Role of MCP-1 and IL-8 in viral anterior uveitis, and contractility and fibrogenic activity of trabecular meshwork cells

The inflammatory chemokines, monocyte chemoattractant protein (MCP)-1 and IL-8, are produced by normal trabecular meshwork cells (TM) and elevated in the aqueous humor of primary open angle glaucoma (POAG) and hypertensive anterior uveitis associated with viral infection. However, their role in TM cells and aqueous humor outflow remains unclear. Here, we explored the possible involvement of MCP-1 and IL-8 in the physiology of TM cells in the context of aqueous outflow, and the viral anterior uveitis. We found that the stimulation of human TM cells with MCP-1 and IL-8 induced significant increase in the formation of actin stress fibers and focal adhesions, myosin light chain phosphorylation, and the contraction of TM cells. MCP-1 and IL-8 also demonstrated elevation of extracellular matrix proteins, and the migration of TM cells. When TM cells were infected with HSV-1 and CMV virus, there was a significant increase in cytoskeletal contraction and Rho-GTPase activation. Viral infection of TM cells revealed significantly increased expression of MCP-1 and IL-8. Taken together, these results indicate that MCP-1 and IL-8 induce TM cell contractibility, fibrogenic activity, and plasticity, which are presumed to increase resistance to aqueous outflow in viral anterior uveitis and POAG.

Eye Complications During Dupilumab Treatment for Severe Atopic Dermatitis

Dupilumab, the first biologic approved for treatment of atopic dermatitis, has demonstrated significant clinical effect and quality of life-enhancing capacity in clinical trials. In these, dupilumab-associated conjunctivitis where reported in a minority of patients. The present case series describe 10 patients treated with dupilumab where eye complications were very common. We have described patient characteristics, including FLG mutations, atopic history and clinical effect of dupilumab. Nine of 10 developed eye-complications, most commonly conjunctivitis (in 7/10). Other adverse events were herpes simplex virus uveitis and varicella-zoster virus meningitis. Although our case series is small, we conclude that dupilumab is an effective treatment option in severe atopic dermatitis, but that the risk of adverse events from the eyes and recurrence of herpes virus infections should be kept in mind. Close collaboration with an ophthalmologist is recommended, especially among patients with severe, long-lasting atopic dermatitis and/or previous eye disease.

Herpes Simplex Virus Acute Retinal Necrosis during Pregnancy

Purpose

As pregnancy is liable to modify immune response, the authors explored the immune functions of a pregnant patient with acute retinal necrosis (ARN) to ascertain whether pregnancy may promote the onset of infection.

Methods

Polymerase chain reaction (PCR) was used for the detection of herpes simplex virus (HSV) DNA in ocular, uterus cervix, and cerebrospinal fluid samples. Peripheral blood mononuclear cells were cultured for 72 hours with mitogens and cellular proliferation was assessed using (methyl-3H) thymidine incorporation. Flow cytometry was performed for T, B, and NK cell count using CD2, CD3, CD4, CD8 (T cells), CD19, CD20 (B cells), and a combination of CD3–CD16 and CD56 monoclonal antibodies (NK cells).

Results

Unilateral ARN, with a confluent peripheral necrotizing retinitis extending throughout the entire retina, was diagnosed clinically. The herpetic infection (herpes simplex virus 1) was confirmed using PCR of aqueous humor specimen. The immunologic study performed during and after pregnancy showed that T and B lymphocytes were quantitatively normal and responses to concanavalin A, phytohemagglutinin, and pokeweed mitogens were weaker during pregnancy.

Conclusions

A reduced response to mitogens, with postdelivery normalization, was noted in a pregnant woman with an ARN syndrome. Further studies are needed to explore the antigen-specific immune deviation in pregnant patients with ARN.

Influence of an immunodominant herpes simplex virus type 1 CD8+ T cell epitope on the target hierarchy and function of subdominant CD8+ T cells

Herpes simplex virus type 1 (HSV-1) latency in sensory ganglia such as trigeminal ganglia (TG) is associated with a persistent immune infiltrate that includes effector memory CD8+ T cells that can influence HSV-1 reactivation. In C57BL/6 mice, HSV-1 induces a highly skewed CD8+ T cell repertoire, in which half of CD8+ T cells (gB-CD8s) recognize a single epitope on glycoprotein B (gB498-505), while the remainder (non-gB-CD8s) recognize, in varying proportions, 19 subdominant epitopes on 12 viral proteins. The gB-CD8s remain functional in TG throughout latency, while non-gB-CD8s exhibit varying degrees of functional compromise. To understand how dominance hierarchies relate to CD8+ T cell function during latency, we characterized the TG-associated CD8+ T cells following corneal infection with a recombinant HSV-1 lacking the immunodominant gB498-505 epitope (S1L). S1L induced a numerically equivalent CD8+ T cell infiltrate in the TG that was HSV-specific, but lacked specificity for gB498-505. Instead, there was a general increase of non-gB-CD8s with specific subdominant epitopes arising to codominance. In a latent S1L infection, non-gB-CD8s in the TG showed a hierarchy targeting different epitopes at latency compared to at acute times, and these cells retained an increased functionality at latency. In a latent S1L infection, these non-gB-CD8s also display an equivalent ability to block HSV reactivation in ex vivo ganglionic cultures compared to TG infected with wild type HSV-1. These data indicate that loss of the immunodominant gB498-505 epitope alters the dominance hierarchy and reduces functional compromise of CD8+ T cells specific for subdominant HSV-1 epitopes during viral latency.

Immune ring formation associated with cytomegalovirus endotheliitis

PURPOSE

To describe immune ring (IR) formation as a manifestation of cytomegalovirus (CMV) endotheliitis.

DESIGN

Retrospective observational case series.

METHODS

Review of all consecutive CMV anterior uveitis and endotheliitis patients seen at the Singapore National Eye Centre for the occurrence of an IR. CMV infection was diagnosed by polymerase chain reaction analysis of the aqueous.

RESULTS

None of the 72 eyes with CMV anterior uveitis had an IR formation. Four episodes of IR formation were seen in 3 eyes (14.3%) of 21 cases of CMV-positive endotheliitis. All were unilateral and all 3 patients were human immunodeficiency virus negative middle-aged Chinese males. The IR developed 2 to 7 months after occurrence of the endotheliitis and the aqueous was positive for CMV during 2 of the episodes of IR formation. In 2 eyes, the IR occurred at the completion of a course of systemic ganciclovir when the aqueous was negative for CMV. The immune rings resolved with combination therapy of topical prednisolone acetate 0.12% and ganciclovir. Patient 1 had a recurrence of the IR 4 months after stopping treatment but again resolved following treatment with ganciclovir and topical corticosteroids.

CONCLUSION

Corneal immune rings can occur as a result of CMV infection. Hence CMV infection may have to be considered in such cases.

Pattern recognition can detect subtle field defects in eyes of HIV individuals without retinitis under HAART

Objectives

To use machine learning classifiers (MLCs) to seek differences in visual fields (VFs) between normal eyes and eyes of HIV+ patients; to find the effect of immunodeficiency on VFs and to compare the effectiveness of MLCs to commonly-used Statpac global indices in analyzing standard automated perimetry (SAP).

Methods

The high CD4 group consisted of 70 eyes of 39 HIV-positive patients with good immune status (CD4 counts were never <100/ml). The low CD4 group had 59 eyes of 38 HIV-positive patients with CD4 cell counts <100/ml at some period of time lasting for at least 6 months. The normal group consisted of 61 eyes of 52 HIV-negative individuals. We used a Humphrey Visual Field Analyzer, SAP full threshold program 24-2, and routine settings for evaluating VFs. We trained and tested support vector machine (SVM) machine learning classifiers to distinguish fields from normal subjects and high and CD4 groups separately. Receiver operating characteristic (ROC) curves measured the discrimination of each classifier, and areas under ROC were statistically compared.

