Reacción en cadena de la polimerasa en fluidos oculares en las formas atípicas de uveítis posterior / Polymerase chain reaction in ocular fluids in atypical forms of posterior uveitis

RESUMEN La toxoplasmosis ocular es la causa de uveítis posterior más frecuente en muchos países. El diagnóstico correcto se basa principalmente en las características clínicas de la enfermedad; pero en las formas de uveítis posterior atípicas se necesita el apoyo del laboratorio para confirmar el diagnóstico y no indicar tratamientos inapropiados. Se resalta el valor de la reacción en cadena de la polimerasa en fluidos oculares en pacientes con títulos serológicos en suero positivos para toxoplasma y presentaciones atípicas de uveítis posterior. Se presenta un caso clínico de una paciente con toxoplasmosis sistémica, confirmada con títulos serológicos en suero positivos, quien concomitó con uveítis posterior bilateral sin características típicas de toxoplasmosis ocular, en la cual la reacción en cadena de la polimerasa de fluidos oculares fue esencial en el diagnóstico. La reacción en cadena de la polimerasa en fluidos oculares constituye una herramienta inequívoca en el diagnóstico correcto de las formas atípicas de uveítis posteriores(AU)

ABSTRACT Ocular toxoplasmosis is the most frequent cause of posterior uveitis in many countries. Correct diagnosis is mainly based on the clinical characteristics of the disease, but in atypical forms of posterior uveitis laboratory support is required to confirm the diagnosis and not indicate inappropriate treatments. Evidence is provided of the usefulness of polymerase chain reaction in ocular fluids from patients with serum serological titers positive for toxoplasma and atypical presentations of posterior uveitis. A clinical case is presented of a female patient with systemic toxoplasmosis confirmed by positive serum serological titers and concomitant bilateral posterior uveitis without typical features of ocular toxoplasmosis, in which polymerase chain reaction in ocular fluids was essential for the diagnosis. Polymerase chain reaction in ocular fluids is an unequivocal tool for the correct diagnosis of atypical forms of posterior uveitis(AU)

Risk of reactivation of toxoplasmic retinitis following intraocular procedures without the use of prophylactic therapy.

BACKGROUND/AIMS: Toxoplasmic retinochoroiditis is the commonest known cause of posterior uveitis worldwide and reactivation is unpredictable. Based on results from one study, the authors proposed that antitoxoplasmic therapy should be initiated as prophylaxis for intraocular surgery in patients with toxoplasmic scars. The aim of this study is to analyse the risk of toxoplasmic retinochoroiditis reactivation following intraocular procedures. METHODS: Retrospective analysis of the medical records of a total of 69 patients who underwent intraocular surgery and presented with toxoplasmic retinochoroiditis scars. RESULTS: No patient received prophylactic antitoxoplasmic therapy. Reactivation following the surgical procedure occurred in four cases, with one at 3 months and the others respectively at 13, 14 and 17 months. CONCLUSIONS: Our study shows that intraocular surgery did not result in a significant reactivation rate of toxoplasmic retinochoroiditis in the absence of preoperative prophylactic antitoxoplasmic therapy.

Retinocoroidite toxoplásmica reativada provavelmente por cirurgia refrativa: laser in situ keratomileusis - LASIK / Probable reactivation of toxoplasmic retinochoroiditis by refractive surgery: laser in situ keratomileusis - LASIK

O presente trabalho objetiva demonstrar provável relaço entre recorrência de toxoplasmose ocular e cirurgia refrativa (LASIK). Trata-se de relato de caso de um paciente de 33 anos de idade com recorrência de retinocoroidite toxoplásmica após cirurgia de LASIK. O exame fundoscópico do olho esquerdo revelou foco de retinocoroidite em atividade, satélite a cicatriz antiga de toxoplasmose ocular, 17 dias após cirurgia de LASIK. Os autores apresentam subsídios para o estabelecimento de relação causal entre LASIK e a reativação de retinocoroidite toxoplasmática.

