Could different aqueous humor and plasma cytokine profiles help differentiate between ocular sarcoidosis and ocular tuberculosis?

OBJECTIVE AND DESIGN: A cross-sectional single-center study was conducted to assess cytokine levels in aqueous humor (AH) and plasma of three different uveitis entities: definite ocular sarcoidosis (OS), definite OS associated with QuantiFERON®-TB Gold test positivity (Q + OS) and presumed tubercular uveitis (TBU). SUBJECTS: Thirty-two patients (15 OS, 5 Q + OS, 12 TBU) were included. METHODS: Quantification of selected cytokines was performed on blood and AH samples collected before starting any treatment. Statistical analysis was conducted using the Kruskal-Wallis test, the Mann-Whitney or Fisher test and the Principal Component Analysis (PCA). RESULTS: IL-6, IL-8 and IP-10 levels were higher in AH samples than in peripheral blood. In AH samples, BLC, IL-8 and IP-10 were significantly higher in definite OS than in presumptive TBU. There were no statistically significant differences in terms of cytokine levels between Q + OS and presumptive TBU. PCA showed a similar cytokine pattern in the latter two groups (IFNγ, IL-15, IL-2, IP-10, MIG), while the prevalent expression of BLC, IL-10 and MIP-3 α was seen in definite OS. CONCLUSIONS: The different AH and plasma cytokine profiles observed in OS compared to Q + OS and TBU may help to differentiate OS from TBU in overlapping clinical phenotypes of granulomatous uveitis (Q + OS).

Proteomic profile of vitreous in patients with tubercular uveitis.

OBJECTIVE: To elucidate disease-specific host protein profile in vitreous fluid of patients with intraocular inflammation due to tubercular uveitis (TBU). METHODS: Vitreous samples from 13 patients with TBU (group A), 7 with non-TBU (group B) and 9 with no uveitis (group C) were analysed by shotgun proteomics using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). Differentially expressed proteins (DEPs) were subjected to pathway analysis using WEB-based Gene SeT Analysis Toolkit software. RESULTS: Compared to control groups (B + C combined), group A (TBU) displayed 32 (11 upregulated, 21 downregulated) DEPs, which revealed an upregulation of coagulation cascades, complement and classic pathways, and downregulation of metabolism of carbohydrates, gluconeogenesis, glucose metabolism and glycolysis/gluconeogenesis pathways. When compared to group B (non-TBU) alone, TBU displayed 58 DEPs (21 upregulated, 37 downregulated), with an upregulation of apoptosis, KRAS signaling, diabetes pathways, classic pathways, and downregulation of MTORC1 signaling, glycolysis/gluconeogenesis, and glucose metabolism. CONCLUSION: This differential protein profile provides novel insights into the molecular mechanisms of TBU and a baseline to explore vitreous biomarkers to differentiate TBU from non-TBU, warranting future studies to identify and validate them as a diagnostic tool in TBU. The enriched pathways generate interesting hypotheses and drive further research.

Mycobacterium Tuberculosis Modulates Fibroblast Growth Factor and Vascular Endothelial Growth Factor in Ocular Tuberculosis.

Purpose: To evaluate the role of angiogenic growth factors in the pathogenesis of intraocular tuberculosis.Methods: Retinal Pigment Epithelium (RPE) cells were infected with varying dilution of Mycobacterium tuberculosis (MTB), ranging from several thousand to a few MTB bacilli to replicate paucibacillary conditions. Angiogenesis growth factors were evaluated using multiplex fluorescent bead based flow cytometry in the culture supernatant of RPE cells infected with MTB, vitreous fluids and tear samples of uveitis patients visiting retina clinic.Results: Vascular endothelial growth factor (VEGF) levels were elevated and fibroblast growth factors (FGFs) were down regulated in RPE-infected MTB cells. Similar pattern of VEGF and FGF was observed in the vitreous of IOTB patients. However, no changes were observed in tear samples.Conclusions: MTB exploits the angiogenesis growth factors for pathogenesis by decreasing FGF with concomitant surge of VEGF in MTB infected RPE as well in the vitreous of IOTB patients.

A zebrafish model for ocular tuberculosis.

