mechanism of the IOP elevation has not been established. The purpose of this study was to determine whether HCMV strains which are capable of infecting corneal endothelial cells can also replicate and induce anti-viral responses, and can reorganize the actin cytoskeleton in trabecular meshwork cells. STUDY DESIGN: Experimental study design. METHODS: Cultured primary human trabecular meshwork cells (HTMCs) were infected with the Towne or TB40/E strains of HCMV. TB40/E is trophic for vascular endothelial and corneal endothelial cells. Real-time PCR, western blot, and fluorescent immunostaining have been used to determine whether HCMV-infected HTMCs will support the expression of viral mRNA and protein, allow viral replication, and elicit anti-viral host responses. We also determined whether lytic replication was present after HCMV infection. RESULTS: HCMV infection led to the expression of viral mRNA and proteins of IE1, glycoprotein B(gB), and pp65. TB40/E infection induced interferon-ß, a sign of host anti-viral immune response and monocyte chemotactic protein-1 (MCP-1) as IOP-related chemokine. Together with the induction of the regulators of actin cytoskeleton, myosin phosphatase Rho interacting protein (MPRIP) and MCP-1, TB40/E induced a high level of expression of viral proteins, including IE1, gB, and pp65 as well as actin stress fiber formation, and achieved pathogenically high viral titers. CONCLUSIONS: Human trabecular meshwork cells support the replication of endotheliotropic TB40/E strain of HCMV which indicates that this strain may have high virulence for trabecular meshwork.

Genetic analysis of varicella-zoster virus in the aqueous humor in uveitis with severe hyphema.

BACKGROUND: Genetic variations have been identified in the genome of varicella-zoster virus (VZV) strains using vesicle fluid, varicella scabs and throat swab samples. We report a rare case of VZV-associated uveitis with severe hyphema, which was immediately diagnosed by polymerase chain reaction (PCR) using the aqueous humor, in which we were able to analyze the VZV genotype for the first time. CASE PRESENTATION: A 16-year-old Japanese boy was referred to our hospital with a 20-day history of unilateral anterior uveitis and 11-day history of hyphema. At presentation, details of the iris, the iridocorneal angle, and the fundus were not visible due to the severe hyphema. Serum anti-VZV IgG and anti-VZV IgM were elevated, and 1.61 × 109 copies/mL of VZV-DNA were detected by real-time PCR using the aqueous humor. As there were no eruptions on his face or body, we diagnosed zoster sine herpete and started intravenous administration of prednisolone and acyclovir. The hyphema completely disappeared 2 weeks after presentation, while sectorial iris atrophy and mild periphlebitis of the fundus became gradually apparent. Anterior inflammation and periphlebitis gradually improved and VZV-DNA in the aqueous humor was reduced to 1.02 × 106 copies/mL at 4 weeks after presentation. Examination by slit lamp microscope revealed no inflammation after 5 months, and VZV-DNA could no longer be detected in the aqueous humor. Serum anti-VZV IgG and anti-VZV IgM also showed a gradual decrease along with improvement in ocular inflammation. The genetic analysis of multiple open reading frames and the R5 variable repeat region in the VZV genes, using DNA extracted from the aqueous humor at presentation, showed that the isolate was a wild-type clade 2 VZV strain (prevalent in Japan and surrounding countries) with R5A allele and one SNP unique to clade 1 (both are major types in Europe and North America). CONCLUSIONS: VZV-associated uveitis may develop hyphema that obscures ocular inflammation, thus PCR analysis using the aqueous humor is the key investigation necessary for the diagnosis. The measurement of VZV-DNA copies by real-time PCR would be useful for evaluation of therapeutic effects. We could amplify and analyze VZV genotype using the aqueous humor including a very large number of VZV-DNA copies (1.61 × 109 copies/mL).

Corneal endothelial cells activate innate and acquired arm of anti-viral responses after cytomegalovirus infection.