The aim of this article is to demonstrate the probable relationship between the recurrence of toxoplasmic retinochoroiditis and refractive surgery (LASIK). The case consists in a toxoplasmic retinochoroditis recurrence observed in a 33-year-old patient after a LASIK surgery. Fundoscopy revealed a retinochoroiditis focus in activity in the left eye seventeen days after the surgery, adjacent to an old scar of ocular toxoplasmosis. The authors present findings that reinforce possible causal links between LASIK and the recurrence of toxoplasmic retinochoroiditis.

Avaliação oftalmológica em pacientes com AIDS e neurotoxoplasmose / Ophthalmological evaluation of patients with AIDS and neurotoxoplasmosis

INTRODUÇÃO: Descrever os achados fundoscópicos em pacientes com AIDS e neurotoxoplasmose em fase ativa. MÉTODOS: Foi desenvolvido estudo prospectivo tipo série de casos incluindo 70 pacientes, de ambos os sexos, com idade variando de 20 a 63 anos, internados nas enfermarias de três hospitais públicos da Cidade do Recife, Pernambuco, com diagnósticos de AIDS e neurotoxoplasmose firmados segundo os critérios do Centers for Disease Control and Prevention (1992), no período de janeiro a outubro de 2008. Os pacientes se caracterizavam por: primeiro episódio de neurotoxoplasmose (65; 92,9 por cento) ou recidiva (5; 7,1 por cento); desconhecimento de ter AIDS (23; 32,9 por cento), contagem média de linfócitos T CD4 de 139,8 ± 3,04 células/mm3 e carga viral média igual a 137.080 ± 39.380 cópias/mL. Todos foram submetidos a exame oftalmológico, consistindo de: inspeção ocular; aferição da acuidade visual; investigação da função muscular extrínseca ocular e fundoscopia, empregando oftalmoscópio indireto binocular (modelo OHN 3.5 (Eyetec®) e lente externa de 20 dioptrias (Volk®). RESULTADOS: Os achados consistiram em: exsudatos algodonosos retinianos (8,6 por cento), constricção arteriolar difusa leve (8,6 por cento); lesões de retinocoroidite cicatricial, características de toxoplasmose ocular (5,7 por cento), atrofia do epitélio pigmentar retiniano (2,9 por cento), descolamento da retina (2,9 por cento), aumento de escavação papilar (1,4 por cento), degeneração periférica retiniana (1,4 por cento), macroaneurisma (1,4 por cento), papiledema bilateral (1,4 por cento), tração vítreo-retiniana (1,4 por cento). CONCLUSÕES: Pacientes com AIDS e neurotoxoplasmose podem apresentar alterações fundoscópicas características da toxoplasmose ocular, na forma ativa ou cicatricial, relacionadas ao HIV ou, ainda, a outras doenças oportunistas ou sistêmicas, podendo ser de grande auxílio num tratamento integral do paciente por uma equipe multiprofissional.

INTRODUCTION: To describe fundoscopic findings among patients with AIDS and active-phase neurotoxoplasmosis. METHODS: A prospective study of case series type was developed, including 70 patients of both sexes and ages ranging from 20 to 63 years who were admitted to the wards of three public hospitals in the city of Recife, Pernambuco, Brazil, from January to October 2008, with diagnoses of AIDS and neurotoxoplasmosis determined according to the criteria of the Centers for Disease Control and Prevention (1992). The patients were characterized by a first episode of neurotoxoplasmosis (65; 92.9 percent) or recurrence (5; 7.1 percent), unawareness of having AIDS (23; 32.9 percent), mean T CD4+ count of 139.8 ± 3.04 lymphocytes/mm³ and mean viral load of 137,080 ± 39,380 copies/ml. All patients underwent ophthalmological examination consisting of ocular inspection, gauging of visual acuity, investigation of ocular extrinsic muscle function and fundoscopy using a binocular indirect ophthalmoscope (model OHM 3.5 Eyetec®) and external lens of 20 diopters (Volk®). RESULTS: The findings consisted of retinal cotton-wool spot exudates (8.6 percent), slight diffuse arteriolar constriction (8.6 percent), retinochoroiditis scars characteristic of ocular toxoplasmosis (5.7 percent), atrophy of retinal pigment epithelium (2.9 percent), retinal detachment (2.9 percent), increased papillary excavation (1.4 percent), retinal peripheral degeneration (1,4 percent), macroaneurysm (1.4 percent), bilateral papilledema (1.4 percent) and vitreous-retinal traction (1.4 percent). CONCLUSIONS: Patients with AIDS and neurotoxoplasmosis may present fundoscopic abnormalities characteristic of ocular toxoplasmosis, either in active or in scar form, related to HIV or even to other opportunist or systemic diseases, which can be of great aid for integral treatment of patients by a multiprofessional team.

