Potencial do teste IGRA (Interferon Gama Release Assay) para o diagnóstico de tuberculose ocular. Revisão e análise comparativa com o teste tuberculínico cutâneo (PPD) / The potential of the IGRA (Interferon Gamma Release Assay) test for the diagnosis of ocular tuberculosis. Review and comparative analysis with the tuberculosis skin test

Resumo A detecção precisa da infecção latente por tuberculose está se tornando cada vez mais importante devido ao aumento do uso de medicamentos imunossupressores e da epidemia do vírus da imunodeficiência humana, o que aumentou o risco de reativação à tuberculose ativa (TB). O Teste IGRA QuantiFERON® TB Gold apresenta vantagens frente ao teste de PPD como por exemplo, requer somente uma coleta de amostra sanguínea ; não há necessidade que o paciente retorne ao laboratório para leitura e interpretação dos resultados; Os resultados são objetivos, não requerem interpretação do leitor ou interferência de critérios subjetivos; trata-se de um teste in vitro, portanto não há "efeito booster" (potenciação da reação tuberculínica); o teste não é afetado por vacinação prévia por BCG ou infecção por outras espécies de micobactérias. Limitações são descritas, apesar de raras, como reações cruzadas deste método com infecções por algumas espécies de micobactérias não-tuberculosis (incluindo Mycobacterium kansasii, Mycobacterium szulgai e Mycobacterium marinum). Ainda há poucos dados sobre o teste IGRA em certas populações, como por exemplo, em crianças, pacientes imunocomprometidos e mulheres grávidas. Nestes grupos, a interpretação do teste pode ser difícil e mais estudos se fazem necessários.

Abstract Precise detection of latent tuberculosis infection is becoming increasingly important due to increased use of immunosuppressive drugs and the human immunodeficiency virus epidemic , which increased the risk of reactivation to active tuberculosis (TB).The QuantiFERON® TB Gold IGRA Test has advantages over the skin test for TB, otherwise known as a Mantoux tuberculin test, for example, requires only a blood sample collection; there is no need for the patient to return to the laboratory for reading and interpretation of the results; The results are objective, do not require interpretation of the reader or interference of subjective criteria; it is an in vitro test, so there is no "booster effect" (potentiation of the tuberculin reaction); the test is not affected by prior BCG vaccination or infection with other species of mycobacteria. Limitations are described, although rare, as cross-reactions of this method with infections by some species of non-tuberculosis mycobacteria (including Mycobacterium kansasii, Mycobacterium szulgai and Mycobacterium marinum). There is still little data on the IGRA test in certain populations, such as in children, immunocompromised patients and pregnant women. In these groups, the interpretation of the test can be difficult and more studies are needed.

Serum levels of neurotrophic factors in active toxoplasmic retinochoroiditis

Abstract Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. Methods: Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. Results: BDNF levels were significantly higher in patients before treatment when compared with controls (p = 0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. Conclusion: BDNF may be released in the context of the active TR inflammatory response.

T cell immunoregulation in active ocular toxoplasmosis.

Toxoplasma gondii infection is an important cause of infectious ocular disease. The physiopathology of retinochoroidal lesions associated with this infection is not completely understood. The present study was undertaken to investigate cytokine production by T cells from individuals with active toxoplasmic retinochoroiditis (TR) comparing with controls. Eighteen patients with active TR and 15 healthy controls (6 controls IgG+ to Toxoplasma and 9 negative controls) were included in the study. Peripheral blood mononuclear cells were incubated in the presence or absence of T. gondii antigen (STAg), and stained against CD4, CD8, TNF, IL-10 and IFN-γ. Baseline expression of cytokines was higher in TR/IgG+ patients in comparison with controls. Cytokine expression was not increased by STAg in vitro stimulation in controls. After stimulation, TR/IgG+ patients' lymphocytes increased cytokine as compared to cultures from both controls. While T cells were the main source of IL-10, but also IFN-γ and TNF, other lymphocyte populations were relevant source of inflammatory cytokines. Interestingly, it was observed a negative correlation between ocular lesion size and IL-10 expression by CD4+ lymphocytes. This study showed that T cells are the main lymphocyte populations expressing IL-10 in patients with TR. Moreover, expression of IL-10 plays a protective role in active TR.

Serum levels of neurotrophic factors in active toxoplasmic retinochoroiditis.

Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. METHODS: Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. RESULTS: BDNF levels were significantly higher in patients before treatment when compared with controls (p=0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. CONCLUSION: BDNF may be released in the context of the active TR inflammatory response.

New drug delivery system for corneal administration of mitomycin-C.

PURPOSE: To develop a new corneal release system to deliver optimum amounts of mitomycin-C (MMC) during the perioperative period of photorefractive keratectomy (PRK). SETTING: Ophthalmos S/A, São Paulo, Brazil. DESIGN: Experimental study. METHODS: An in vitro experimental design was developed for studying a new MMC delivery system at a drug concentration of 0.02%. Whatman sterile filter paper disks with a diameter of 8.0 mm were impregnated with MMC solution. After drying, the disks were placed on agar plates seeded with Staphylococcus epidermidis; this was followed by instillation of a drop of sterile water. After 1 minute, the disks were removed and the plates were incubated for 48 hours at 35°C. The mean volume of the drops delivered from regular eyedrop bottles was determined, and the inhibition zone (in millimeters) was correlated with the amount of MMC loaded onto the disks. RESULTS: Analysis of the inhibition zones produced by MMC indicated that 16 µg was the optimum dose to be incorporated in the disks. The mean volume of a drop delivered from eyedrop bottles was 37.7 µL. One minute after the application of a single drop of a balanced salt solution, the system released an adequate concentration of MMC for PRK. CONCLUSION: A new delivery system for MMC was successfully developed for application during photorefractive keratectomy. FINANCIAL DISCLOSURE: Dr. de Souza Lima Filho is the managing director of Ophtalmos S/A. Drs. de Souza Lima Filho, Irochima Pinheiro, and Oréfice have exclusive rights to intellectual property of this invention secured by a patent application filed with the Instituto Nacional da Propriedade Industrial.

Multimodal Imaging Assisting the Early Diagnosis of Cat-Scratch Neuroretinitis.

To describe how a multifocal fundus imaging system assisted the early diagnosis of cat scratch neuroretinitis in a case of a 27-year-old male with unilateral visual loss, neuroretinitis, and a peripapillary angiomatous lesion. Multimodal fundus imaging analysis was an essential contributor to the clinical diagnosis of cat scratch neuroretinitis during the early stage of the disease.

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.

Morphometric changes in C57BL/6 mice retina infected by Toxoplasma gondii ME 49 strain.

This study evaluated the morphometric implications in C57BL/6 mouse retina infected by Toxoplasma gondii, ME 49 strain. Twenty C57BL/6 female mice were divided into group 1 (n=8, intraperitoneally infected with 30 cysts of T. gondii ME 49 strain) and group 2 (n=12 non-infected controls). The eyes were enucleated on the 60th day after infection, fixed and processed for light microscopy. Changes in retinal thickness and in the perimeter/area ratio (P/A) of the retinal layers were analyzed by digital morphometry. We considered that P/A was the measurement of retinal architecture distortion induced by toxoplasmosis. This study considered the ganglion cells and nerve fiber layers as a monolayer, thus six layers of retina were evaluated: photoreceptors (PRL), outer nuclear (ONL), outer plexiform (OPL), inner nuclear (INL), inner plexiform (IPL) and ganglion cells/nerve fiber monolayer (GNL). Histological analysis of infected mouse retina showed inflammatory infiltrate, necrosis, glial reaction and distortion of the retina architecture. It also presented increased thickness (167.8±24.9µm versus 121.1±15.4µm, in controls) and increased retinal thickness within the retinitis foci (187.7±16.6µm versus 147.9±12.2µm out of the retinitis foci). A statistically significant difference in P/A was observed between infected and uninfected mouse retinas. The same was observed in PRL, OPL, INL and GNL. Retinal morphometry may be used to demonstrate differences between infected and uninfected mouse retinas.

Interleukin-6 gene polymorphism (-174 G/C) is associated with toxoplasmic retinochoroiditis.

