Idiopathic no more: clues to the pathogenesis of Fuchs heterochromic iridocyclitis and glaucomatocyclitic crisis

Comparison of Clinical Characteristics between Rubella Virus and Cytomegalovirus Associated Chronic Unilateral Anterior Uveitis

PURPOSE

To identify the clinical characteristics that may predict the diagnosis of Rubella virus (RV) or Cytomegalovirus (CMV) among cases of chronic treatment resistant or steroid dependent unilateral anterior uveitis (AU).

METHODS

Thirty-three consecutive patients with a diagnosis of CMV and 32 patients with RV chronic AU were enrolled. The respective frequency of certain demographic and clinical characteristics was compared between the two groups.

RESULTS

The presence of abnormal vessels in the anterior chamber angle (75% and 6.1%, respectively, p < .001), vitritis (68.8%-12.1%, p < .001), iris heterochromia (40.6%-15.2%, p = .022) and iris nodules (21.9%-3%, p = .027) were more common among RV AU. Conversely, intraocular pressure greater than 26 mmHg was more commonly encountered in CMV associated AU (63.6%-15.6%, respectively, p < .001) and large keratic precipitates were detected only in CMV-associated AU.

CONCLUSIONS

RV- and CMV-induced chronic AU differ significantly in the prevalence of specific clinical characteristics.

Cytokine Changes in the Aqueous Humor in Rubella-Related Fuchs Heterochromic Iridocyclitis

This retrospective study is aimed at determining the correlation between cytokine levels and virus status in the aqueous humor of 38 patients with Fuchs heterochromic iridocyclitis (FHI) with/without a viral presence between May 2017 and January 2020. The levels of cytokines were analyzed in the groups with and without virus-related FHI. Among the patients, 50% had rubella virus, 5.26% had cytomegalovirus, and 2.63% had herpes simplex virus infections. The expression of interleukin-6 (IL-6) and IL-8 was significantly higher, and that of basic fibroblast growth factor (bFGF) was significantly lower in the virus-positive group than in the virus-negative group (P = 0.015, P = 0.001, and P = 0.001, respectively). Although there was no significant difference in the mean expression of vascular cell adhesion protein 1 (VCAM-1), IL-10, and vascular endothelial growth factor (VEGF), that of VCAM-1 and IL-10 was higher (M = 1338 and M = 1390, respectively; M = 6.225 and 10.600, respectively) and that of VEGF was lower (M = 134.5 and M = 38.70, respectively) in the virus-positive group than in the virus-negative group. Similar findings were observed for the expressions of IL-6, IL-8, and bFGF in the rubella-positive and rubella-negative groups. Viral presence was highly related to FHI, especially that of the rubella virus. High levels of inflammatory cytokines and low levels of neovascularization-related factors are involved in rubella-related FHI. These study findings could be helpful in the diagnosis and treatment of FHI.

Rational laboratory testing in uveitis: A Bayesian analysis

Uveitis encompasses a heterogeneous group of clinical entities with the common feature of intraocular inflammation. In addition to patient history and examination, a focused set of laboratory investigations is frequently necessary to establish a specific diagnosis. There is limited consensus among uveitis specialists regarding appropriate laboratory evaluation for many distinct patient presentations. The appropriateness of a laboratory test for a given case of uveitis will depend on patient-specific as well as epidemiologic factors. Bayesian analysis is a widely used framework for the interpretation of laboratory testing, but is seldom adhered to in clinical practice. Bayes theorem states that the predictive value of a particular laboratory test depends on the sensitivity and specificity of that test, as well as the prevalence of disease in the population being tested. In this review we will summarize the performance of commonly-utilized laboratory tests for uveitis, as well as the prevalence of uveitic diagnoses in different geographic practice settings. We will propose a logical framework for effective laboratory testing in uveitic disease through rigorous application of Bayesian analysis. Finally, we will demonstrate that while many highly sensitive laboratory tests offer an effective means to rule out associated systemic disease, limited test specificity and low pretest probability often preclude the diagnosis of systemic disease association with any high degree of certainty, even in the face of positive testing.

