Concurrent herpes simplex and cytomegalovirus retinitis and encephalitis in the acquired immune deficiency syndrome (AIDS)

We present a case of bilateral herpes simplex and cytomegalovirus retinitis and concurrent encephalitis following acyclovir therapy in a homosexual male with the acquired immune deficiency syndrome (AIDS). At autopsy, herpes simplex virus antigens were readily detected in all retinal layers, retinal pigment epithelium, and choriocapillaris, using an immunoperoxidase technique, whereas herpes simplex antigens in the brain were localized in restricted foci of vascular and subependymal parenchymal cells. Cytomegalovirus antigens were identified in cells in all layers of retina, in retinal pigment epithelium, and in subependymal parenchymal cells in the brain. No cytomegalovirus antigens were detected in any vascular endothelium, in choroid, or anterior to the ora serrata. The widespread expression of herpes simplex virus antigens in this patient's retinas is in marked contrast to the restricted foci of herpes simplex antigens limited to the subependymal region of the brain, and is similar to that seen in murine models of herpes simplex retinitis produced by acyclovir-resistant viral mutants.

Cyclosporin A treatment for chronic uveitis associated with retinitis

A chronic bilateral non-granulomatous uveitis triggered by a chlamydial infection developed in a patient with HLA-B 27. Cyclosporin A was administered as an ultimate remedy. It had a rapid curative effect against the inflammation. Probable cytomegalovirus (CMV) retinitis, however, was observed 2 months after the onset of this treatment. Retinitis healed after discontinuation of Cyclosporin A therapy.

Immunologic insights into uveitis and retinitis: the immunoregulatory circuit

The immune response is a complex series of cellular interactions, which is controlled by several regulatory mechanisms to insure an appropriate response. One of the most important mechanisms of control is the suppressor T cell immunoregulatory circuit. The immune response is presented in detail and examined from three different perspectives: 1) a clinical disease in which it is markedly abnormal--namely, the acquired immune deficiency syndrome or AIDS, 2) a clinical disease in which no systemic abnormality is apparent but where a local derangement in immunoregulation may be important--namely, idiopathic uveitis, and 3) a situation in which it is purposefully altered by medications for therapeutic purposes. Three drugs currently used in the treatment of uveitis--prednisone, cyclophosphamide, and cyclosporine--will be examined and compared.

Sindbis virus-induced ocular immunopathology

The intraocular injection of the Sindbis virus in adult BALB/c mice produces a uveoretinitis with little or no central nervous system involvement. Ocular disease starts on the third day after infection and presents as a mild to moderate iridocyclitis and retinitis, usually accompanied by typical severe dysplastic changes of the retina. The inflammatory infiltrate consists almost exclusively of lymphocytes and histiocytes. Immunosuppression of the mouse with cyclophosphamide on the day after infection markedly reduces or eliminates completely the inflammatory response, suggesting that the virus itself is not cytopathogenic. In the normal host, the virus replicates within the eye for several days but is then completely eliminated by day 8 after infection. In the immunosuppressed animal, virus titers reach greater levels than in the normal animal and then fall, in step with the developing inflammatory response. It would appear that the immunologic mechanisms responsible for clearance of the viral infection from the eye also mediate the ocular disease.

Acute rubella retinal pigment epitheliitis in an adult

A 50-year-old man who had been taking betamethasone for 20 days experienced a slight bilateral decrease in visual acuity. There were localized dark-gray atrophic lesions at the posterior pole, accompanied by a diffuse detachment of the sensory retina. The retinal vessels appeared to be normal and only minimal anterior uveitis was present in the more severely affected eye. Fluorescein angiograms showed no masking of choroidal fluorescence in the early phase and late-phase fluorescein angiograms showed multifocal leakage of the dye into the subretinal space. Electro-oculographic findings were abnormal only during the acute stage in the more severely affected eye and returned to normal within three months. The retinal detachment spontaneously resolved within three months; visual acuity returned to normal but some atrophic areas remained in the retinal pigment epithelium. Because the antibody titer to rubella was 1:1,028 during the acute stage but decreased to 1:257 within one month, we believe this patient had rubella retinitis, a rare condition in adults. The betamethasone may have made him more susceptible to the viral infection.

Retinal 's' antigen disease in rats

The form of experimental allergic uveoretinitis induced by sensitization with retinal 's' antigen in rats actually begins as a pars planitis and juxtapapillary choroiditis. Retinal inflammation develops at the middle limiting vascular layer of the retina and extends outward with focal destruction of photoreceptors and inward as a perivasculitis of small retinal vessels. Extensive choroiditis is a late development in severely diseased animals. Significant strain differences in susceptibility to disease were observed.