PURPOSE: Experimental data have demonstrated a relevant role for IL-6 in the modulation of acute ocular toxoplasmosis. Therefore, we aim to investigate the possible association between the IL-6 gene polymorphism at position -174 and toxoplasmic retinochoroiditis (TR) in humans. METHODS: Ninety-seven patients with diagnosed TR were recruited from the Uveitis Section, Federal University of Minas Gerais. For comparison, 83 healthy blood donors with positive serology for toxoplasmosis and without retinal signs of previous TR were included in the study. Genomic DNA was obtained from oral swabs of individuals and amplified using polymerase chain reaction (PCR) with specific primers flanking the locus -174 of IL-6 (-174G/C). PCR products were submitted to restriction endonuclease digestion and analysed by polyacrylamide gel electrophoresis to distinguish allele G and C of the IL-6 gene, allowing the detection of the polymorphism and determination of genotypes. RESULTS: There was a significant difference in the genotype (χ(2) = 12.9, p = 0.001) and allele (χ(2) = 6.62, p = 0.01) distribution between TR patients and control subjects. In a subgroup analysis, there was no significant difference in genotypes and allele frequencies regarding TR recurrence. CONCLUSIONS: This study suggests that the genotypes related with a lower production of IL-6 may be associated with the occurrence of TR.

Spectral optical coherence tomography findings in patients with ocular toxoplasmosis and active satellite lesions (MINAS Report 1).

PURPOSE: To characterize the active retinochoroiditis lesion observed in patients with the classic clinical presentation of ocular toxoplasmosis (OT) utilizing spectral optical coherence tomography (SOCT). METHODS: Twenty-four patients with OT and satellite lesions underwent standardized ophthalmologic examination and multimodal fundus imaging. The SOCT findings observed at presentation were described. RESULTS: The mean age of the fourteen (58.3%) women and ten (41.7%) men was 27.6 years. The mean LogMAR ETDRS best-corrected visual acuity was 0.58 (Snellen equivalent, 20/80(+1) ). On SOCT evaluation, the posterior hyaloid was diffusely thickened in 23 (95.8%) of 24 eyes, increased hyper-reflective signals in the vitreous were observed in 18 (75.0%), and vitreal spherical hyper-reflective depositions were observed in 12 (50.0%) eyes. In all patients, at the active OT lesion site, the inner retinal layers were abnormally hyper-reflective with full-thickness disorganization of the retinal reflective layers (smudge effect); associated choriocapillaris/choroidal optical shadowing was observed in 22 (91.7%) eyes. The retina was thickened in 22 (91.7%) eyes, the retinal pigment epithelium-Bruch membrane reflective complex was focally increased or contained focal splits in 16 (66.7%) eyes and the choroid appeared thickened in 17 (70.8%) eyes. Disorganization of the outer retinal highly reflective layers adjacent to the active OT lesion was observed in all eyes. CONCLUSION: Full-thickness disorganization of the retinal reflective layers, generally associated with some degree of posterior optical shadowing, was observed in the active OT lesion in all patients. The posterior hyaloid was often thickened and, adjacent to the OT lesion, the outer retina was consistently altered.

Increased serum levels of soluble tumor necrosis factor receptor-2 (sTNFR2) in patients with active toxoplasmic retinochoroiditis

This study aimed to investigate the serum levels of the cytokine TNF-α and its soluble receptors (sTNFR1 and sTNFR2) in patients with toxoplasmosis retinochoroidits (TR) and controls. 37 patients with TR and 30 subjects with positive serology for toxoplasmosis but without history and signs of uveitis were included in this study. Serum concentrations of TNF-α, sTNFR1, and sTNFR2 were determined by ELISA. Serum concentrations of TNF-α and sTNFR1 were similar in controls (mean ± SD median values; 56.57 ± 141.96 and 504.37 ± 163.87, respectively) and TR patients (mean ± SD values, 121.62 ± 217.56 and 511.15 ± 189.30, respectively). Serum concentrations of sTNFR2 were higher in the uveitis group when compared to the control group (respectively, mean ± SD values, 1734.84 ± 379.32 and 1442.75 ± 309.47; p=0.002). There was no association between the serum levels of the molecules and the time of first symptoms, severity of vitreous haze, size or localization of active lesions, levels of visual acuity, and presence of vasculitis. These results suggest that TR is associated with changes in the circulating levels of inflammatory biomarkers, but they are not correlated with local/ocular signs.

Increased serum levels of soluble tumor necrosis factor receptor-2 (sTNFR2) in patients with active toxoplasmic retinochoroiditis.