Metabolomic Profile of Posner-Schlossman Syndrome: A Gas Chromatography Time-of-Flight Mass Spectrometry-Based Approach Using Aqueous Humor

The Posner-Schlossman syndrome (PSS) is a disease with clinically recurrent unilateral anterior uveitis with markedly elevated intraocular pressure (IOP) and subsequent progression to optic neuropathy. Retrospective studies have reported increased annual incidence of PSS, especially in China. While currently, the clinical management of PSS is still challenging. Metabolomics is considered to be a sensitive approach for the development of novel targeted therapeutics because of its direct elucidation of pathophysiological mechanisms. Therefore, we adopted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) technology-based non-targeted metabolomics approach to measure comprehensive metabolic profiles of aqueous humor (AH) samples obtained from patients with PSS, with an aim to demonstrate the underlying pathophysiology, identify potential biomarkers specific to PSS, and develop effective treatment strategies. A comparative analysis was used to indicate the distinct metabolites of PSS. Pathway analysis was conducted using MetaboAnalyst 4.0 to explore the metabolic reprogramming pathways involved in PSS. Logistic regression and receiver-operating characteristic (ROC) analyses were employed to evaluate the diagnostic capability of selected metabolites. Comparative analysis revealed a clear separation between PSS and control groups. Fourteen novel differentiating metabolites from AH samples obtained from patients with PSS were highlighted. Pathway analysis identified 11 carbohydrate, amino acid metabolism and energy metabolism pathways as the major disturbed pathways associated with PSS. The abnormal lysine degradation metabolism, valine-leucine-isoleucine biosynthesis, and citrate circle were considered to weigh the most in the development of PSS. The ROC analysis implied that the combination of glycine and homogentisic acid could serve as potential biomarkers for the discrimination of control and PSS groups. In conclusion, these results revealed for the first time the identity of important metabolites and pathways contributing to the development/progression of PSS, enabled the better understanding of the mechanism of PSS, and might lead to the development of metabolic biomarkers and novel therapeutic strategies to restrict the development/progression of PSS.

Virus-Induced Anterior Uveitis (VIAU) in Immunocompromised Patients

PURPOSE

To describe the clinical characteristics, diagnosis, and treatment of VIAU in immunocompromised patients.

METHODS

A critical review of literature was performed.

RESULTS

Diagnosis and treatment of VIAU in immunocompromised patients may be a challenge due to atypical clinical-courses, severe presentations, and more frequent recurrences. A conclusive diagnosis can be made by aqueous-humour PCR-analysis. Visual prognosis depends on early diagnosis and prompt treatment. Frequent ocular examinations are recommended in HIV patients with CD-4-counts below 100 in order to rule out opportunistic ocular coinfections. It is essential to bear in mind the potential side-effects of therapeutic interventions and consider the possibility of Immune Recovery Uveitis (IRU) in eyes with treated viral retinitis after the initiation of HAART.

CONCLUSIONS

Early diagnosis and treatment of VIAU in immunocompromised patients can be achieved with high suspicion, recognizing clinical features, and obtaining specimens for molecular diagnostic testing in order to avoid usually severe ocular morbidity.

Intra-cameral level of ganciclovir gel, 0.15% following topical application for cytomegalovirus anterior segment infection: A pilot study

Purpose

To investigate the intra-cameral level of ganciclovir following topical application of ganciclovir gel, 0.15% for cytomegalovirus (CMV) anterior segment infection.

Design

Non-randomized, prospective, interventional clinical study.

Methods

Patients with active CMV anterior segment infection seen at Singapore National Eye Centre, confirmed by positive CMV real time PCR (RT-PCR) of the aqueous humor, that had not been treated with any form of ganciclovir in the preceding 1 month were recruited. They were treated with ganciclovir gel, 0.15% 1cc 5 times a day. Following 6 weeks of treatment, CMV load in the aqueous humor was measured using CMV RT-PCR and the ganciclovir drug levels in tears and aqueous humor were measured using high-performance liquid chromatography-mass spectrometry. The clinical features of the disease activity and the central corneal thickness (CCT) were recorded at the baseline and post-treatment.