Ocular tuberculosis (TB) commonly causes severe inflammation and vision loss in TB-endemic countries. The mechanism by which tuberculous infection becomes established in the eye is poorly understood. We have developed the zebrafish larva infected with Mycobacterium marinum as a model to study the early pathogenesis of ocular TB. We find that hematogenous bacterial seeding of the eye occurs despite a functional blood retinal barrier. Prototypical early granulomas form in response to bacteria in the eye. These granulomas involve the retinal vasculature and retinal pigment epithelium-choroid complex which are characteristic locations for human ocular TB. We find that peripheral blood monocytes are recruited to the nascent ocular granuloma further suggesting that the immune privileged nature of the eye is breached by this inflammatory focus.

Presumed latent ocular tuberculosis diagnosed with the positive quantiFERON-TB Gold In-Tube Test in a HLA-A29-positive patient.

A 59-year-old Hispanic woman presented with a 3-year history of floaters associated with bilateral reduced visual acuity. Her best-corrected visual acuity (BCVA) was 20/40. Both anterior segments were without inflammation, but fundoscopy showed mild vitreous inflammation and multiple inflammatory choroidal lesions. Tests for inflammatory and infectious diseases were negative except for human leucocyte antigen A29. The patient was diagnosed with birdshot choroidoretinopathy, and treatment was initiated with cyclosporine A 2.5 mg/kg/day. One year after treatment, the patient reported systemic symptoms with no improvement in visual acuity. Fundus findings remained with vitreal inflammation. QuantiFERON-TB Gold In-Tube Test was positive, and a diagnosis of presumed latent ocular tuberculosis (TB) was made. We initiated anti-TB treatment for 9 months. At 6 months of anti-TB therapy, there was no active inflammation. The patient was followed for 2 years with no medications and no active inflammation. Her final BCVA was 20/25.

Patterns of systemic uptake of 18-FDG with positron emission tomography/computed tomography (PET/CT) studies in patients with presumed ocular tuberculosis.

AIM: To report the patterns and sites of 18-FDG uptake in patients of presumed ocular tuberculosis. MATERIALS AND METHODS: The clinical and investigational findings of 11 patients were reviewed retrospectively. These included 6 males and 5 females with a mean age of 46.2 years. 21 eyes were included in the data analysis. Clinical presentations include 15 eyes with anterior uveitis, 2 eyes with retinal vasculitis, 2 eyes with panuveitis and 2 eyes with multifocal choroidopathy. RESULTS: Two distinct patterns of systemic uptake emerged. Pattern 1: No detectable systemic uptake (4 patients). Pattern 2: Detectable systemic uptake. a. Chest disease only (2 patients). b. Disseminated pattern, uptake seen at multiple sites (4 patients). c. Extrapulmonary only (1 patient). CONCLUSIONS: Ocular tuberculosis may often be part of a wider disseminated disease.

Treatment of experimental anterior and intermediate uveitis by a dexamethasone intravitreal implant.

PURPOSE: To assess the efficacy of a dexamethasone (DEX) intravitreal implant in a rabbit model of anterior and intermediate uveitis. METHODS: Experimental anterior and intermediate uveitis was induced by a unilateral intracameral injection of Mycobacterium tuberculosis H37Ra antigen in preimmunized rabbits. Four days after uveitis induction, rabbits received DEX implant or underwent a sham procedure (no implant). Clinical and histopathologic signs of uveitis were assessed for 13 days, and levels of inflammatory markers in the iris/ciliary body were measured after 21 days. RESULTS: All signs of anterior and intermediate uveitis were reduced by the DEX implant compared with sham procedure. At day 13, mean anterior chamber cell scores ± SD for the DEX implant versus the sham procedure were, respectively, 1.9 ± 1.3 versus 4.0 ± 0.0 (P = 0.04), and mean total histologic inflammatory scores were 3.9 ± 2.5 versus 15.4 ± 6.0 (P = 0.026). Similarly, at day 13, mean vitreous haze severity scores (SD) for the DEX implant versus the sham procedure were, respectively, 0.1 ± 0.2 versus 2.7 ± 1.5 (P = 0.026), and mean vitreous inflammatory cell infiltration scores were 0.0 ± 0.0 versus 1.5 ± 1.3. Treatment with the DEX intravitreal implant also significantly reduced the proinflammatory immune response, as measured by cytokine levels in iris/ciliary body. CONCLUSIONS: A single administration of DEX implant significantly reduced inflammation in an animal model of anterior and intermediate uveitis.

