Cytomegalovirus retinitis in the acquired immunodeficiency syndrome (AIDS). Light-microscopical, ultrastructural and immunohistochemical examination of a case

Triple retinal infection with human immunodeficiency virus type 1, cytomegalovirus, and herpes simplex virus type 1. Light and electron microscopy, immunohistochemistry, and in situ hybridization

PURPOSE

This report describes the histopathologic and virologic findings of the retina from a 55-year-old bisexual patient with the acquired immune deficiency syndrome (AIDS), who had concurrent human immunodeficiency virus type 1 (HIV-1), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) retinitis, and was treated with ganciclovir.

METHODS

The eyes were obtained at autopsy and processed for light microscopy and transmission electron microscopy. Immunohistochemical stains for HSV-1, CMV, HIV-1, varicella zoster virus, and glial fibrillary acidic protein were carried out using the peroxidase-antiperoxidase and streptavidin-biotin-alkaline phosphatase techniques. For in situ hybridization, a radiolabeled CMV DNA probe (Eco-RI-Y fragment of strain AD 169) was used.

RESULTS

Results of histopathologic examination showed a full-thickness necrotizing retinitis with cytomegalic and herpes viral intranuclear inclusions in cells of the neurosensory retina, retinal vascular endothelium, and the retinal pigment epithelium. Some areas of the retina were replaced by glial tissue. The choroid contained only a few chronic inflammatory cells. Immunoperoxidase studies disclosed CMV antigens diffusely distributed throughout all layers of the retina and the retinal pigment epithelium. Herpes simplex virus type 1 antigens were present in retinal cells and the retinal vascular endothelium. Human immunodeficiency virus type 1 antigens were found in mononuclear cells in all layers of the sensory retina. Dual infections with HIV-1 and CMV of individual multinucleated giant cells of glial origin were demonstrated immunohistochemically. Transmission electron microscopy showed herpes viral particles in the vascular endothelium of the retinal vessels and the choriocapillaris. Human immunodeficiency virus particles were identified in the endothelium of the choriocapillaris.

CONCLUSIONS

The possibility of multiple viral infections of the retina, mimicking classic CMV retinitis, should be considered in the clinical and histologic differential diagnosis of necrotizing retinitis in patients with AIDS.

Systemic viral infections and their retinal and choroidal manifestations

Viruses are one of the most common causes of infections involving the posterior segment of the eye. Such infections can occur either on a congenital or an acquired basis, and may affect primarily the retina or the choroid. Congenital cytomegalovirus (CMV) and rubella infections may result in retinitis. CMV retinitis is also the most common cause of acquired viral retinitis, primarily because of the acquired immunodeficiency syndrome (AIDS). Other types of viral retinitis, such as those caused by herpes simplex or herpes zoster, can occur in immunocompromised or immunocompetent individuals. Retinitis or choroiditis caused by viruses such as measles, influenza, Epstein-Barr virus, and Rift Valley fever virus, typically occurs subsequent to an acute viral systemic illness. The systemic and ocular manifestations, as well as the histopathology, laboratory tests, differential diagnoses, and treatment regimens for each of the individual viruses are discussed in detail.

Cytomegalovirus infection of the larynx in the acquired immunodeficiency syndrome

CMV is the most important viral opportunist in patients with AIDS. Nearly all patients with AIDS have been exposed to CMV and the virus can be isolated from many. When CMV-related disease occurs in AIDS, it has usually involved the eye or gastrointestinal tract. In lesions in which CMV is the suspected etiology, evidence of direct pathogenicity of the virus should be obtained, usually histologically. Accurate diagnosis is essential because long-term therapy with a relatively toxic drug (ganciclovir) is indicated. We have presented a case of CMV infection of the larynx that responded, albeit slowly, to ganciclovir. Additional cases may arise as the prevalence of AIDS increases. Because of the potential for airway compromise and the tendency toward chronicity, CMV infection of the larynx should be of a significant concern both for the patient and the otolaryngologist.