Results

There were 29 eyes of 29 patients, of which 23 eyes had CMV anterior uveitis and 6 eyes had CMV endotheliitis. At the end of week 6, 26 eyes had undetectable CMV titre in the aqueous humor and no anterior chamber (AC) activity. Two patients had an increased CMV titre and increased AC inflammation. Both of these patients were non-compliant with the treatment. One patient had a reduced CMV titre in the aqueous humor with minimal AC inflammation. The mean ganciclovir concentration in the aqueous humor and the tears were 17.4 ± 30.6 ng/ml and 20,420.9 ± 33,120.8 ng/ml respectively. Mean CCT was 552.2 ± 42.3 microns. There was a weak correlation between the ganciclovir concentration in the aqueous humor and CCT (Spearmen's r = + 0.42, p = 0.025). There was no significant correlation between the ganiclovir concentration in the tears and CCT (Spearmen's r = + 0.39, p = 0.11).

Conclusion

Ganciclovir levels in the aqueous humor was below the 50% inhibitory dose (ID50) for CMV replication, following topical application of the ganciclovir gel, 0.15%.

Trial registration

SingHealth Centralized Institutional Review Board, Singapore; R733/17/2010, ClinicalTrials.gov; NCT01647529.

Clinical Features of CMV-Associated Anterior Uveitis

Cytomegalovirus (CMV) anterior uveitis is the most common ocular manifestation of CMV disease in immunocompetent individuals. It is thought to be due to a local reactivation of latent CMV and is usually unilateral. The acute form presents as Posner-Schlossman Syndrome, a recurrent hypertensive anterior uveitis with few granulomatous keratic precipitates. There are geographic differences in the chronic form of CMV anterior uveitis. Asian patients commonly present as Fuchs Uveitis Syndrome with diffuse stellate keratic precipitates, while the European patients present with a chronic hypertensive anterior uveitis with fewer keratic precipitates that are brown in color and located inferiorly. Characteristic features of CMV anterior uveitis include mild anterior chamber inflammation, elevated intraocular pressure, stromal iris atrophy. Synechiae, macular edema and retinitis are typically absent. CMV disease may also be associated with the development of corneal endotheliitis with a reduced endothelial cell count. Long-term complications include glaucomatous optic neuropathy and cataract formation.

Enhanced cytomegalovirus infection in human trabecular meshwork cells and its implication in glaucoma pathogenesis

Cytomegalovirus (CMV) is one of the infectious causes of hypertensive anterior uveitis, which is characterized by recurrent episodes of elevated intraocular pressure (IOP) and mild anterior uveitis. Despite the potentially vision-threatening complications of this disease, the underlying mechanisms remain largely undefined. We aimed to investigate whether human trabecular meshwork (TM) cells, the key cell type that regulates IOP, could support CMV replication, as well as demonstrate the relevant pathological changes in TM. When human TM cells were infected with CMV AD169, immediate early antigens were detected 1 day post-infection (dpi); cytopathic changes including rounding, a ballooned appearance with disorganization, and a decreased number of stress fibers were noted in TM cells. The marked increase in viral DNA accumulation was observed most notably at 5 and 7 dpi, suggesting that the active viral infection in human TM cells could be the key mechanism underlying the elevation of IOP in anterior viral uveitis. Notably, CMV infection enhanced the production of transforming growth factor (TGF)-β1, an upstream molecule that increases the resistance of the outflow pathway in human TM cells. The increase of TGF-β1 was countervailed by additional treatment with corticosteroids. Our results provide a pathogenic mechanism for IOP elevation in viral anterior uveitis.