A case of immunoglobulin G4-related chronic sclerosing sialadenitis and dacryoadenitis associated with tuberculosis.

We describe a 64-year-old woman with chronic sclerosing sialadenitis and dacryoadenitis, which developed during treatment for cervical lymph node tuberculosis. Anti-tuberculosis treatment did not improve the swelling in the lacrimal and submandibular glands, and a biopsy specimen of the lacrimal gland showed inflammation, with abundant lymphoid follicles with fibrosis and granuloma without caseous necrosis. Immunohistological examination of a repeat biopsy specimen showed abundant immunoglobulin (Ig) G4-positive plasma cell infiltration. Corticosteroid therapy improved the salivary gland swelling without reactivation of the tuberculosis. This case suggests that an abnormal immunological reaction to tuberculosis may be one of the etiological candidates for IgG4-related disease.

QuantiFERON TB-Gold--a new test strengthening long-suspected tuberculous involvement in serpiginous-like choroiditis.

PURPOSE: To obtain a diagnosis of tuberculosis in patients with a specific subset of uveitis, serpiginous-like choroiditis. This subset has been suspicious for tuberculous etiology in single case reports and old textbooks. DESIGN: Retrospective evaluation of a diagnostic test in a specific uveitis cohort. METHODS: QuantiFERON is an approved, antigen-specific test that utilizes synthetic peptides representing Mycobacterium tuberculosis proteins. After incubation, interferon gamma secreted by T lymphocytes in response to these antigens is measured. We used the test in 21 of 26 patients identified from our database with serpiginous-like choroiditis. Rates of QuantiFERON positivity were compared to a group of healthy hospital employees (n = 208), another group of healthy hospital workers after tuberculosis contact (n = 117), and a group of randomly tested patients with other uveitis forms (n = 45). RESULTS: Eleven of 21 serpiginous-like choroiditis patients (52%) were tested positive. The rate of QuantiFERON positivity in the healthy control groups was 8.7% and 0.9%, and 13% in the other uveitis subsets. Four of the QuantiFERON-positive serpiginous-like choroiditis patients were treated with standard anti-tuberculostatic therapy; three finished the course and improved. Seven patients are either stable without therapy (n = 4) or on low-dose prednisone (n = 3). CONCLUSIONS: QuantiFERON testing revealed a high number of positive patients, which indicates a tuberculous etiology in this uveitis subset. Whether bacterial activity or secondary immunologic processes are causative remains a matter of speculation.

Application of nested polymerase chain reaction (nPCR) using MPB 64 gene primers to detect Mycobacterium tuberculosis DNA in clinical specimens from extrapulmonary tuberculosis patients.

BACKGROUND & OBJECTIVE: The conventional culture technique for diagnosis of extrapulmonary tuberculosis is time consuming. In order to find a sensitive and rapid technique nested polymerase chain reaction (nPCR) targeting the conserved MPB 64 gene of Mycobacterium tuberculosis was evaluated for detection of M. tuberculosis DNA directly from clinical specimens of extrapulmonary origin. METHODS: A total of 400 clinical specimens from clinically suspected cases of extrapulmonary tuberculosis and 30 control specimens of nontuberculous aetiology were processed by smear and culture and by nPCR technique for detection of M. tuberculosis. The specimens were divided into 3 groups, (group I--280 specimens [104 peritoneal fluid (PF), 120 cerebrospinal fluid (CSF), 44 lymph node biopsies 3 pericardial fluid and 9 other biopsy specimens], group II--120 aqueous humour (AH) from idiopathic granulomatous uveitis cases, and group III--30 control specimens (10 CSF and 20AH). RESULTS: The conventional culture was positive only in 16 of 400 specimens. The overall positivity of nPCR was 35.2 per cent (141/400). Among the 280 specimens from extrapulmonary lesions (group I), 15 were bacteriologically positive, while 115 of 265 bacteriologically negative specimens (43.4%) were positive by nPCR. All the 30 control specimens were negative by nPCR. INTERPRETATION & CONCLUSION: The nPCR using MPB64 gene primers might be a rapid and reliable diagnostic technique for detection of M. tuberculosis genome in clinically suspected extrapulmonary tuberculosis specimens, as compared to the conventional techniques.