Infection of the corneal endothelial cells by human cytomegalovirus (CMV) is an important cause of corneal endotheliitis. CMV endotheliitis is difficult to completely cure and relapses are frequent. This can cause blinding corneal bullous keratopathy. However, the pathogenesis of CMV endotheliitis remains undetermined. To understand the immunopathology of endotheliitis, we examined how corneal endothelial cells prime the anti-viral immunity after CMV infection based on global transcriptional responses. To accomplish this, human corneal endothelial (HCEn) cells were infected with CMV, and the global transcriptional responses were determined by microarray analyses for primary anti-viral responses using network analysis. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and protein array analyses were used to examine whether anti-viral cytokines were induced, i.e., to determine whether innate immune responses were activated. To examine whether priming of acquired immune response was activated, CMV-infected HCEn cells were co-cultured with allogeneic CD8+ T cells from CMV seropositive donors and tested for priming activity for the CD8+ effector T cells by measuring interferon-γ secretion. The CMV-induced responses of HCEn cells were characterized by type I interferon and pattern recognition receptor pathways which represent innate immune priming. The global transcriptional activation was specifically associated with antigen presentation with the antimicrobial response functions. Protein array analyses indicated a significant increase in the secretion of anti-viral inflammatory cytokines including CXCL10 as innate immune responses. When HCEn cells were examined to determine whether CMV infection activated anti-viral acquired immunity, CMV-infected HCEn cells directly stimulated the proliferation of CD8+ T cells from CMV-seropositive donors, and pp65 viral epitope induced interferon-γ secretion from the CD8+ T cells. We conclude that CMV-infected HCEn cells induce innate immune priming along with provisions of acquired immune priming of CD8+ effector T cells. This information should help in the development of useful diagnostic procedures and efficacious therapeutic strategy to treat refractory corneal endotheliitis.

Cytomegalovirus retinitis followed by immune recovery uveitis in an elderly patient with rheumatoid arthritis undergoing administration of methotrexate and tofacitinib combination therapy.

Cytomegalovirus (CMV) retinitis is an opportunistic ocular infection most commonly observed in patients infected with human immunodeficiency virus (HIV). We present a rare case of CMV retinitis that developed in a non-HIV patient with rheumatoid arthritis (RA). Over the preceding 5 months, a family doctor had been treating the 78-year-old male patient with a combination therapy of methotrexate (MTX) and tofacitinib (TOF). CMV retinitis occurred when the patient's CD4+ T cells were low (196 cells/µl), and preceded the onset of Pneumocystis pneumonia. MTX and TOF were stopped after the diagnosis of CMV retinitis. While intravenous and intravitreal ganciclovir administration significantly improved the CMV retinitis, uveitis developed 3 months later during the maintenance therapy with oral valganciclovir, concomitantly with the recovery of the CD4+ T cell counts. As we believed this uveitis was caused by the immune reconstitution mechanism, we treated the patient with a retrobulbar injection of corticosteroids. During the 6 months following the cessation of MTX and TOF, there was no flare-up of the RA. Cases of CMV retinitis and immune recovery uveitis in RA patients have been rarely reported in the literature. In the current case, the intensive immunosuppressive therapy in this elderly patient might have been the cause of this unusual opportunistic complication of RA.

Analysis of human cytomegalovirus replication in primary cultured human corneal endothelial cells.

BACKGROUND/AIMS: Since the first case of human cytomegalovirus (HCMV)-induced corneal endotheliitis in which HCMV DNA was detected from the patient's aqueous humour using PCR, the clinical evidence for HCMV endotheliitis has been accumulating. However, it remains to be confirmed whether HCMV can efficiently replicate in corneal endothelial cells. We, therefore, sought to determine whether primary cultured human corneal endothelial cells (HCECs) could support HCMV replication. METHODS: Human foreskin fibroblasts (HFFs) have been shown to be fully permissive for HCMV replication, and are commonly used as an in vitro model for HCMV lytic replication. Therefore, primary cultured HCECs or HFFs were infected with the vascular endotheliotropic HCMV strain TB40/E or laboratory strain Towne. We then compared viral mRNA and protein expression, genome replication and growth between the TB40/E-infected and Towne-infected HCECs and HFFs. RESULTS: When HCECs were infected with TB40/E or Towne, rounded cells resembling owl's eyes as well as viral antigens were detected. Viral mRNA synthesis and protein expression proceeded efficiently in the HCECs and HFFs infected with TB40/E or Towne at a high multiplicity of infection (MOI). Similarly, the viral genome was also effectively replicated, with UL44--a viral DNA polymerase processivity factor--foci observed in the nuclei of HCECs. HCECs produced a substantial number of infectious virions after infection with TB40/E at both a high and low MOI. CONCLUSIONS: Primary cultured HCECs could efficiently support HCMV replication after infection at both a high and low MOI.