Evaluation of Retinal and Choroidal Thickness in Fuchs' Uveitis Syndrome

Purpose. We aimed to investigate retinal and choroidal thickness in the eyes of patients with Fuchs' uveitis syndrome (FUS). Methods. Fifteen patients with unilateral FUS and 20 healthy control subjects were enrolled. Spectral domain optical coherence tomography (Spectralis HRA+OCT, 870 nm; Heidelberg Engineering, Heidelberg, Germany) was used to obtain retinal and choroidal thickness measurements. The retinal nerve fiber layer (RNFL) thickness, macular thickness, and choroidal thickness of the eyes with FUS were compared with the unaffected eye and the eyes of healthy control subjects. Results. The mean choroidal thickness at fovea and at each point within the horizontal nasal and temporal quadrants at 500 μm intervals to a distance of 1500 µm from the foveal center was significantly thinner in the affected eye of FUS patients compared with the unaffected eye of FUS patients or the eyes of healthy control subjects. However, there were no significant differences in RNFL or macular thickness between groups. Conclusions. Affected eyes in patients with FUS tend to have thinner choroids as compared to eyes of unaffected fellow eyes and healthy individuals, which might be a result of the chronic inflammation associated with the disease.

Uveitis and glaucoma: new insights in the pathogenesis and treatment

Glaucoma is a potentially blinding complication of uveitis, where intraocular inflammation, secondary corticosteroid response, and varying types and degrees of angle abnormalities contribute to its pathogenesis. Management of uveitic glaucoma remains challenging. Treatment is targeted at reducing the inflammation and lowering the intraocular pressure. Recent studies have highlighted the role of viruses, such as cytomegalovirus, herpes simplex virus, and more recently Ebola virus, in the pathogenesis of uveitic glaucoma. Antiviral therapy may be beneficial in eyes with detectable viral DNA. The success of glaucoma surgery is decreased in eyes with uveitic glaucoma, and surgical interventions are associated with a higher incidence of postoperative complications. Novel glaucoma surgical and laser treatments may improve the predictability of surgery for uveitic glaucoma, but these require further evaluation.

Genomic characterization of a persistent rubella virus from a case of Fuch' uveitis syndrome in a 73 year old man

BACKGROUND

Many cases of Fuchs' uveitis have been associated with persistent rubella virus infection. A 73-year-old male patient with typical Fuchs' Uveitis Syndrome (FUS) first experienced heterochromia of the left eye at the age fourteen, when rubella was endemic in the US.

OBJECTIVES

The purposes of this report are to describe the patient's FUS clinical presentations and to characterize the virus detected in the vitreous fluid.

STUDY DESIGN

The patient underwent a therapeutic pars plana vitrectomy in May 2013. A real-time RT-PCR assay for rubella virus was performed on the vitreous fluid by Focus Diagnostics. Additional real-time RT-PCR assays for rubella virus detection and RT-PCR assays for generation of templates for sequencing were performed at the Centers for Disease Control and Prevention (CDC).

RESULTS

The results from Focus Diagnostics were positive for rubella virus RNA. Real-time RT-PCR assays at CDC were also positive for rubella virus. A rubella virus sequence of 739 nucleotides was determined and phylogenetic analysis showed that the virus was the sole member of a new phylogenetic group when compared to reference virus sequences.

CONCLUSIONS

While FUS remains a clinical diagnosis, findings in this case support the association between rubella virus and the disease. Phylogenetic analysis provided evidence that this rubella virus was likely a previously undetected genotype which is no longer circulating. Since the patient had rubella prior to 1955, this sequence is from the earliest rubella virus yet characterized.

Intermediate uveitis: an unusual presentation of cytomegalovirus intraocular infection in an immunocompetent patient

We report a case of cytomegalovirus (CMV) intraocular infection in an otherwise healthy 51-year-old patient, presenting atypically as isolated intermediate uveitis without retinitis or retinal vasculitis. The patient had a confirmed CMV infection as a cause of her intraocular inflammation via PCR DNA testing of an aqueous sample. Appropriate oral antiviral therapy was initiated, and resulted in complete resolution of inflammation and improvement in visual acuity. Prophylactic therapy was instituted thereafter.