Results

Low CD4 HIV patients: with SVM, the AUROC was 0.790 ± 0.042. SVM and MD each significantly differed from chance decision, with p < .00005. High CD4 HIV patients: the SVM AUROC of 0.664 ± 0.047 and MD were each significantly better than chance (p = .041, p = .05 respectively).

Conclusions

Eyes from both low and high CD4 HIV+ patients have VFs defects indicating retinal damage. Generalized learning classifier, SVM, and a Statpac classifier, MD, are effective at detecting HIV eyes that have field defects, even when these defects are subtle.

Comparison of prevalence of dengue maculopathy during two epidemics with differing predominant serotypes

PURPOSE

To compare the prevalence of dengue maculopathy among patients hospitalized for dengue fever during a 2007 epidemic with its prevalence during the 2005 epidemic.

DESIGN

Cross-sectional observational study of consecutive patients hospitalized in two general hospitals with dengue fever during the dengue epidemic.

METHODS

A standard questionnaire on ocular history and symptoms was completed by all patients. Their near and distance vision, Amsler grid test results, and dilated fundal findings were recorded. Biochemical tests included dengue immunoglobulin M results, serum complement 3 level, platelet count, hematocrit, and transaminase levels. The main outcome measure was presence of dengue maculopathy. Risk factors were compared with the data from a 2005 study group. Dengue serotype results were obtained from population sampling.

RESULTS

None of 87 patients who had positive results for dengue immunoglobulin M in the 2007 study group had maculopathy, whereas it was seen in 10% of the 2005 group (P = .002). The patients in the 2005 study group were younger and were more likely to have high transaminase levels. In 2005, the predominant serotype was type 1, and in 2007 it was type 2.

CONCLUSIONS

The prevalence of dengue maculopathy, age of clinical disease, and extent of liver damage differs between epidemics with different predominant serotypes.

Analysis of HLA Class I and Class II Gene Polymorphisms in Japanese Patients with Human T-Cell Lymphotropic Virus Type 1-Associated Uveitis

PURPOSE

To investigate the immunogenetic background of human T-cell lymphotropic virus type 1 (HTLV-1)-associated uveitis (HAU) that presents immune-mediated reactive changes in the uvea.

METHODS

HLA class I and class II genes were studied in 51 patients with HAU, 192 asymptomatic HTLV-1 carriers, and 266 HTLV-1-seronegative controls using a high-resolution method of HLA DNA typing. The HLA alleles of HAU were compared with those of HTLV-1 carriers and healthy controls.

RESULTS

We identified 62 distinct alleles of HLA-A, HLA-Cw, and HLA-B and 49 distinct alleles of HLA-DRB1 and HLA-DQB1 in patients with HAU, asymptomatic HTLV-1 carriers, and healthy controls. The relative frequencies of these HLA alleles did not differ among the three groups.

CONCLUSION

The results suggest that HLA class I and class II genes do not contribute to susceptibility to HAU.

Introduction and immunopathogenesis of acquired immune deficiency syndrome

India has a large number of patients with acquired immune deficiency syndrome (AIDS), the third largest population of this group in the world. This disease was first described in patients with Pneumocystis pneumonia in 1981. Ocular lesions can occur at any stage of the disease but are more commonly seen at the late stages. Human immunodeficiency virus (HIV), the causative agent of AIDS is a retrovirus with RNA genome and a unique 'Reverse transcriptase enzyme' and is of two types, HIV-1 and 2. Most human diseases are caused by HIV-1. The HIV-1 subtypes prevalent in India are A, B and C. They act predominantly by reducing the CD4+ cells and thus the patient becomes susceptible to opportunistic infections. High viral titers in the peripheral blood during primary infection lead to decrease in the number of CD4+ T lymphocytes. Onset of HIV-1-specific cellular immune response with synthesis of HIV-1 specific antibodies leads to the decline of plasma viral load and chronification of HIV-1 infection. However, the asymptomatic stage of infection may lead to persistent viral replication and a rapid turnover of plasma virions which is the clinical latency. During this period, there is further decrease in the CD4+ counts which makes the patient's immune system incapable of controlling opportunistic pathogens and thus life-threatening AIDS-defining diseases emerge. Advent of highly active antiretroviral treatment (HAART) has revolutionized the management of AIDS though there is associated increased development of immune recovery uveitis in a few of these patients.

[Intraocular infection with herpesviruses and antiviral immunity in patients with age-related macular degeneration]

Polymerase chain reaction revealed Herpesviridae (Herpes simplex, Cytomegalovirus) in the lens substance in 46 patients operated on for age-related cataract. Thirty-two patients of them had age-related macular degeneration. Herpes simplex was found in 6 (18.8%) of the patients with age-related macular degeneration. At the same time there were signs of lacrimal fluid antiviral immunity imbalance with decreased IFN-gamma and TNF-alpha and increased IFN-alpha. The authors consider it advisable to perform antivirus treatment in patients with the above abnormality, preventing the active forms of herpetic infection.

Ocular involvement associated with an epidemic outbreak of chikungunya virus infection

PURPOSE

To study the range of ocular symptoms in a cohort of patients with chikungunya infection.

DESIGN

Retrospective, observational case series.

METHODS

Patients attending a tertiary eye care hospital in South India were included in the study. We included adult patients with serologically confirmed chikungunya virus infection who received clinical care at the Aravind Eye Hospital, Madurai, South India. They were assessed for demographic characteristics, ocular symptoms, laboratory parameters, and chikungunya virus infection severity. Patients underwent a complete ophthalmologic examination that included visual acuity, slit-lamp examination, and indirect funduscopic examination. Visual outcome at the end of three months was the main outcome measure.

RESULTS

The charts of 37 patients were analyzed based on the clinical picture and the serologic results. Forty patients were included as controls and tested negative. There were 21 males and 16 females with a mean age of 44.17 years. The main ocular symptoms included granulomatous and nongranulomatous anterior uveitis, optic neuritis retrobulbar neuritis, and dendritic lesions. Of the 26 patients who were followed up for three months, the visual acuity improved in 11 patients (42.3%), remained the same in 12 patients (46.15%), and worsened in three patients (11.5%).

CONCLUSIONS

The main ocular manifestation associated with the recent epidemic outbreak of chikungunya virus infection in South India included granulomatous and nongranulomatous anterior uveitis, optic neuritis, retrobulbar neuritis, and dendritic lesions. The visual prognosis generally was good, with most patients recovering good vision. Further studies are needed to understand the pathogenesis of this disease.

Rubella virus-associated uveitis in a nonvaccinated child

PURPOSE

To report presumed Fuchs heterochromic uveitis (FHU) associated with Rubella virus (RV)-specific intraocular antibody production in a child who was not vaccinated against rubella.

DESIGN

Observational case report.

METHODS

We examined a 13-year-old boy with chronic anterior uveitis complicated by mature cataract. Two aqueous humor (AH) samples taken with an interval of four weeks were analyzed for intraocular antibody production against RV by calculation of the Goldmann-Witmer coefficient.

RESULTS

The patient showed all the clinical signs for FHU: iris atrophy, stellate keratic precipitates, and cataract. Analysis of the AH demonstrated intraocular antibody production against RV in two sequential samples.

CONCLUSIONS

The data show that RV-associated uveitis can already present during childhood. Moreover, this finding suggests that nonvaccinated children may be at risk to develop uveitis after RV infection.