Increased frequency of anti-retina antibodies in asymptomatic patients with chronic t. gondii infection

PURPOSE: To search for anti-retina antibodies that serve as markers for eye disease in uveitis. MATERIALS AND METHODS: Stored sera from patients with uveitis, ocular toxoplasmosis (n = 30) and non-infectious, immune-mediated uveitis (n = 50) and from asymptomatic individuals who were positive (n = 250) and negative (n = 250) for anti-Toxoplasma antibodies were tested. Serum anti-retina IgG was detected by an optimized ELISA using a solid-phase whole human retina extract, bovine S-antigen or interphotoreceptor retinoid-binding protein. RESULTS: Uveitis patients showed a higher mean reactivity to whole human retina extract, interphotoreceptor retinoid-binding protein and S-antigen in comparison to the asymptomatic population. These findings were independent of the uveitis origin and allowed the determination of the lower anti-retina antibody cut-off for the three antigens. Asymptomatic anti-Toxoplasma serum-positive individuals showed a higher frequency of antihuman whole retina extract antibodies in comparison to asymptomatic anti-Toxoplasma serum-negative patients. The bovine S-antigen and interphotoreceptor retinoid-binding protein ELISAs also showed a higher mean reactivity in the uveitis groups compared to the asymptomatic group, but the observed reactivities were lower and overlapped without discrimination. CONCLUSION: We detected higher levels of anti-retina antibodies in uveitis patients and in a small fraction of asymptomatic patients with chronic toxoplasmosis. The presence of anti-retina antibodies in sera might be a marker of eye disease in asymptomatic patients, especially when whole human retina extract is used in a solid-phase ELISA.

Reactivation of ocular toxoplasmosis after LASIK.

PURPOSE: To report a reactivation of ocular toxoplasmosis after LASIK. METHODS: Case report of a 34-year-old man who underwent bilateral LASIK. The posterior segment examination revealed an old toxoplasmosis scar in the retinal periphery of the right eye. RESULTS: Uncorrected visual acuity improved postoperatively, and the patient was satisfied. However, 52 days after the procedure, he complained of loss of visual acuity in his right eye. Examination revealed signs of anterior uveitis, vitreitis, and active chorioretinal lesion satellite of the old toxoplasmosis scar. The patient was treated with a multidrug regiment with resolution of the vitreous and lesion activity. CONCLUSIONS: Toxoplasmosis reactivation may develop after LASIK.

Involvement of apoptosis and interferon-gamma in murine toxoplasmosis.

PURPOSE: A murine toxoplasmosis model has been developed that results in central nervous system (CNS) and ocular inflammation characterized by encephalitis with numerous brain tissue cysts and milder inflammation with rare tissue cysts in the eye after 4 weeks of Toxoplasma gondii infection. In this model IFN gamma and inducible nitric oxide (iNO) are protective against T. gondii infection. In this study, the role of apoptosis in the pathogenesis of toxoplasmosis was investigated. METHODS: C57BL/6 (wild-type mice), B6MRL/lpr, and B6MRL/gld (defective Fas or FasL expression, respectively) mice were infected intraperitoneally with 20 to 30 tissue cysts of the ME-49 strain of T. gondii. Mice were killed at days 0, 14, or 28 after infection. The eyes and brains were harvested for histologic, immunohistochemical, and molecular studies. Analysis included immunostaining for Fas, FasL, Bcl-2, and Bax; in situ apoptosis detection (TUNEL assay); RT-PCR amplification for IFN gamma; and measurement of ocular nitrite levels. The control mice were naïve mice of each strain that received no inoculation or injection. RESULTS: Wild-type mice appeared to constitutively express apoptotic molecules at higher levels in the eye than in the brain. Consequently, during T. gondii infection, apoptosis was greater in the eyes than in the brain. Untreated naïve lpr and gld mice showed no expression of Fas and FasL, respectively. After infection, a slightly higher number of tissue cysts (lpr, 11.8 +/- 2.4; gld, 10.3 +/- 3.4) were found in the brains of the mutants than in the control animals (8.8 +/- 2.9). However, no significant differences between the number of apoptotic cells, inflammatory scores, or number of tissue cysts were noted in the eyes. IFN gamma mRNA in control mice was detected at day 28 after infection, whereas in both mutants, mRNA production occurred earlier, at day 14. Ocular nitrite levels were higher in lpr and gld mice than in wild-type mice. CONCLUSIONS: No significant difference in the degree of ocular inflammation and apoptosis was detected between the wild-type and Fas or FasL mutant mice. However, there was an earlier and subjectively greater expression of IFN gamma in the brain and eye and a higher level of nitrite in the ocular tissue of mutant strains than in the wild type. Multiple factors are likely to be involved in the pathogenesis of ocular toxoplasmosis.