Antibody determination by ELISA in rats with retinal S antigen-induced uveoretinitis

Enzyme-linked immunosorbent assay was applied to the determination of the serum IgG antibody contents in rats immunized with the organ-specific autoantigen (S antigen) of the retina. Optimal conditions (i.e. S antigen concentration, serum and conjugate dilutions, enzymatic reaction time) were determined. The assay required only a single serum dilution and was well reproducible. It was very sensitive, allowing the detection of low antibody contents in animals immunized with 1 microgram of S antigen. The time course of the antibody response and its variations according to the dose and the species of the immunizing S antigen were considered.

Antibody to Toxocara canis in the aqueous humor

The aqueous humor and serum samples of patients with presumed ocular toxocariasis were examined by an enzyme-linked immunosorbent assay (ELISA) for antibody to the embryonated egg antigen. Using a single dilution (1:8), higher amounts of antibody have been found in the aqueous humor than in the serum samples. Antibody was not found in the serum or aqueous humor of patients with retinoblastoma, Coats' disease, uveal malignant melanoma, or central retinal artery obstruction. While two patients with presumed ocular toxocariasis had normal serum levels of antibody, the aqueous humor ELISA titers were greatly elevated, supporting the clinical diagnosis and suggesting localized antibody production.

Evidence for immediate hypersensitivity phenomena in experimental autoimmune uveoretinitis

Evidence is presented for the involvement of immediate hypersensitivity phenomena in experimental autoimmune uveoretinitis, an ocular inflammatory disease induced in Lewis rats by injection of the purified S antigen from bovine retina. Several parameters at various dates after immunization have been studied. In vivo degranulation of choroidal mast cells, in vitro degranulation of peritoneal mast cells in the presence of S antigen and cutaneous anaphylaxis were observed as early as 6-8 days after immunization. Serum antibodies were detected by passive hemagglutination from day 7 on. These phenomena preceded the onset of the ocular inflammation, consisting of a transient polymorphonuclear leukocyte infiltration, a long-lasting lymphoid cell infiltration and extensive damage to the retina and surrounding tissues. Such time course of events may suggest a role for reaginic antibody as a trigger for vascular changes in the target ocular tissue, favoring the development of inflammatory lesions.

S antigen-induced experimental autoimmune uveo-retinitis in rats

Experimental autoimmune uveoretinitis was induced in rats after one injection of purified retinal S antigen mixed with adjuvants. Lewis and PVG/c rat strains were highly sensitive. S antigens isolated from bovine, human, swine and guinea pig retinas had a high pathogenicity in Lewis rats, whereas allogenic S antigen did not induce the disease. Mycobacterial adjuvant was effect in both disease and antibody production but H. pertussis adjuvant strongly increased the severity of the ocular reaction, giving a hyperacute Arthus-type inflammation, even with low doses of antigen. No disease was found after immunization without bacteria (incomplete Freund's adjuvant or alum). With any bacterial adjuvant, the histological pattern was in agreement with the hypothesis of early reagin-mediated phenomena acting on the blood-retinal barrier, as suggested by previous experiments.

Cytomegalovirus retinitis in immunosuppressed hosts. I. Natural history and effects of treatment with adenine arabinoside

Cytomegalovirus (CMV) retinitis presents with typical ophthalmologic appearance in patients with underlying immunosuppressive conditions. Fourteen patients with this disorder were diagnosed by culture of cytomegalovirus from urine or throat specimens, elevated complement fixation titers to cytomegalovirus, and characteristic funduscopic appearance. Ten of 11 had decreased CMV-specific cell-mediated immune responses. Three of seven who received no specific therapy improved after decreasing dosages of immunosuppressive drugs. Seven patients with progressive disease despite minimal immunosuppressive therapy were treated with adenine arabinoside at doses from 1 to 20 mg/kg of body weight per day. Daily dosages of 20 mg/kg . d in five patients were associated with decreased inflammatory activity and improvement of retinal lesions and quantitative decreases in urinary virus excretion. Adenine arabinoside administration was associated with significant gastrointestinal, hematologic, and neurologic side effects. Adenine arabinoside may have some beneficial effect on selected patients with progressive CMV retinitis.

Cytomegalovirus retinitis in immunosuppressed hosts. II. Ocular manifestations

We observed the course of cytomegalovirus (CMV) retinitis in 21 eyes of 14 immunosuppressed patients. In two patients, other organisms, specifically Toxoplasma and Candida, also appeared to be causing retinal disease simultaneously. Post-mortem examination was done on 10 eyes from seven patients. At initial presentation, the retinitis was often asymptomatic and diagnosed during routine examination. The ophthalmoscopic picture was characteristic of cytomegalovirus; the early lesion was a small opaque, white granular area of retinal necrosis that spread in a centrifugal, brush-fire-like manner over 1 to 8 months. Vessel sheating and hemorrhages appeared as the disease progressed. In two patients new foci of retinitis developed remote from the original lesion. Four weeks to 4 months (average, 10 weeks) elapsed from the most extensive disease to total resolution. Resolution of active disease left a subtle retinal scar, and final visual acuity was reduced in one half the eyes. Repeated ophthalmoscopic examinations can aid in early diagnosis of CMV retinitis and in ascertaining which persons are most at risk for visual loss.