Th-cytotoxic T-lymphocyte chimeric epitopes extended by Nepsilon-palmitoyl lysines induce herpes simplex virus type 1-specific effector CD8+ Tc1 responses and protect against ocular infection

Molecularly defined vaccine formulations capable of inducing antiviral CD8+ T-cell-specific immunity in a manner compatible with human delivery are limited. Few molecules achieve this target without the support of an appropriate immunological adjuvant. In this study, we investigate the potential of totally synthetic palmitoyl-tailed helper-cytotoxic-T-lymphocyte chimeric epitopes (Th-CTL chimeric lipopeptides) to induce herpes simplex virus type 1 (HSV-1)-specific CD8+ T-cell responses. As a model antigen, the HSV-1 glycoprotein B498-505 (gB498-505) CD8+ CTL epitope was synthesized in line with the Pan DR peptide (PADRE), a universal CD4+ Th epitope. The peptide backbone, composed solely of both epitopes, was extended by N-terminal attachment of one (PAM-Th-CTL), two [(PAM)2-Th-CTL], or three [(PAM)3-Th-CTL] palmitoyl lysines and delivered to H2b mice in adjuvant-free saline. Potent HSV-1 gB498-505-specific antiviral CD8+ T-cell effector type 1 responses were induced by each of the palmitoyl-tailed Th-CTL chimeric epitopes, irrespective of the number of lipid moieties. The palmitoyl-tailed Th-CTL chimeric epitopes provoked cell surface expression of major histocompatibility complex and costimulatory molecules and production of interleukin-12 and tumor necrosis factor alpha proinflammatory cytokines by immature dendritic cells. Following ocular HSV-1 challenge, palmitoyl-tailed Th-CTL-immunized mice exhibited a decrease of virus replication in the eye and in the local trigeminal ganglion and reduced herpetic blepharitis and corneal scarring. The rational of the molecularly defined vaccine approach presented in this study may be applied to ocular herpes and other viral infections in humans, providing steps are taken to include appropriate Th and CTL epitopes and lipid groups.

[Ocular complications of dengue fever]

We report a case of a 32-year-old Danish woman with ocular complications of (IgM-verified) dengue fever. After having returned from a trip to Thailand, she became ill with fever and symptoms suggestive of dengue. On the tenth day, when the fever had subsided, she suddenly experienced visual disturbances and was admitted to hospital. Ophthalmologic examination revealed retinal oedema, probably immunologically mediated. Months later, her visual symptoms had still not completely disappeared. Ocular complications of dengue are rarely reported, but in the Third World they are probably common.

HIV-associated retinopathy in the HAART era

BACKGROUND

The effectiveness of highly active antiretroviral therapy (HAART) in restoring immune function in patients with acquired immunodeficiency syndrome (AIDS) has led to changes in the incidence, natural history, management, and sequelae of human immunodeficiency virus (HIV)-associated retinopathies, especially cytomegalovirus (CMV) retinitis.

METHODS

The medical literature pertaining to HIV-associated retinopathies was reviewed with special attention to the differences in incidence, management strategies, and complications of these conditions in the eras both before and after the widespread use of HAART.

RESULTS

In the pre-HAART era, CMV retinitis was the most common HIV-associated retinopathy, occurring in 20%-40% of patients. Median time to progression was 47 to 104 days, mean survival after diagnosis was 6 to 10 months, and indefinite intravenous maintenance therapy was mandatory. Retinal detachment occurred in 24%-50% of patients annually. Herpetic retinopathy and toxoplasmosis retinochoroiditis occurred in 1%-3% of patients and Pneumocystis carinii choroiditis, syphilitic retinitis, tuberculous choroiditis, cryptococcal choroiditis, and intraocular lymphoma occurred infrequently. In the HAART era the incidence of CMV retinitis has declined 80% and survival after diagnosis has increased to over 1 year. Immune recovery in patients on HAART has allowed safe discontinuation of maintenance therapy in patients with regressed CMV retinitis and other HIV-associated retinopathies. Immune recovery uveitis (IRU) is a HAART dependent inflammatory response that may occur in up to 63% of patients with regressed CMV retinitis and elevated CD4 counts and is associated with vision loss from epiretinal membrane, cataract, and cystoid macular edema.

CONCLUSIONS

The incidence, visual morbidity, and mortality of CMV retinitis and other HIV-associated retinopathies have decreased in the era of HAART and lifelong maintenance therapy may safely be discontinued in patients with restored immune function. Patients with regressed CMV retinitis, however, may still lose vision from epiretinal membrane, cystoid macular edema, and cataract secondary to IRU.

Involvement of IL-6 in the paracrine production of VEGF in ocular HSV-1 infection

Following ocular HSV-1 infection, neovascularisation of the avascular cornea is a critical event in the pathogenesis of herpetic stromal keratitis. This present study evaluates the role of proinflammatory cytokines such as IL-6 in corneal angiogenesis following virus infection. Both in vivo and in vitro data indicate that IL-6 produced from virus-infected cells can stimulate noninfected resident corneal cells and other inflammatory cells in a paracrine manner to secrete VEGF, a potent angiogenic factor. Antibody neutralisation of IL-6 resulted in a significant decrease in the number of VEGF producing cells in the cornea. Thus, our results further demonstrate the close relationship between proinflammatory cytokines and VEGF-induced corneal neovascularisation.

[Immunoprophylaxis versus immunotherapy in herpetic eye infections]

The preventive and curative treatment of the eye herpetic infections involves, besides the antiviral therapy, also different approaches which can stimulate the natural protective capacity of the human body (the antiherpetic vaccine and the immunomodulation agents).

Systemic and ocular antibody responses to inactivated acute hemorrhagic conjunctivitis (AHC) virus; enterovirus 70 (EV70)

PURPOSE

Evaluate the immune response in rabbits injected with EV70, the agent of acute hemorrhagic conjunctivitis (AHC) and AHC associated neuropathy.

METHODS

Rabbits were injected intramuscularly with uv-light inactivated EV70 isolate J670/71. Neutralizing activity against EV70 was quantified in serum and tear samples and the immunoglobulin (Ig) classes of the neutralizing activity in serum identified by sucrose gradient ultra-centrifugation. Adjuvant muramyl dipeptide (MDP) was applied topically to assess the role of ocular inflammation on levels of neutralizing antibody, proteins and Ig in tears. The protective effects of human and rabbit sera and interferon-alpha (IFN-alpha) against EV70 were compared in human conjunctival and lens cells.

RESULTS

Sera collected at 6 and 13 d contained 19S IgM anti-EV70 neutralizing antibody, while serum collected 21 d post injection contained 19S IgM and 7S IgG anti-EV70 neutralizing antibody. Low titers of anti-EV70 activity (< or =30 U/ml) were detected in tears of seropositive rabbits. MDP induction of conjunctivitis in seropositive rabbits increased tear IgG concentration (3-fold) and anti-EV70 neutralizing antibody titers (> or =10-fold). The protective effect of the rabbit and human sera against EV70 infection in conjunctival, but not lens epithelial cells, was enhanced by the addition of IFN-alpha.

CONCLUSIONS

Immunization with uv-light inactivated EV70 elicits a classical humoral immune response in rabbits. The protective activity of serum in EV70-infected human conjunctival cells, but not lens cells, was increased by IFN-alpha. Adjuvant MDP-induced conjunctivitis, increased blood-conjunctival barrier (BCB) permeability and anti-EV70 neutralizing activity in tear of seropositive rabbits. The results suggest immunization with inactivated EV70 could provide systemic as well as ocular protection during natural EV70 infection.