This study aimed to investigate the serum levels of the cytokine TNF-α and its soluble receptors (sTNFR1 and sTNFR2) in patients with toxoplasmosis retinochoroiditis (TR) and controls. 37 patients with TR and 30 subjects with positive serology for toxoplasmosis but without history and signs of uveitis were included in this study. Serum concentrations of TNF-α, sTNFR1, and sTNFR2 were determined by ELISA. Serum concentrations of TNF-α and sTNFR1 were similar in controls (mean ± SD median values; 56.57±141.96 and 504.37±163.87, respectively) and TR patients (mean ± SD values, 121.62±217.56 and 511.15±189.30, respectively). Serum concentrations of sTNFR2 were higher in the uveitis group when compared to the control group (respectively, mean ± SD values, 1734.84±379.32 and 1442.75±309.47; p=0.002). There was no association between the serum levels of the molecules and the time of first symptoms, severity of vitreous haze, size or localization of active lesions, levels of visual acuity, and presence of vasculitis. These results suggest that TR is associated with changes in the circulating levels of inflammatory biomarkers, but they are not correlated with local/ocular signs.

Review for disease of the year: differential diagnosis of ocular toxoplasmosis.

The diagnosis of ocular toxoplasmosis is mainly clinical, based in the presence of focal necrotizing retinochoroiditis often associated with a preexistent chorioretinal scar, and variable involvement of the vitreous, retinal blood vessels, optic nerve, and anterior segment of the eye. Recognition of this clinical spectrum of toxoplasmic retinochoroiditis is crucial, but other infectious, noninfectious, and neoplastic entities should also be considered in the differential diagnosis. Investigations such as serological tests, polymerase chain reaction of ocular fluids, and assessment of intraocular antibody synthesis are helpful in uncertain cases. This article provides an overview of the differential diagnosis of ocular toxoplasmosis, focusing on the most important entities to be considered and emphasizing distinctive features of each one of them in the clinical setting. Ocular toxoplasmosis has multiple clinical manifestations, which partially overlap with those of other entities and these should be carefully considered when making the differential diagnosis, particularly in less typical cases.

Imunologia da retinocoroidite toxoplásmica / Immunology of the toxoplasmic retinochoroiditis

A infecção pelo Toxoplasma gondii é uma importante causa de doença ocular, tanto em indivíduos imunocomprometidos como em imunocompetentes. A patogênese da destruição retinocoroidiana associada a essa infecção ainda não está totalmente esclarecida. Nesta revisão, discute-se o papel do sistema imune no controle da infecção pelo Toxoplasma, especialmente, no olho.

Toxoplasma gondii infection is an important cause of ocular disease in both immunocompromised and immunocompetent subjects. The pathogenesis of retinochoroidal lesion associated with this infection is not fully understood. In this review, the role of the immune system in the control of Toxoplasma infection, especially in the eye, is discussed.

Cat-scratch disease: ocular manifestations and visual outcome.

To describe the intra-ocular manifestations of cat-scratch disease (CSD) found at two uveitis reference centers in Brazil. Retrospective case series study. Review of clinical records of patients diagnosed with CSD in the Uveitis Department of São Geraldo Hospital and the Ophthalmology Department of the Instituto de Pesquisa Clínica Evandro Chagas-FIOCRUZ, from 2001 to 2008. In the 8-year period, 24 patients with the diagnosis of CSD were identified. Twelve patients were male and 12 female. The mean age was 27.04 years (range 7-56). Sixteen patients (66.6%) presented with a history of a cat scratch and all patients reported cat exposure. Visual acuity ranged from counting fingers to 1.0 in the affected eye. Thirteen patients presented with bilateral disease. Sixteen (66.6%) patients complained of systemic symptoms, including fever, lymphadenopathy, liver and spleen enlargement and rash. All patients presented with serum antibodies (IgG) to Bartonella henselae. Thirty-seven eyes were affected. The most common findings were small areas of retinal infiltrates which occurred in 11 eyes (29.7%) and angiomatous lesions which occurred in nine eyes (24.3%). Neuroretinitis occurred in only six eyes (16.2%). The most common findings of CSD in our study were retinal infiltrates and angiomatous lesions. CSD patients may present with significant visual loss. Patients may benefit from systemic treatment with antibiotics.

[Immunology of the toxoplasmic retinochoroiditis]. / Imunologia da retinocoroidite toxoplásmica.

Toxoplasma gondii infection is an important cause of ocular disease in both immunocompromised and immunocompetent subjects. The pathogenesis of retinochoroidal lesion associated with this infection is not fully understood. In this review, the role of the immune system in the control of Toxoplasma infection, especially in the eye, is discussed.