Intraocular manifestations of mycobacterium tuberculosis: A review of the literature

Cytomegalovirus Retinitis: Clinical Manifestations, Diagnosis and Treatment

Cytomegalovirus (CMV) retinitis is the most common eye disease associated with CMV infection in immunocompromised individuals. The CMVR may initially be asymptomatic; however, relatively mild vitreous inflammation at the onset may be an important differential point from other diseases in HIV patients. Fundus photography, CD4 T-cell count, and telemedicine could be used to screen and monitor the high-risk population, particularly in resource-limited regions. Retinitis generally starts in the peripheral retina and advances toward the posterior pole, which could develop to the characteristic "pizza pie" appearance marked by central retinal necrosis and intraretinal hemorrhage. CMVR causes vision loss if left untreated, and early antiviral therapy significantly reduces the risk of vision loss. Alongside traditional antiviral treatments, immunotherapies including CMV-specific adoptive T-cell therapy and CMV immunoglobulin (CMVIG) are emerging as promising treatment options due to their favorable tolerability and reduced mortality. This review comprehensively examines CMV retinitis, encompassing the clinical features, differential diagnosis, laboratory tests, and updated treatment strategies to inform clinical management.

SUBFOVEAL CHOROIDAL TUBERCULOMA IN A HEALTHY YOUNG WOMAN CAUSED BY MYCOBACTERIUM BOVIS

PURPOSE

To describe a case of a macular tuberculoma in a young and healthy woman after developing a tuberculous lymphadenitis caused by Mycobacterium bovis .

METHODS

Retrospective case report.

RESULTS

Tuberculous lymphadenitis caused by M. bovis was detected after biopsy and histological examination as well as polymerase chain reaction test testing of cervical lymph nodes in a 20-year-old patient. An interferon gamma was positive. Shortly starting antitubercular therapy, the patient developed visual deterioration caused by a single yellowish subretinal structure in the macula of the right eye. Optical coherence tomography showed a dome-shaped, hyperreflective, subfoveal choroidal lesion with subtle subretinal fluid. Antitubercular therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide was performed, and the deescalation therapy with isoniazid and rifampicin was extended to 7 months. Further examinations showed regression of choroidal tuberculoma to a scar.

CONCLUSION

This is the first reported case of choroidal tuberculoma after tuberculous lymphadenitis caused by M. bovis .

Intraocular tuberculosis masquerading as ocular tumor: A case report

Tuberculosis is one of the most common pediatric problems, especially in the developing world. In spite of that, intraocular tuberculosis is a rare disease that can easily be confused with other noninfectious processes, even in regions where tuberculosis is rampant. Diagnosis is difficult, yet it is very important to provide effective antituberculosis treatment and avoid potentially sight-losing interventions. We present a case of a 2-year-old child with a positive contact history of tuberculosis who presented with progressively worsening seizures and constitutional symptoms for 6 months. Brain computed tomography revealed right frontotemporal region conglomerated ring-enhancing lesions with central necrosis consistent with tuberculosis. On the same scan, a calcified right retinal lesion with a contrast-enhancing soft tissue component was identified. A chest radiograph and abdominal sonography showed evidence of disseminated tuberculosis. Subsequently, antituberculosis treatment was initiated, and the right retinal lesion improved, thus leading to the imaging diagnosis of right intraocular tuberculosis. Early and accurate diagnosis of retinal tuberculosis is of paramount importance in avoiding potentially catastrophic interventions. Neuroimaging is a useful, noninvasive method to consider this difficult diagnosis and also for follow-up.

TUBERCULOUS CHORIORETINITIS: A CHALLENGING CASE OF AN OPHTHALMIC MIMIC

PURPOSE

To report a challenging case of tuberculous chorioretinitis.

METHODS

Case report of a 51-year-old woman from the Middle East, who was referred from an optometrist with a suspicious retinal lesion in her right eye.