[New trends in ocular toxoplasmosis--the review]. / Wspólczesne poglady na toksoplazmoze narzadu wzroku.

For past ten years some new trends can be observed in the field of ocular toxoplasmosis. In this article on the basis of reviewing scientific articles the author tried to point out important, or new information which may have an impact on clinical researches and clinical practice in the close future. 1. There is evidence that some tissue cysts can be present in untouched retinal tissue, and can produce an inflammatory reaction even many years after primary infection. This concerns both congenital and acquired toxoplasmosis. 2. The coexistence of intraocular inflammatory reaction without focal necrotizing retinochoroiditis in patients with acquired systemic toxoplasmosis was described--but there is no evidence that those inflammations were directly cause by T. gondii parasite themselves. It is too early to include this changes into the classical clinical picture of toxoplasmic retinochoroiditis. 3. For the past ten years there have been published articles showing higher prevalence of acquired ocular toxoplasmosis but this is well documented only in south America. In Europe and USA the frequency of ocular toxoplasmosis cases are low. Despite the different percentage of infected people in these populations, this controversial result can be caused by different distribution of pathogenic and non-pathogenic strains of the parasite as like by differences in human genotypes. 4. There is model of "dynamic equilibrium" existing between host defence and parasite cyst ruptures helpful for understanding reactivation. Level of tissue cyst-specific antigens does not rise in the population of HIV patients or during reactivation of ocular retinochoroiditis--this places the responsibility for reactivation on the side of host immunoresponse. 5. The most specific and reliable laboratory assessment for ocular toxoplasmosis, which is specifically helpful in clinically atypical cases, is combination of IgG, IgA and IgM serology tests made of serum and intraocular fluids. It can proof intraocular production of antibodies. PCR tests have got some value, but they are not as efficient as have been thought previously. 6. There is no efficient treatment diminishing recurrence rate and the time of singular inflammation yet. The combination of pyrimethamine, sulfadiazine and clindamycin, given for 3 to 4 weeks with supplementation of folinic acid for diminishing side effects, can diminish the measure of future scar. Long lasting treatment as it is used in children with congenital disease or in HIV patients can be probably more efficient. Atovaquone is as effective as traditional drugs and gives fewer side effects.

Acquired and congenital ocular toxoplasmosis experimentally induced in Calomys callosus (Rodentia, Cricetidae).

An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimmune uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant- and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40% of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75% of the females and 50% of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as additional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitute in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection.

Fas-FasL interaction involved in pathogenesis of ocular toxoplasmosis in mice.

Ocular toxoplasmosis is a potentially blinding intraocular inflammation. The intent of this study was to investigate the role of Fas-FasL interaction in a murine model of acquired ocular toxoplasmosis induced by intracameral inoculation of Toxoplasma gondii. Intraocular inflammation, Fas and FasL expression on lymphocytes and on ocular tissues, the occurrence of apoptosis, and the frequency of CD8(+) and CD4(+) T cells in the infected eyes were analyzed in C57BL/6 (B6) mice. Susceptibility to parasite-induced intraocular inflammation was observed in Fas-deficient (B6-lpr) and FasL-deficient (B6-gld) mice. Inoculation of 5,000 T. gondii tachyzoites induced significant intraocular inflammation associated with increase of Fas and FasL expression in the inoculated eyes of wild-type B6 mice. Flow cytometry demonstrated a significant increase of Fas and FasL expression on the splenocytes from naive mice incubated in vitro with the parasite and on the splenocytes harvested from the infected mice at day 8 after parasite inoculation. Apoptosis of inflammatory cells and cells in ocular tissues was seen, and a greater frequency of CD8(+) than CD4(+) T cells was observed in the infected eyes. The intensity of intraocular inflammation was greater in B6-lpr and B6-gld mice than in wild-type B6 mice (P < 0.05). The results suggest that Fas-FasL interaction associated with apoptosis is involved in the pathogenesis of acquired ocular toxoplasmosis in mice.