Loss of the perforin cytotoxic pathway predisposes mice to experimental cytomegalovirus retinitis

AIDS-related human cytomegalovirus (HCMV) retinitis continues to be a chronic ophthalmologic problem among human immunodeficiency virus type 1 (HIV-1)-infected patients who do not respond to highly active antiretroviral therapy. Although HCMV retinitis occurs during HIV-1-induced immunosuppression, the precise effector mechanism(s) that fails during the immunopathogenesis of AIDS to allow onset and progression of HCMV retinal disease remains unclear. We therefore performed a series of experiments to explore the relative roles of distinct pathways of lymphocyte-mediated cytotoxicity in either resistance or susceptibility to experimental murine cytomegalovirus (MCMV) retinitis in mice. Whereas mutant C57BL/6 mice deficient in the Fas/FasL cytotoxic pathway (gld mice) were identical to normal C57BL/6 mice and exhibited absolute resistance to retinal necrosis following subretinal MCMV inoculation, knockout C57BL/6 mice deficient in the perforin cytotoxic pathway (PKO mice) were susceptible to MCMV retinitis. Susceptibility of PKO mice to MCMV retinitis correlated with increased ocular MCMV titers when compared with ocular MCMV titers of gld and normal mice. Since mice with retrovirus-induced immunodeficiency syndrome (MAIDS) exhibited a frequency and severity of MCMV retinitis that were equivalent to those observed in PKO mice, we hypothesized that susceptibility to MCMV retinitis during MAIDS correlates with a decrease in the perforin cytotoxic pathway. To test this hypothesis, we developed a quantitative competitive reverse transcription-PCR assay to measure mouse perforin mRNA levels in the splenic T lymphocytes and MCMV-inoculated eyes of normal mice or mice with MAIDS. Perforin mRNA levels in splenic T lymphocytes were significantly decreased during MAIDS, by approximately 100-fold, from perforin mRNA levels in normal mice. Moreover, MCMV-inoculated eyes destined to develop retinitis during MAIDS also showed a significant decrease in perforin mRNA levels from the perforin mRNA levels of MCMV-inoculated eyes of normal mice destined to be resistant to retinitis. As expected, perforin mRNA could not be detected in unmanipulated and uninfected eyes of normal mice. These results provide the first evidence that the perforin cytotoxic pathway is more important than the Fas/FasL cytotoxic pathway in providing resistance to experimental MCMV retinitis and that loss of the perforin cytotoxic pathway predisposes to MCMV retinitis.

The diagnostic significance of enzyme linked immuno-sorbent assay for herpes simplex, varicella zoster and cytomegalovirus retinitis

PURPOSE

To evaluate the diagnostic usefulness of enzyme linked immuno-sorbent assay (ELISA) in single serum samples to associate herpes simplex virus (HSV), varicella zoster virus (VZV) or cytomegalovirus (CMV) with viral retinitis as against polymerase chain reaction (PCR) on intraocular specimens. It was also designed to study the seroprevalence in normal healthy individuals, and the genomic prevalence of HSV, VZV and CMV in patients without an active viral inflammatory process.

METHODS

PCR for the detection of HSV, VZV and CMV genomes was done on 33 and 90 intraocular fluids from viral retinal patients and non-viral controls respectively. ELISA was done on 30 and 100 serum samples from viral retinitis patients and normal healthy controls respectively.

RESULTS

PCR did not detect HSV, VZV and CMV genomes except one, in which VZV-DNA was detected. ELISA showed prevalence rates of 28%, 83% and 90% for antibodies against HSV, VZV and CMV respectively in the normal population. In the 30 viral retinitis patients, PCR detected HSV-DNA in 2 (6.7%), VZV-DNA in 7 (23.3%) and CMV-DNA in 6 (20.0%) patients, while ELISA detected antibodies against HSV, VZV and CMV in 13 (43.3%), 24 (80.0%) and 23 (76.7%) patients respectively. ELISA was of value in indirect diagnosis only in 6 (20.0%) as compared to 15 (50.0%) of 30 patients by PCR, this difference was statistically significant (McNemar test, P value = 0.005).

CONCLUSION

Serology by ELISA is no longer a useful diagnostic tool to associate HSV, VZV and CMV viruses with viral retinitis.

Herpes simplex virus infection of the human eye induces a compartmentalized virus-specific B cell response

Intraocular infection with herpes simplex virus (HSV) can cause uveitis, a potentially sight-threatening disease. The disease is characterized by an ocular infiltration of inflammatory cells such as macrophages and B and T cells. The characteristics of the local humoral and cellular immune responses elicited on intraocular HSV infection are poorly understood. The local HSV-specific antibody production, which are used routinely for confirmation of a clinical diagnosis of herpetic uveitis, has never been analyzed in detail. This study analyzed the humoral immune response against HSV type 1 (HSV-1) in paired samples of intraocular fluid and serum of patients with intraocular herpesvirus infection. In addition, the B cell epitope distribution on a single HSV-1 type-specific antigen, glycoprotein G, was compared for these paired samples. The results presented here indicate that the inflamed eyes of patients with HSV-induced uveitis display a compartmentalized B cell response directed toward the triggering virus.

Seropositivity of human herpesvirus-8 in patients with uveitis

PURPOSE

To explore the role of human herpesvirus-8 (HHV-8) in the pathogenesis of uveitis and other forms of ocular inflammation.

METHODS

Serum antibody titers to HHV-8 were measured in 76 patients with uveitis from various causes and other types of ocular inflammation in either the acute phase, the convalescent phase, or both.

RESULTS

Only one 21-year-old male patient in the convalescent phase of unilateral pars planitis showed a positive titer for HHV-8. His serum was negative for human immunodeficiency virus-1.

CONCLUSIONS

Although the seropositive rate in the patient population was higher than that in the general population, the increased incidence was not statistically significant. The role of HHV-8 in the pathogenesis of intraocular inflammation appears to be limited.

Herpes simplex virus type 2 as a cause of acute retinal necrosis syndrome in young patients

PURPOSE

To determine the causative virus in acute retinal necrosis (ARN) syndrome in a series of patients by calculation of modified Witmer coefficients.

DESIGN

Noncomparative case series.

PARTICIPANTS

Ten patients with ARN syndrome from four medical centers.

METHODS

Aqueous samples, vitreous samples, or both were collected prospectively during surgery from patients with a clinical diagnosis of ARN syndrome. Serologic measures of intraocular and serum antibodies to potentially causative viruses were measured by enzyme-linked immunosorbent assay.

MAIN OUTCOME MEASURES

Modified Witmer coefficients (immunoglobulin G and immunoglobulin A) for herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), varicella zoster virus (VZV), and cytomegalovirus (CMV), as well as adenovirus type 2, were calculated from aqueous or vitreous samples, or both.

RESULTS

Intraocular antibody measurements were strongly suggestive of a single diagnosis in 9 of 10 patients tested. Modified Witmer coefficients demonstrated intraocular antibody production to HSV in five patients and antibodies to VZV in four patients, and the measurement was inconclusive in one patient. No patients were positive for adenovirus or CMV. Strain-specific antibody titers demonstrated that all HSV-positive patients were reactive only to HSV-2. Herpes simplex virus type 2 was found predominantly in younger patients with ARN syndrome (mean age, 21.2 +/- 10 years; range, 17-39 years), whereas VZV was more commonly seen in older patients (mean age, 40.8 +/- 12.2 years; range, 29-58 years; P = 0.033). Immunoglobulin A testing confirmed immunoglobulin G testing in all patients examined.

CONCLUSIONS

Although VZV is thought to be the most common cause of ARN syndrome, HSV-2 is an important cause of ARN syndrome, particularly in younger patients. Because infection with HSV-2 has important medical ramifications, these results suggest that determination of a causal agent should be considered in some cases of ARN syndrome.

Rabies virus ocular disease: T-cell-dependent protection is under the control of signaling by the p55 tumor necrosis factor alpha receptor, p55TNFR

Following brain infection, the Challenge Virus Standard strain of rabies virus infects the retina. Rabies virus ocular infection induces the infiltration of neutrophils and predominantly T cells into the eye. The role of tumor necrosis factor alpha (TNF-alpha)-lymphotoxin signaling in the control of rabies virus ocular infection and inflammatory cell infiltration was assessed using mice lacking the p55 TNF-alpha receptor (p55TNFR(-/-) mice). The incidence of ocular disease and the intensity of retinal infection were greater in p55TNFR(-/-) mice than in C57BL/6 mice: the aggravation correlated with less neutrophil and T-cell infiltration. This indicates that cellular infiltration is under the control of the p55 TNF-alpha receptor and suggests that inflammatory cells may protect the eye against rabies virus ocular infection. The role of T cells following rabies virus ocular disease was assessed by comparison of rabies virus infection in nude mice with their normal counterparts. Indeed, the incidence and severity of the rabies virus ocular disease were higher in athymic nude mice than in BALB/c mice, indicating that T lymphocytes are protective during rabies virus ocular infection. Moreover, few T cells and neutrophils underwent apoptosis in rabies virus-infected retina. Altogether, these data suggest that T lymphocytes and neutrophils are able to enter the eye, escape the immune privilege status, and limit rabies virus ocular disease. In conclusion, rabies virus-mediated eye disease provides a new model for studying mechanisms regulating immune privilege during viral infection.