RESULTS

Clinical examination showed multifocal, pale, elevated lesions temporal to the right macula with no vasculitis or hemorrhages. Infective and inflammatory workup showed unremarkable results. B-scan ultrasound confirmed an 8 mm × 3 mm × 10 mm right focal chorioretinal thickening. Computed tomography scanning showed calcified lung hilar nodes supporting a prior granulomatous process, along with an enhancing nodule in the right globe. Magnetic resonance imaging of the brain and obits showed retinal thickening of the temporal surface of the right globe with subtle enhancement without retrobulbar extension or evidence for cerebral vasculitis. Subretinal lesion biopsy showed mononuclear inflammatory cells with granulomatous inflammation, including multinucleated giant cells but no neoplastic features. Interferon-gamma release assay testing for tuberculosis showed negative result, but a high index of suspicion lead to tuberculin skin testing and subsequent treatment for tuberculous chorioretinitis.

CONCLUSION

Ocular tuberculosis presents in a variety of ways, making it a challenging diagnosis. Herein, we describe such case of tuberculous chorioretinitis.

Disseminated tuberculosis presenting as bilateral neuro-retinitis

Disseminated tuberculosis (TB) presenting with intraocular involvement is a rare condition, which can lead to profound visual loss if misdiagnosed. We report a case of a 24-year-old Nepalese male with disseminated TB who presented primarily with bilateral vision loss.

Tubercular Retinal Vasculitis: Diagnostic Dilemma and Management Strategies

Ocular tuberculosis (OTB) is a rare, extrapulmonary manifestation of systemic TB, which has been a global etiology of uveitis for centuries, though concentrated in the developing world. OTB remains difficult to diagnose clinically despite a plethora of conventional and modern investigations. Tubercular retinal vasculitis (TRV) is a common and specific presentation of OTB but is variably defined in the literature in terms of clinical profile and the investigations essential for diagnosis and treatment. Ironically, the need and duration of antitubercular treatment is uncertain for this manifestation of ocular TB. The rationale and utility for corticosteroids is similarly equivocal for TRV. This review attempts to tease out a commonsense approach from the best available evidence and consensus in the literature to suspect, investigate and diagnose TRV with reasonable certainty, and institute appropriate treatment with due ethnic and geographic considerations.

Dysregulated expression of microRNAs in aqueous humor from intraocular tuberculosis patients

BACKGROUND

Systemic Mycobacterium tuberculosis (Mtb) infection alters microRNA's expression that controls cellular processes and modulates host defense mechanisms. However, the role of miRNAs in intraocular tuberculosis (IOTB) remains unknown. Therefore, this study aims to identify dysregulated miRNAs in the aqueous humor (AH) of patients with IOTB.

METHODS

AH from intraocular tuberculosis patients (n = 2) and cataract controls (n = 2) were used for small RNA deep sequencing using HiSeq Illumina sequencing platform. Differentially expressed miRNAs and their targets were identified by the bioinformatics approach, and their regulatory functions were predicted by pathway enrichment analysis. The expression of selected miRNAs and their binding targets were further validated by real-time quantitative PCR (RT-qPCR).

RESULTS

In total, we identified 56 differentially expressed miRNAs in the AH of intraocular tuberculosis (IOTB) patients compared to controls. We selected four significantly dysregulated miRNAs (miR-423-5p, miR-328-3p, miR-21-5p, and miR-16-5p) based on the RT-qPCR validation and predicted their gene targets. We developed a miRNA-targets regulatory network by combining pathways of interest and genes associated with TB. We identified that these four miRNAs might play an important role in IOTB pathogenesis via tuberculosis-associated pathways; PI3K-Akt signaling, autophagy and MAPK pathway.

CONCLUSIONS

For the first time, this study identifies the dysregulation of four miRNAs in the AH of IOTB patients using the ultra-low input small-RNA sequencing approach. Further target prediction and validation identify the role of these miRNAs in tuberculosis pathogenesis via tuberculosis-related pathways. This study identifies miRNAs as potentially ideal biomarkers in the aqueous humor of IOTB patients.