Toxoplasma retinitis/encephalitis 9 months after allogeneic bone marrow transplantation.

In a 34-year-old patient toxoplasma retinitis/encephalitis developed 9 months after bone marrow transplantation. The BMT was complicated with a serious GVHD. Although she initially responded well to antibiotic therapy she died 2 years after BMT due to progressive infection.

Retinal findings and characteristics in AIDS patients with systemic Mycobacterium avium-intracellulare complex and toxoplasmic encephalitis.

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate the incidence and characteristics of retinal and choroidal manifestations of toxoplasmosis and/or Mycobacterium avium-intracellulare complex (MAC) in patients with acquired immunodeficiency syndrome (AIDS). PATIENTS AND METHODS: The authors analyzed their prospectively collected data and found 120 patients with new retinal lesions (group A) that were diagnosed 3 months or longer following the diagnosis of MAC and/or toxoplasmic encephalitis. The authors also performed a point prevalence study of retinal/choroidal findings in 25 consecutive AIDS patients (group B) without known eye disease who had been recently treated for toxoplasmic encephalitis and/or disseminated MAC infections. In addition, the characteristics of retinochoroidal toxoplasmosis scars in 5 AIDS patients were studied and compared with the characteristics of scars in 18 immunocompetent patients. RESULTS: In this study the incidence of ocular manifestations of MAC was zero (95% confidence interval [CI] 0.0% to 3.8%). Two of 25 patients (8%) (95% CI 1% to 26%) in group A and 2 of 11 patients (18.1%) (95% CI 3.3% to 51.8%) in group B had toxoplasmic retinochoroiditis. CONCLUSION: In AIDS patients, ocular manifestations of toxoplasmosis are more common than ocular MAC. In addition, when compared with immunocompetent patients, AIDS patients tend to have retinochoroidal scars with less retinal pigment epithelium hyperplasia (1.8+ vs 3+) (P = .03).

The evolution of ocular toxoplasmosis in anti-interferon gamma treated mice.

PURPOSE: A clinico-histopathological cross correlation was made to study the mechanism of tissue damage in toxoplasmic retino-choroiditis during an experimental reactivation of chronic toxoplasmosis and to compare the influence of treatment by sulfadiazine on the retinal lesions. METHODS: Chronically infected Swiss-Webster mice were treated, six weeks after infection, with an avirulent strain of Toxoplasma gondii (Beverley strain) with polyclonal rabbit antibody directed against murine interferon gamma. RESULTS: Mice treated by anti-interferon gamma developed clinical lesions between day 5 and day 30 (lesions including single foci of retinochoroiditis, multifocal lesions or diffuse areas of retinal necrosis). These lesions did not arise from borders of pre-existing scars. The retina was photographed with an operating microscope fitted with a 90 diopter lens. Biological study showed a significant rise of parasitic loads in the eye and brain. Histological examination is in favour of free organism dissemination via retinal vessels; the lesions are restricted to the inner retina and ciliary body, the parasites migrated from extra-ocular cysts via the vasculature. No cysts were seen at the beginning of the study; they were found at the scar phase and appeared in mice treated with sulfadiazine. The clinical lesions were not caused by cysts but by coagulated necrosis in the retinal tissue. Parasite migration may have played a trigger role. CONCLUSIONS: The retinal damage was constituted either as a result of a toxic effect of the organisms or as a hypertensive reaction to the toxoplasma organism. The results of this study showed that the treatment with anti interferon gamma was sufficient to reactivate chronic infection.