Detection of the progression of retinal nerve fiber layer loss by optical coherence tomography in a patient with glaucomatocyclitic crisis

A 30-year-old man presented with glaucomatocyclitic crisis, also known as Posner–Schlossman syndrome, and acute intraocular pressure elevation. Changes in the longitudinal retinal nerve fiber layer (RNFL) and the cup-to-disc (C/D) ratio of the optic disc were detected by Stratus optical coherence tomography (OCT). The average RNFL thickness in the affected eye was greater than that in the unaffected eye on Day 3 (132.99 μm, C/D ratio: 0.24 vs. 105 μm, C/D ratio: 0.26). However, the RNFL thickness continued to decrease and the C/D ratio progressively increased in the affected eye over 12 months (60 μm, C/D ratio: 0.67), although the intraocular pressure was controlled at <21 mmHg during that period. Glaucomatous visual field defects were also found. A progressive decrease in the thickness of the RNFL was demonstrated by Stratus optical coherence tomography following an elevation in the acute intraocular pressure in the patient. Prompt treatment and longitudinal monitoring are necessary to prevent and detect glaucomatous damage.

Clinical outcomes in cytomegalovirus-positive Posner-Schlossman syndrome patients treated with topical ganciclovir therapy

PURPOSE

To evaluate the clinical characteristics and therapeutic outcomes of cytomegalovirus (CMV)-positive Posner-Schlossman syndrome patients undergoing topical ganciclovir treatment.

DESIGN

Retrospective, comparative, and interventional case series.

METHODS

One eye of each of 126 consecutive Posner-Schlossman syndrome patients was investigated using aqueous polymerase chain reaction (PCR) between January 2006 and June 2013. The initial presentations and follow-up data of the CMV-positive patients (68 eyes) and CMV-negative patients (58 eyes) were compared.

RESULTS

Severe endothelial cell loss (P < .001) and a higher number of eyes requiring glaucoma filtering surgery (P = .017) were observed in CMV-positive Posner-Schlossman syndrome patients. All CMV-infected eyes treated with continual topical 2% ganciclovir exhibited an undetectable CMV level at the following taps. During follow-up, the average number of antiglaucomatous agents decreased, and a similar frequency of intraocular pressure (IOP) spikes was observed in both groups (P = .358). Patients with CMV-positive eyes with a disease duration over 5 years were likely to require glaucoma surgery (P = .024, log-rank test). All patients receiving surgery exhibited CMV-negative PCR during the IOP attack, but experienced severe peripheral anterior synechiae and pigment clogging. Both groups exhibited a similar endothelial cell decrease (P = .243) and probability of progressive endothelial cell loss (P = .219, log-rank test).

CONCLUSION

Ganciclovir treatment was effective for clearing the viral load, assisting the IOP control, and preserving the corneal endothelium of CMV-positive Posner-Schlossman syndrome patients. Early diagnosis and proper treatment could decrease the risk of advanced glaucoma and avoid glaucoma surgery in long-lasting cases.

Long-term results of oral valganciclovir for treatment of anterior segment inflammation secondary to cytomegalovirus infection

Background

The purpose of this study was to assess the efficacy of oral valganciclovir in the treatment of anterior segment inflammation caused by cytomegalovirus (CMV) infection.

Methods

Consecutive patients with anterior segment inflammation due to CMV causing anterior uveitis or corneal endotheliitis treated with oral valganciclovir were reviewed. Diagnosis of CMV infection was confirmed by polymerase chain reaction of the aqueous aspirate prior to commencement of oral valganciclovir. All patients were treated with an oral loading dose of 900 mg valganciclovir twice daily for at least 2 weeks, followed by an additional 450 mg valganciclovir twice-daily maintenance therapy. Changes in visual acuity, intraocular pressure (IOP), use of antiglaucomatous eye drops, and recurrence were analyzed.

Results

Thirteen eyes of 11 patients were followed for a mean of 17.2 months. Two patients had bilateral corneal endotheliitis. All eyes had absence of anterior segment inflammation within 3 weeks after treatment. Following treatment, the mean logMAR visual acuity improved significantly from 0.58 at baseline to 0.37 at the last follow-up (P = 0.048). The mean IOP and number of antiglaucomatous eye drops also decreased significantly (P = 0.021 and P = 0.004, respectively). Five (38.5%) eyes had recurrence of anterior uveitis after valganciclovir was stopped and required retreatment with oral valganciclovir.

Conclusion

Oral valganciclovir appeared to be effective in controlling CMV anterior uveitis, resulting in visual improvement and IOP reduction following control of inflammation. However, despite the initial clinical response in all cases, recurrence after cessation of oral valganciclovir could occur.