The role of apoptosis within the retina of coronavirus-infected mice

PURPOSE

To evaluate the possible roles of apoptosis in the murine retinopathy induced by coronavirus.

METHODS

Mice were inoculated with virus intravitreally. Mouse eyes harvested at varying times after inoculation were evaluated for apoptotic and immunologic events by hematoxylin and eosin staining, immunohistochemical staining, in situ terminal deoxynucleotidyltransferase dUTP nick-end labeling (TUNEL) assay, and electron microscopy. Isolated retinas were analyzed for infectious virus and for expression of apoptosis-associated genes.

RESULTS

The number of apoptotic events was significantly elevated in infected eyes from BALB/c and CD-1 mouse strains, reaching a maximum at days 6 through 10, and returning to normal levels at day 20. The majority of apoptotic cells were observed in the outer nuclear layer of the infected retina. In contrast, few apoptotic cells were observed in normal or mock-injected mouse eyes. Apoptotic events within the retina were associated with the presence of viral antigen, infiltration of CD8(+) T cells, and clearance of infectious virus. Reverse transcription-polymerase chain reaction (RT-PCR) analysis identified the upregulation of Fas ligand (FasL) and granzyme B mRNAs within the infected retinas. The development of apoptosis, regulative gene expression, and viral clearance were similar in both retinal degeneration-susceptible (BALB/c) and -resistant (CD-1) mice.

CONCLUSIONS

Retinal apoptosis was associated with retinal inflammation, a decrease in infectious virus, and upregulation of genes associated with CTL killing. These studies indicate that retinal apoptosis may be one of the host mechanisms that contribute to limiting this retinal infection.

Gamma interferon impedes the establishment of herpes simplex virus type 1 latent infection but has no impact on its maintenance or reactivation in mice

Murine models of gamma interferon (IFN-gamma) deficiency demonstrate the role of this cytokine in attenuating acute herpes simplex virus (HSV) disease; however, the effect of IFN-gamma on the establishment and maintenance of neuronal latency and viral reactivation is not known. Using the IFN-gamma knockout (GKO) model of IFN-gamma deficiency and sensitive quantitative PCR methods, we show that IFN-gamma significantly reduces the ganglion content of latent HSV-1 in BALB/c mice, which in turn delays viral time to reactivation following UV irradiation. Similar effects were not seen in the C57BL/6 strain. These results indicate that IFN-gamma significantly attenuates latent HSV infection in the mouse model of ocular infection but has no impact on the maintenance of latency or virus reactivation.

Intravitreal antiviral injections as adjunctive therapy in the management of immunocompetent patients with necrotizing herpetic retinopathy

PURPOSE

To report the use of intravitreal antiviral injections as adjunctive therapy in the management of three immunocompetent patients with necrotizing herpetic retinopathy.

METHOD

Case series.

RESULTS

Three patients with necrotizing herpetic retinopathy received intravitreal antiviral injections for treatment of progressive retinitis, despite standard intravenous acyclovir therapy. The retinitis resolved and visual acuity improved after a minimum of 6 months of follow-up in each case.

CONCLUSION

Intravitreal antiviral injections may be a safe and efficacious adjunctive therapy in the management of patients with necrotizing herpetic retinopathy.

Herpes simplex virus DNA identification from aqueous fluid in Fuchs heterochromic iridocyclitis

PURPOSE

To report the presence of herpes simplex virus DNA in the aqueous humor of an eye with Fuchs heterochromic iridocyclitis.

METHODS

In an eye with a clinical diagnosis of Fuchs heterochromic iridocyclitis, samples of aqueous humor and anterior capsule of the lens were obtained during cataract surgery. Polymerase chain reaction was performed on the samples to detect the presence of viral DNA including herpes simplex virus, varicella-zoster virus, and cytomegalovirus. Serologic analysis was also performed for antiviral immunoglobulins.

RESULTS

Herpes simplex virus DNA was identified in the aqueous humor but not in the anterior capsule. Serum immunoglobulin G was positive for herpes simplex virus, varicella-zoster virus, and cytomegalovirus.

CONCLUSIONS

The presence of herpes simplex virus DNA in the aqueous humor of an eye with Fuchs heterochromic iridocyclitis suggests that herpes simplex virus infection may play a role in the pathogenesis of Fuchs heterochromic iridocyclitis.

CD8(+) T cells can block herpes simplex virus type 1 (HSV-1) reactivation from latency in sensory neurons

Recurrent herpes simplex virus type 1 (HSV-1) disease usually results from reactivation of latent virus in sensory neurons and transmission to peripheral sites. Therefore, defining the mechanisms that maintain HSV-1 in a latent state in sensory neurons may provide new approaches to reducing susceptibility to recurrent herpetic disease. After primary HSV-1 corneal infection, CD8(+) T cells infiltrate the trigeminal ganglia (TGs) of mice, and are retained in latently infected ganglia. Here we demonstrate that CD8(+) T cells that are present in the TGs at the time of excision can maintain HSV-1 in a latent state in sensory neurons in ex vivo TG cultures. Latently infected neurons expressed viral genome and some expressed HSV-1 immediate early and early proteins, but did not produce HSV-1 late proteins or infectious virions. Addition of anti-CD8alpha monoclonal antibody 5 d after culture initiation induced HSV-1 reactivation, as demonstrated by production of viral late proteins and infectious virions. Thus, CD8(+) T cells can prevent HSV-1 reactivation without destroying the infected neurons. We propose that when the intrinsic capacity of neurons to inhibit HSV-1 reactivation from latency is compromised, production of HSV-1 immediate early and early proteins might activate CD8(+) T cells aborting virion production.

Intraocular antibody production in intraocular inflammation

BACKGROUND

The production of intraocular antibodies is considered a specific marker for active infectious uveitis. The aim of our study was to evaluate the diagnostic value of aqueous humor analysis in consecutive patients referred to a tertiary clinical center.

METHODS

We analyzed 91 paired aqueous humor/serum samples from 89 patients with intraocular inflammation. In 71 patients aqueous humor analysis was used as a positive or negative confirmation of the suspected cause, whereas in 18 patients the clinical diagnosis was completely uncertain. A modified micro-ELISA technique was used to detect intraocular IgG production against Toxoplasma gondii, varicella zoster virus, herpes simplex virus and cytomegalovirus. Statistical analysis was performed using the "Cohen's kappa" test.

RESULTS

Specific intra-ocular antibody production could be detected in 12 (66.7%) of 18 patients with uncertain diagnosis. Subsequently initiated therapy led to clinical improvement in 10 patients, whereas 2 patients remained unchanged. In 2 (2.8%) of 71 patients aqueous humor analysis led to revision of the initially suspected etiology and to a change of therapy. Statistical analysis showed a significant accordance of diagnosis and aqueous humor analysis (P<0.01).

CONCLUSION

In patients with infectious uveitis, analysis of intraocular synthesis of specific antibodies is a valuable tool to establish the etiology rapidly and allows initiation of targeted antimicrobial treatment.

Natural killer cells prevent direct anterior-to-posterior spread of herpes simplex virus type 1 in the eye

PURPOSE

Anterior chamber (AC) inoculation of the KOS strain of herpes simplex virus type 1 (HSV-1) results in morphologic sparing of the ipsilateral retina, whereas the retina of the uninoculated contralateral eye becomes infected and undergoes acute retinal necrosis. Natural killer (NK) cells are an important component of the primary immune response to most virus infections. The purpose of this study was to determine whether NK cells are involved in preventing early direct anterior-to-posterior spread of HSV-1 after AC inoculation.