Retinitis in euthymic mice following inoculation of murine cytomegalovirus (MCMV) via the supraciliary route

Cytomegalovirus (CMV) retinitis is the most frequent infectious ocular complication of the acquired immune deficiency syndrome (AIDS). Currently, there are few animal models to study the virologic and immunologic factors which contribute to the pathogenesis of CMV retinitis. In these experiments, 1-2 X 10(4) PFU of murine cytomegalovirus (MCMV) was inoculated into the supraciliary space of BALB/c mice. Within three days of inoculation, moderate iridocyclitis was observed which progressed to necrosis of the ciliary body by day 14. Approximately 60% of the mice developed typical retinitis characterized by virus-infected cytomegalic cells in the retina and retinal pigment epithelium, focal retinal infiltrates, transition zones between uninvolved and involved retina, and optic neuritis. The remaining animals exhibited atypical retinitis characterized by non-specific retinal inflammation in the absence of obvious viral infection. This murine model of CMV retinitis shares some features with retinitis observed in AIDS patients with CMV retinitis and may be useful to evaluate the efficacy of immunologic and/or pharmacologic treatment strategies for CMV retinitis.

Cytomegalovirus retinitis

Cytomegalovirus retinitis is a frequent and serious complication of various conditions, including diseases characterized by impaired immunity, such as the acquired immunodeficiency syndrome. Due to recent advances in the treatment of cytomegalovirus retinitis, accurate diagnosis and management have become increasingly important. In this review, the authors present the epidemiology, clinical features, diagnostic testing, treatment with complications, and prognosis of cytomegalovirus retinitis. A differential diagnosis is presented and the characteristic ocular lesions are illustrated.

Pathology of brain and eye in the acquired immune deficiency syndrome (AIDS). A comparison of lesions in a consecutive autopsy material

During the years 1984-1987, a consecutive Danish autopsy material of 43 AIDS cases was analysed in order to investigate a possible coincidence of pathological changes in brain and eye. In the brain, nodular gliosis/encephalitis was most frequent, followed by cytomegalovirus infection, which occurred twice as frequently as toxoplasmic infection and four times as frequently as fungal infection. In the eye, cytomegalovirus infection was most frequent and the only opportunistic infection, followed by retinal gliosis and cytoid body lesion. Malignant lymphoma was present in the brain in three patients, and in the choroid in two of these. In 11 patients, no changes of the brain were found. In eight of these the eye was also without pathological findings, while three had minor changes. In 22 patients the eye was normal, but in only eight of these was the brain without changes. Eight had nodular gliosis, and four a specific infection, while multifocal leucoencephalopathy and unspecified abscess each occurred in one patient. Comparison of the three opportunistic infections--CMV, toxoplasmosis and mycosis--in the three-year period showed an overall decreasing frequency, attributed to better medical care. It is concluded that concomitance of identical pathological lesions in brain and eye is less frequent than was expected.

Viral infections in the acquired immunodeficiency syndrome

The following communication is a tripartite synopsis of the role of viral infection in the acquired immunodeficiency syndrome (AIDS). The first section describes the impact of viral opportunistic infection in AIDS; for each virus, clinical presentation and diagnosis, laboratory diagnostic approaches (with emphasis on electron microscopy), and therapeutic interventions attempted to date are discussed. The second segment explores current theories on the pathogenesis of AIDS, and describes diagnostic and therapeutic approaches to the syndrome itself. The final section catalogues ultrastructural anomalies in the cells of AIDS patients, many of which have been mistakenly identified as etiologic agents.

Acquired immunodeficiency syndrome (AIDS)

The Acquired Immunodeficiency Syndrome (AIDS), caused by the human immunodeficiency virus (HIV), also called the human T-lymphotropic virus type III/lymphadenopathy-associated virus [HTLV-III/LAV], has affected over 23,000 people; more than half of those with the disease have died. The actual case fatality rate approaches 100%. AIDS affects all groups and classes of people, although some are at special risk. Distribution of the disease is worldwide. The illness' effects on the body are widespread; of special interest are the ophthalmologic manifestations. The eye may be infected by various viruses (cytomegalovirus, varicella-zoster virus, herpes simplex virus or HIV itself), toxoplasma gondii, candida sp, cryptococcus neoformans, M. tuberculosis, or M. avium-intracellulare. Kaposi's sarcoma may affect the eye as well. Retinal vascular abnormalities (e.g., cotton-wool spots, vasculitis) are not uncommon in AIDS. The syndrome may present with neuro-ophthalmologic manifestations. No effective treatment for the illness is currently available, although several hold promise and there is hope for an AIDS vaccine. Prevention of infection through reduction of risks appears to be the only defense against AIDS at this time.