The diagnostic value of polymerase chain reaction for ocular tuberculosis diagnosis in relation to antitubercular therapy response: a meta-analysis

BACKGROUND

Polymerase chain reaction (PCR) is currently considered the method of choice for diagnosing ocular tuberculosis. However, the sensitivity and specificity of PCR using ocular samples remain uncertain. Our meta-analysis aimed to review the diagnostic accuracy of PCR testing in confirming ocular tuberculosis, with responses to antitubercular therapy (ATT) as reference indices.

METHODS

A systematic literature search of the PubMed, EBSCOHost, Scopus, and Google Scholar databases was performed using the standardized PRISMA guideline. Observational studies reporting both PCR MTb positivity and ATT response were included. Meta-analysis was performed to estimate the pooled positivity rate, sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios (DOR), and summary receiver operating curves (SROC).

RESULTS

The pooled positivity rate for PCR MTb was 0.55 (95% CI 0.44-0.67). The overall sensitivity and specificity were 88% (95% CI 83-92) and 71% (95% CI 60-80), respectively. The pooled DOR was 12.15 (95% CI 5.55-26.62). The area under the SROC was 0.83.

CONCLUSIONS

The diagnostic accuracy of PCR Mtb is not sufficient for use as a benchmark for ocular TB diagnosis routinely based on ATT response. A negative result may help avoid prescribing unnecessary ATT in dilemmatic cases.

Tuberculosis-Related Uveitis in Patients under Anti-TNF-alpha Therapy: A Case Series

Tumor necrosis factor inhibitors (anti-TNF) have emerged as an effective treatment in noninfectious uveitis (NIU). Anti-TNF may increase the predisposition to infectious disease as tuberculosis (TB). TB-related uveitis in the context of an uveitogenic concurrent systemic immune-mediated disease under anti-TNF treatment remain a diagnostic challenge, deserving special focus on this rare context. Retrospective chart review of patients on anti-TNF drugs for systemic immune-mediated diseases that developed a multicentric microbiologically confirmed active TB with concurrent intraocular involvement.Three patients were recorded. Screening for TB before starting anti-TNF resulted negative in two patients. The other patient had received anti-tuberculous treatment in the past. All showed a microbiologically confirmed extraocular TB after unexpected atypical reactivation of the uveitis shifting to chronic granulomatous pattern.Specialists should be aware of TB reactivation, even with previous negative screening, when ocular uveitis signs and activity do not match with the expected pattern in a patient on anti-TNF drugs.

Endogenous Tuberculous Endophthalmitis and Panophthalmitis: A Systematic Review of Case Reports and Case Series

Purpose

To systematically review the characteristics of patients with endogenous tuberculous (TB) endophthalmitis and panophthalmitis in an effort to help clinicians with diagnosis and treatment.

Patients and Methods

We conducted a systematic literature search in MEDLINE/PubMed, EMBASE and Web of Science from inception to August 2020. References and abstracts were screened independently by two authors. Included studies were case reports and case series reporting endogenous TB endophthalmitis and panophthalmitis secondary to Mycobacterium tuberculosis complex (MTBC). Available-case analysis was employed to handle missing data.

Results

A total of 1343 articles were found using the search strategy. Following abstract screening, 51 articles were selected for full text-review, from which 26 were deemed eligible for inclusion in the study. Forty-four cases from 26 articles were included in the quantitative analysis. The median age of presentation was 29.5 (range: 1 to 81), and 11/44 patients (25.0%) were pediatric. Immunosuppression was seen in 9/36 cases (25.0%). Most patients (24/38, 63.2%) had no prior history of tuberculosis. Systemic symptoms were absent in half of the patients (16/32, 50.0%). Visual acuity was poor, with 23/27 cases (85.2%) being 20/200 or worse at presentation. Poor organ and visual outcomes were reported: 36/43 cases (83.7%) resulted in enucleation/evisceration or exenteration. Intraocular tumors were suspected in 5/34 cases (14.7%). Pulmonary tuberculosis was seen in 15/35 cases (42.8%), and miliary tuberculosis was seen in 7/35 cases (20.0%). The earliest source of TB diagnosis was through histopathologic specimen after eye removal in 32/44 cases (72.7%), vitreous specimen in 6/44 cases (13.6%) and aqueous specimen in 3/44 cases (6.8%).