METHODS

Normal BALB/c mice were inoculated with 4 X 10(4) plaque-forming units (PFU) of the KOS strain of HSV-1 using the AC route. NK activity was measured in the spleen, the superficial cervical and submandibular lymph nodes, and the inoculated eye by lysis of chromium-labeled, NK-sensitive YAC-1 target cells. Histopathologic scoring and immunohistochemical staining for HSV-1 were performed in NK-depleted (injected intravenously with anti-asialo GM1) or mock-depleted (injected intravenously with normal rabbit serum) mice.

RESULTS

In mock-depleted mice, NK activity in the spleens, superficial cervical and submandibular lymph nodes, and inoculated eyes peaked at postinoculation (pi) day 5 and declined by pi day 7. Treatment with anti-asialo GM1 eliminated NK activity in the eye and at nonocular sites. The histopathologic scores at pi day 5 indicated more damage to the retinas of NK-depleted mice than to those of mock-depleted mice, and immunohistochemical staining for HSV-1 showed spread of the virus to the sensory retina only in NK-depleted mice.

CONCLUSIONS

NK cells were activated within 5 days after AC inoculation of the KOS strain of HSV-1. Activation of NK cells appears to play a role in preventing direct anterior-to-posterior spread of the virus in the inoculated eye which, in turn, protects the retina of this eye and helps to explain why the architecture of the retina of this eye is spared.

Herpes simplex virus type 1 serum neutralizing antibody titers increase during latency in rabbits latently infected with latency-associated transcript (LAT)-positive but not LAT-negative viruses

The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation in the rabbit ocular model of HSV-1 latency and reactivation. LAT is also the only viral gene abundantly expressed during latency. Rabbits were ocularly infected with the wild-type HSV-1 strain McKrae or the McKrae-derived LAT null mutant dLAT2903. Serum neutralizing antibody titers were determined at various times during acute and latent infection. The neutralizing antibody titers induced by both viruses increased and were similar throughout the first 45 days after infection (P > 0.05). However, by day 59 postinfection (approximately 31 to 45 days after latency had been established), the neutralizing antibody titers induced by wild-type virus and dLAT2903 diverged significantly (P = 0.0005). The dLAT2903-induced neutralizing antibody titers decreased, while the wild-type virus-induced neutralizing antibody titers continued to increase. A rescuant of dLAT2903, in which spontaneous reactivation was fully restored, induced wild-type neutralizing antibody levels on day 59 postinfection. A second LAT mutant with impaired spontaneous reactivation had neutralizing antibody levels comparable to those of dLAT2903. In contrast to the results obtained in rabbits, in mice, neutralizing antibody titers did not increase over time during latency with any of the viruses. Since LAT is expressed in both rabbits and mice during latency, the difference in neutralizing antibody titers between these animals is unlikely to be due to expression of a LAT protein during latency. In contrast, LAT-positive (LAT(+)), but not LAT-negative (LAT(-)), viruses undergo efficient spontaneous reactivation in rabbits, while neither LAT(+) nor LAT(-) viruses undergo efficient spontaneous reactivation in mice. Thus, the increase in neutralizing antibody titers in rabbits latently infected with LAT(+) viruses may have been due to continued restimulation of the immune system by spontaneously reactivating virus.

AIDS related eye disease in Burundi, Africa

AIMS

To determine the prevalence of ocular manifestations in AIDS patients hospitalised in Bujumbura, Burundi, according to their CD4+ lymphocyte count, serological status for CMV and VZV, and general health status.

METHODS

Prospective study of 154 consecutive patients who underwent general and ophthalmological examinations, including dilated fundus examination. AIDS was diagnosed on the basis of Bangui criteria and HIV-1 seropositivity. CD4+ lymphocyte counts were determined by the Capcellia method. CMV and VZV antibodies were detected with ELISA methods.

RESULTS

The mean age was 37 (SD 9) years and 65% of the patients were male. Active tuberculosis was the most frequent underlying disease (61%). Almost all the patients (99%) were seropositive for CMV and VZV. Among the 115 patients for whom CD4+ lymphocyte counts were available, 86 (75%) had more than 100 cells x 10(6)/l. Ocular involvement comprised 16 cases of microangiopathy, six of opalescence of the anterior chamber, five of retinal perivasculitis, two of zoster ophthalmicus, two of viral retinitis, and one of opalescence of the vitreous.

CONCLUSION

In Africa, the prevalence of ocular involvement in HIV infection is far lower than in Europe and the United States, possibly because most African patients die before ocular opportunistic infections occur.

T cells specific for the triggering virus infiltrate the eye in patients with herpes simplex virus-mediated acute retinal necrosis

Acute retinal necrosis (ARN) is a rare, potentially blinding retinal disease resulting from ocular infections with herpes simplex virus (HSV) or varicella-zoster virus (VZV). To determine the antigen specificity and functional characteristics of ocular infiltrating T cells in ARN, T cells were isolated and expanded nonspecifically from intraocular fluid (IOF) samples from 2 patients with HSV-1- and 3 with VZV-mediated ARN. HSV-specific T cell reactivity could be detected only in the IOF-derived T cell lines (TCLs) of the 2 patients with HSV-mediated ARN. These TCLs consisted of both HSV type-common and type-specific CD4+ and CD8+ T cell clones (TCCs) with differential T cell receptor usage. Irrespective of their phenotype, the TCCs were cytolytic and secreted interferon-gamma, tumor necrosis factor-alpha, interleukin-4, and interleukin-5. In both patients, the antigen specificity of a substantial number of HSV-1-specific TCCs could be mapped to approximately 0.67-0.73 HSV-1 map units. The data presented suggest the contribution of T cells, specific for the triggering virus, to the pathogenesis of ARN.

Etiology of immune stromal (interstitial) keratitis

PURPOSE

We compared the etiologies of immune stromal keratitis (ISK), also known as interstitial keratitis (IK), in a recent group of patients with active and inactive ISK.

METHODS

We reviewed the charts of 97 patients seen in the cornea clinic at the University of Minnesota from 1985 through 1994. Fifty-five patients were classified as having active ISK, defined by stromal inflammation without ulceration within 1 year of presentation. Forty-two patients were identified as having inactive ISK, defined by evidence of past stromal inflammation including stromal scarring, stromal thinning, ghost vessels, and reduplication of Descemet's membrane without active inflammation for the 1 year before presentation. We determined the etiology of the ISK by careful review of the patient's ocular examination, as well as medical and laboratory workup. Patients were labeled with the diagnosis of idiopathic ISK if no identifiable etiology was found.

RESULTS

Herpes simplex virus (HSV) accounted for 71.4% of unilateral active ISK. Idiopathic accounted for 14.3%, and varicella-zoster virus accounted for 8.6% in this group. HSV was the etiologic factor of 50.0% of inactive unilateral cases, whereas 33.3% were idiopathic. Sixty percent of cases of bilateral, active ISK were from idiopathic causes. Syphilis was the cause of 48.5% of bilateral inactive cases. In this group, 33.3% were from idiopathic causes.

CONCLUSION

Although syphilis has been recognized for many years as the cause of 90% of cases of ISK, this is no longer true. We demonstrated that active ISK is most commonly caused by HSV or is idiopathic and that, although syphilis is the leading cause of inactive, bilateral ISK, it is responsible for only 18.6% of total cases.

T cells in the uninjected eye after anterior chamber inoculation of herpes simplex virus type 1

PURPOSE

To investigate T cell infiltration in the posterior segment of the uninjected eye after uniocular anterior chamber inoculation of HSV-1.