[Protein concentrations in the aqueous humor in Coats' disease (author's transl)]

Elevated protein concentrations in the aqueous humor, without Tyndall phenomenon, were found in a case of Coats' Disease. In particular, proteins of smaller size were involved. The permeability of the retinal vessels was presumed to be impaired. The resulting increase in protein concentrations in the aqueous humor could be the cause of the secondary glaucoma in Coats' Disease.

Hyperacute form of experimental autoimmune uveo-retinitis in Lewis rats; electron microscopic study

One systemic injection of retinal tissue or extract mixed with Freund's complete adjuvant induces uveo-retinitis in several animal species: guinea pig [6], rabbit [5, 7], monkey [4] and rat [8]. Rod outer segments may be used as the pathogenic antigenic preparation [1, 3, 9]. This study reports on the conditions of induction of experimental autoimmune uveo-retinitis (EAU) in rats (susceptible strains of rats, optimal doses of antigen and adjuvant) and the histopathological features of the lesions in the early stages of the disease. In several species one systemic injection of retinal tissue or extract mixed with Freund's complete adjuvant induces an ocular inflammatory disease, whose main features are an inflammatory infiltration of the uvea and a destruction of the external layers of the retina. With adequate doses of guinea pig retinal extract and adjuvant, the disease was induced in all cases in albino rats of the Lewis strain. The vascular and tissular lesions, and the infiltrates with a predominance of PMN's and basophils seem to be the result of immune complexe deposition.

Necrotizing vaso-occlusive retinitis

We studied two adult patients with fulminating, necrotizing vaso-occlusive retinitis, and documented the progressive course of retinal necrosis, vitreoretinal interface contraction, and consequent retinal detachment. The systemic criteria for Behçet's disease were present in one patient, and partially fulfilled in the second.

[Experimental autoimmune uveo-retinitis (EAU): cellular immunity and humoral antibodies in the induction of ocular lesions and tolerance to retinal antigens]

EAU is induced in guinea pigs by one inoculation into the foot-pad of a retinal extract in complete Freund's adjuvant. The evolution of the antibodies (complement fixation) is compared with the évolution of the disease (intensity evaluated by frequent ophthalmological examinations). The successful passive transfer of the disease by local injections of immune serum and the demonstration by immunofluorescence of immune complexes in the ocular tissues are arguments for the role of humoral antibodies in the induction of the disease. EAUmay be inhibited by repeated subcutaneous or intradermal injections of the antigen, either before or after the onset of the inflammation. These injections depress the delayed hypersensitivity and increase the titre of complement fixing and passive anaphylactic antibodies.

[Isolation and characterization of a retinal antigen inducing experimental autoimmune uveo-retinitis]

A soluble antigen was extracted from the retinas of different mammals and purified by isoelectric focusing in a sucrose density gradient-ampholine column (LKB, Sweden). The isoelectic point of the molecule is about 5.5, its molecular weight about 55,000 and its electrophoretic mobility with reference to albumin 0.7. The S antigen is revealed by one precipitin line in immunodiffusion and immunoelectrophoresis with guinea pig immune sera against bovine or guinea pig retinas, and shows an identity reaction with S antigen from other species. The antigen, inoculated with complete Freund's adjuvant into the guinea pig foot pad, induces experimental uveo-retinitis.

[Experimental autoimmune uveoretinitis. Ultrastructure of chorioretinal lesions induced in guinea pigs by immunization against the outer rods of the bovine retina]

The uveoretinitis induced in guinea pigs by one systemic injection of rod outer segments from bovine retina has the following ultrastructural features : 1 to 3 weeks after the injection, first early alterations of the visual cells and pigment epithelium, phagocytosis of fragmented outer segments by macrophages, development of an inflammatory infiltrate of the uvea with numerous plasma cells. During the second month, polymorphic inflammatory reaction in the choroid, destruction of photoreceptors in large areas with preservation of the external limiting membrane or involvement of the internal layers of the retina. During the next months, fibroblastic healing processes, but persistence of a diffuse inflammation, with sub-retinal lymphoid follicles and epithelioid cells. It appears likely that pigment epithelium and outer segments of the visual cells are targets for the initial immunological attack, where humoral antibodies seem to play a major role.

Homologous retinal outer segment immunization in primates. A clinical and histopathological study

Immune intraocular inflammation was induced in primates with homologous retinal outer segments. Perivascular retinitis, uveitis, and edema of the optic nerve head were the prominent acute clinical features. Acute and chronic inflammation was seen in the central and peripheral retinal vessels and granulomatous infiltration was present in the choroid of the uvea. Selective degeneration of the outer segments of the photoreceptor cells of the retina with sparing of the inner segments and of the adjacent pigment epithelium was confirmed by light and electron microscopy. This study strongly suggests that photoreceptor outer segments are highly and specifically immunogenic. The inciting antigen has yet to be identified. Implication of rhodopsin will have to await further studies since it exists as the essential protein in the outer segment.