METHODS

The anterior chamber of one eye of euthymic BALB/c mice was injected with 1 x 10(4) plaque-forming units (PFU) to 2 x 10(4) PFU of herpes simplex virus type 1 (HSV-1; KOS strain). All mice were examined for retinitis on day 8 postinoculation (p.i.). Only mice with retinitis were retained and used in these experiments. Animals were killed on days 9, 11, 14, 21, 35, and 63 p.i. The uninjected eyes were removed. Some of the uninjected eyes were sectioned and stained for CD4+ and CD8+ cells using the avidin-biotinylated enzyme complex method. Infiltrating cells were collected from the remaining uninoculated eyes and stained using rat anti-mouse monoclonal antibodies specific for CD4+ or CD8+ T cells, and the percentage of CD4+ and CD8+ T cells was determined by flow cytometry.

RESULTS

At day 9 p.i. (acute retinitis), T cells were observed in the uvea but not in the retina of the contralateral eye. CD4+ and CD8+ cells were observed in the sensory retina coincident with the onset of retinal necrosis (day 11 p.i.), and CD4+ and CD8+ T cells continued to be detected in the remnants of the retina up to and including day 63 p.i. The maximum percentage of both CD4+ and CD8+ T cells was observed at day 21 p.i.

CONCLUSIONS

These results demonstrate that T cells enter the retina of the uninoculated eye during HSV-1 infection. The observation that T cells arrive in the sensory retina at the onset of retinal necrosis and not during acute retinitis and the peak of virus replication provides further evidence that T cells play a role in development of retinal necrosis. The result that T cells are observed in the uninjected eye as late as day 63 p.i. suggests that T cells might also have a role in the resolution phase of the disease.

Spread of HSV-1 to the suprachiasmatic nuclei and retina in T cell depleted BALB/c mice

Following uniocular anterior chamber inoculation of the KOS strain of HSV-1 in euthymic BALB/c mice, virus spreads from the injected eye to the brain, and from the brain to the optic nerve and retina of the uninjected eye by day 7 post inoculation (p.i.), but the optic nerve and retina of the injected eye are not infected with virus. Infection of the optic nerve and retina of the injected eye is observed only in athymic mice or in mice depleted of both CD4+ and CD8+ T cells. To determine the role of T cells in virus spread, adult female BALB/c mice were thymectomized and T cell depleted. Mice were co-injected with the KOS strain of HSV-1 and RH116, a thymidine kinase-negative mutant of KOS containing the Escherichia coli lac Z gene. Animals were sacrificed on days 3-7 p.i., and the eyes and brains were examined for blue-stained, virus-infected cells. A difference in the timing of virus infection was observed in the area of the suprachiasmatic nuclei only in mice depleted of both CD4+ and CD8+ T cells, and in this group, the contralateral suprachiasmatic nucleus was infected two days earlier. Since one route by which virus could infect the retina of the injected eye is via connections of the contralateral suprachiasmatic nucleus to the ipsilateral optic nerve, these findings suggest that (a) retinitis observed in the injected eyes of mice depleted of both CD4+ and CD8+ T cells results from virus infection of the contralateral suprachiasmatic nucleus followed by spread of virus to the ipsilateral optic nerve and retina and (b) early HSV-1 infection of the contralateral suprachiasmatic nucleus is prevented by a T cell dependent mechanism.

Necrotizing herpetic retinopathies. A spectrum of herpes virus-induced diseases determined by the immune state of the host

PURPOSE

Necrotizing herpetic retinopathies (NHR), a new spectrum of diseases induced by viruses of the herpes family (herpes simplex virus, varicella-zoster virus and cytomegalovirus), includes acute retinal necrosis (ARN) occurring in apparently immunocompetent patients and progressive outer retinal necrosis (PORN) described in severely immuno-compromised patients. Signs of impaired cellular immunity were seen in 16% of ARN patients in a review of 216 reported cases, indicating that immune dysfunction is not only at the origin of PORN but might also be at the origin of ARN. The aim of this study was to correlate clinical findings in NHR patients with their immunologic parameters.

METHODS

Charts from patients with the diagnosis of ARN or PORN seen from 1990 to 1995 were reviewed. Clinical characteristics and disease patterns were correlated with immunological parameters taking into account CD4 lymphocyte rate in AIDS patients and blood-lymphocyte subpopulation determination by flow cytometry, cutaneous delayed type hypersensitivity testing and lymphocytic proliferation rate to seven antigens in HIV-negative patients.

RESULTS

During the period considered, 11 patients and 7 patients fulfilled the criteria of ARN and PORN respectively. Immune dysfunctions were identified in most patients. Mild type of ARN and classical ARN were associated with discrete immune dysfunctions, ARN with features of PORN was seen in more immunodepressed patients and classical PORN was always seen in severely immunodepressed HIV patients.

CONCLUSION

Our findings suggest that NHR is a continuous spectrum of diseases induced by herpes viruses, whose clinical expression depends on the immune state of the host going from mild or classical ARN at one end in patients with non-detectable or slight immune dysfunction to PORN in severely immunodepressed patients at the other end and with intermediary forms between these extremes.

Improved impression cytology techniques for the immunopathological diagnosis of superficial viral infections

BACKGROUND

For epidemiological and therapeutic reasons early diagnosis of superficial viral infections is crucial. Conventional microbiological techniques are expensive, time consuming, and not sufficiently sensitive. In this study impression cytology techniques were evaluated to analyse their diagnostic potential in viral infections of the ocular surface.

METHOD

A Biopore membrane device instead of the original impression cytology technique was used to allow better quality and handling of the specimens. The impressions were processed, using monoclonal antibodies and immunoperoxidase or immunofluorescence techniques to assess the presence of herpes simplex virus, varicella zoster virus, or adenovirus antigens. Ocular surface specimens from healthy individuals (n = 10) and from patients with suspected viral surface disease (n = 19) were studied. Infected and non-infected cell cultures served as controls.

RESULTS

This modified technique of impression cytology allowed the collection of large conjunctival and corneal epithelial cell layers with excellent morphology. Immunocytological staining of these samples provided diagnostic results for all three viruses in patients with viral surface disease.

CONCLUSIONS

The use of Biopore membrane devices for the collection of ocular surface epithelia offers new diagnostic possibilities for external eye diseases. Immunopathological methods that are applied directly on these membrane devices can provide virological results within 1-4 hours. This contributes considerably to the clinical management of patients with infectious diseases of the ocular surface.

[Persistence of ophthalmotropic enteroviruses in ocular tissues after enterovirus uveitis]

Thirteen monkeys were infected with ophthalmotropic strains of ECHO11 and ECHO19 in the anterior chamber of one eye. Echovirus antigens were detected by direct immunofluorescence in the membranes of the infected and paired eyes in various periods after inoculation (from 3 days to 5 years 8 months). Virus antigen was detected both in the infected and intact eyes. During the acute period of uveitis the antigen was detected mainly in the anterior segment of the infected eye, whereas in remote period it was found mainly in the posterior segment. Long persistence of the virus antigen in various ocular membranes may explain many of the late complications observed in children with enterovirus uveitis.

Immunologic and virologic characterization of the primary infiltrating cells in the aqueous humor of human T-cell leukemia virus type-1 uveitis. Accumulation of the human T-cell leukemia virus type-1-infected cells and constitutive expression of viral and interleukin-6 messenger ribonucleic acids

PURPOSE

To characterize immunologically and virologically the infiltrating cells in the aqueous humor of patients with human T-cell leukemia virus type-1 (HTLV-1) uveitis (HU).

METHODS

With their informed consent, patients had 0.1 ml of the aqueous humor in the anterior chamber collected with a needle under an operating microscope. An aliquot of the collected sample from patients without steroid therapy was examined by May-Giemsa staining and immunocytochemically. The presence of the HTLV-1-infected cells was investigated by polymerase chain reaction (PCR) using the gag and pol regions of the provirus genome. The population of the infected cells was compared by PCR testing the amplification of the virus genome from 60 cells, or determining the endpoint of successful amplification of the twofold dilution series of the samples, collected from the aqueous humor and peripheral blood mononuclear cells (PBMCs), which were obtained at the same time. Expression of viral and cytokine genes was studied by reverse transcriptase-PCR (RT-PCR). The interleukin-6 (IL-6) level in the aqueous humor of patients with HU and control subjects was measured by a high-sensitivity enzyme-linked immunosorbent assay kit.

RESULTS

The number of the infiltrating cells ranged from 475 to 3563 (mean = 2111) per 0.1 ml of aqueous humor, and all the identifiable cells were lymphocytes. Most of them were CD3-positive T cells (mean = 78%), whereas CD4-positive cells constituted less than half (mean = 35.3%). HTLV-1 provirus was detected by PCR in the infiltrating cells of 36 of 38 patients with HU tested, whereas it was detected in 1 of 4 seropositive patients with other entities of uveitis. A higher population of the infected cells in the aqueous humor than in the PBMC was found in seven of nine patients with HU by two independent approaches. Expression of HTLV-1 env or pX genes or both was shown in all 12 patients with HU tested by RT-PCR. IL-6 messenger ribonucleic acid (mRNA) was detected by RT-PCR in 10 of these 12 patients, whereas those of interleukin-1 alpha, interleukin-2, interleukin-4, and tumor-necrosis factor-alpha were not, and that of interferon-gamma was detected in only 1 patient. The IL-6 level was elevated significantly in the aqueous humor of nine patients with HU compared with that of five control subjects (520.2 +/- 841 pg/ml versus 2.77 +/- 1.59 pg/ml, P < 0.01 by Mann-Whitney test).

CONCLUSIONS

HU is characterized by lymphocytic infiltration with a predominance of T cells and by the presence and probable accumulation of HTLV-1-infected lymphocytes in the affected eye. Production of viral antigens and IL-6 by the infiltrating cells could be responsible for the development of HU.

Adoptive transfer of murine cytomegalovirus-immune lymph node cells prevents retinitis in T-cell-depleted mice

PURPOSE

The purpose of this study was to determine whether adoptive transfer of murine cytomegalovirus (MCMV)-immune lymph node cells prevents retinitis in immunosuppressed mice.

METHODS

Adult BALB/c mice were thymectomized and T-cell depleted using rat monoclonal antibodies specific for mouse CD4+ and CD8+ T-cells. The level of rat immunoglobulin G in the treated mice was monitored by enzyme-linked immunosorbent assay. Immune cells were labeled with PKH26-GH immediately before adoptive transfer, and flow cytometry was used to determine the percentage of adoptively transferred T-cells (PKH+, fluorescein isothiocyanate [FITC+]) in the spleens of the recipient mice 3 days after transfer. The ability of adoptively transferred cells to protect from retinitis was studied in T-cell-depleted mice injected with MCMV through the supraciliary route. Mice received 4 x 10(7) in vitro-restimulated MCMV-immune cells, 4 x 10(7) freshly isolated MCMV-immune cells, 4 x 10(7) freshly isolated ovalbumin-immune cells, or no cells (control group).

RESULTS

The best time to balance depletion of endogenous T-cells with persistence of transferred cells was 3 weeks after T-cell depletion. Both restimulated and freshly isolated MCMV-immune cells conferred protection from retinitis. Freshly isolated ovalbumin-immune lymph node cells did not prevent retinitis, indicating that protection was virus-specific and merely was not because of transfer of antigen-activated lymph node cells.

CONCLUSIONS

Adoptive immunotherapy has been used to prevent cytomegalovirus (CMV) infection in patients who have undergone transplantation, and, by extrapolation, the results of these studies suggest that adoptive immunotherapy with human CMV-specific immune cells might be used to prevent or ameliorate CMV retinitis in immunocompromised patients.

Local immune responses in ocular virus infection and their implications for future immunotherapy

The ability of a human ocular system to recognize viruses as foreign and eliminate them is critical for the preservation of sight. Upon viral infection, the prevention of attachment and invasion on the ocular surface decreases the likelihood of their causing disease. The tear film, secretory IgA, cytokines, cellular specific and nonspecific immune mechanisms that act at the mucosal surface constitute the first line of defense. However, sight-threatening immunopathology can take place after these reactions. Possible immune intervention in these processes is discussed.

Reactivation of herpes simplex virus type 1 in the mouse trigeminal ganglion: an in vivo study of virus antigen and immune cell infiltration

The corneas of latently infected mice were UV irradiated to induce reactivation of herpes simplex virus type 1 (HSV-1) in the trigeminal ganglion (TG). On days 1 to 4 after irradiation, TG were removed, serially sectioned and double stained to identify immune cells and virus antigens. Virus antigen was detected in small numbers (most commonly one) of neurons per ganglion as early as day 1, confirming the rapidity of reactivation and the neuron as the likely site of this event. The immune response was also rapid and effective since virus antigen was identified in immune cells at day 1 and by day 4 all samples were negative. The predominant infiltrating cells on days 1 and 2, when virus antigen was present and being cleared, were T cells, both CD4+ and CD8+. Later, large numbers of B cells appeared, suggesting that local antibody production may also be involved in controlling the reactivated infection. The observations suggest that a significant proportion of reactivation events do not result in disease of the eye or shedding of virus in the tear film. However, they also suggest that as little as one reactivating neuron in the ganglion may be sufficient to lead to such disease and/or shedding.

T-cell subsets and T-cell receptor V beta utilization by Igh-1-congenic mice in herpetic retinal necrosis

BACKGROUND

After unilateral anterior chamber (AC) inoculation with herpes simplex virus type 1 (HSV-1), C.B-17 and BALB/c congenic mice, which differ only in a limited region around the lgh-1 locus on chromosome 12, show a striking difference in susceptibility to development of encephalitis and contralateral necrotizing chorioretinitis.

METHODS

After AC inoculation with HSV-1 (KOS), C.B-17 and BALB/c mice were followed up for the clinical signs of encephalitis and chorioretinitis. At different time points following inoculation, lymphocytes isolated from the spleen were triple-stained with antibodies directed against CD4 or CD8, IL-2R, and various V beta T-cell receptor (TCR) subsets, and were analyzed by flow cytometry.

RESULTS

These lgh-1-disparate congenic mice showed differences in the time course of splenic V beta T-cell receptor (TCR) usage in both CD4+, IL-2R+ and CD8+, IL-2R+ T cells. By day 1 post infection (p.i.), C.B-17 mice showed an increase of V beta 8 and V beta 9 TCR by both CD4+, IL-2R+ and CD8+, IL-2R+ splenic T cells. Susceptible BALB/c mice delayed the increase of splenic V beta 8 and V beta 9 TCR by CD4+, IL-2R+ T cells, which was noted by day 4 p.i. Furthermore, in BALB/c mice the usage of V beta 9 by CD8+ cells was increased by day 6 p.i.

CONCLUSIONS

Our findings indicate that early preferential splenic usage of a restricted repertoire of TCR occurs after ocular inoculation with HSV-1 in resistant C.B-17 mice. Such preferential TCR usage by activated T cells may prevent viral replication in the brain and contralateral eye and may be linked to protection from development of encephalitis and destructive herpesmediated ocular inflammation.

Pathogenesis of ocular cytomegalovirus infection in the immunocompromised host

Balb/C nude and C.B-17 SCID mice were inoculated with salivary gland passaged cytomegalovirus (SG-MCMV) intraperitoneally. Dissemination of the virus in the systemic and ocular tissues was studied by the direct immunofluorescence test, and the virus growth in each tissue was titrated in mouse embryonic fibroblasts. The mode of viral spread was assessed by inhibiting macrophage function by silica and administering polyclonal murine anti-MCMV antibody in the circulation. The virus first reached the eyelid, conjunctiva, and cornea. Subsequently, it spread in the outer ocular muscles and chorioretinal layer. Ocular tissues were involved as part of a generalized infection. Abrogation of macrophage function by silica did not affect the outcome of the viral distribution. Administration of antibody prior to and 3 days after the viral infection prevented virus dissemination. Ocular CMV infection occurred initially at the anterior segment of the eye in an immunocompromised host. Free virus, not macrophage-bound virus, disseminated via the bloodstream.