Conclusion

TB endophthalmitis is a rare and sight-threatening manifestation of ocular tuberculosis. It can occur in apparently healthy individuals and can mimic intraocular tumors and other infectious etiologies. Diagnosis remains a significant challenge, which, often delayed, leads to profound visual loss. Early detection and treatment of intraocular tuberculosis may be associated with better ocular and systemic outcomes.

Inverse correlation between serum complement component C1q levels and whole blood type-1 interferon signature in active tuberculosis and QuantiFERON-positive uveitis: implications for diagnosis

Objectives

To examine the relation between serum C1q levels and blood type‐1 interferon signature (type‐1 IFN signature) in active pulmonary tuberculosis (APTB) and to determine whether combined measurement of serum C1q and type‐1 IFN signature may add to the diagnosis of QuantiFERON‐positive (QFT⁺) patients with uveitis of unknown cause.

Methods

C1q was determined (ELISA) in serum from two distinct Indonesian cohorts, and in total, APTB (n = 72), QFT⁺ uveitis of unknown aetiology (n = 58), QFT⁻ uveitis (n = 51) patients and healthy controls (HC; n = 73) were included. The type‐1 IFN signature scores were previously determined.

Results

Serum C1q was higher in APTB than HC (P < 0.001). APTB patients with uveitis had higher serum C1q than APTB patients without uveitis (P = 0.0207). Serum C1q correlated inversely with type‐1 IFN signature scores in APTB (P = 0.0036, r² = 0.3526), revealing that these biomarkers for active TB disease can be mutually exclusive. Stratification of QFT⁺ patients with uveitis of unknown cause, by serum C1q and type‐1 IFN signature, yielded four groups with different likelihood of suffering from active TB uveitis.

Conclusion

Serum C1q is elevated in APTB, especially in those cases with uveitis. We propose that combined measurement of blood type‐1 IFN signature and serum C1q may provide added value in the diagnosis of active TB disease. Combined measurement of type‐1 IFN signature and serum C1q in QFT⁺ patients without signs of active TB disease, but suffering from uveitis of unknown cause, may be of help to identify cases with low or high likelihood of having active TB uveitis, which may facilitate clinical management decisions.

"There is more than what meets the eye" - Extensive spinal tuberculosis presenting as ocular tuberculosis

Ocular tuberculosis (OTB) is a rare form of extrapulmonary Tuberculosis (EPTB) and a rare presenting feature of tuberculosis (TB) in children. We report such a case in a 3-year-old boy who presented with a painless swelling over left upper eyelid. Mycobacterium tuberculosis bacilli were isolated from the swelling by a Fine Needle Aspiration Cytology (FNAC) which confirmed the diagnosis. Investigating him for the extent of disease, we found him to have intracranial extension to involve the ethmoid sinus on contrast enhance Computed Tomography and Pott's disease causing a compression fracture of L3 with bilateral paravertebral collection, epidural extension and a left psoas abscess on Magnetic Resonance Imaging. After starting antitubercular therapy, the child is doing well and on regular follow up. We are presenting this case to highlight the fact that extensive spinal tuberculosis can present without any neurological deficit and may even present only as a benign looking orbital swelling.

Tuberculous choroiditis masquerading as sympathetic ophthalmia: a case report

A 26-year-old Chinese man was admitted to this clinic due to decreased vision in his right eye for 4 days and painful protrusion in his left eye for 20 days. He had no perception of light in his left eye and perception of hand motion (HM) in his right eye. Examinations revealed that the left eye's lens and iris had protruded, and corneoscleral perforation. The right eye had an anterior chamber reaction and severe exudative retinal detachment that were confirmed by fluorescein angiography. Systemic examinations failed to identify a cause. The presumptive diagnosis was sympathetic ophthalmia of the right eye. Therefore, systemic steroid treatment was administered and enucleation of the left eye was performed. Although steroid treatment had been initiated, exudative detachment did not vary markedly. A pathological examination of the left eye revealed ocular tuberculosis, and anti-tuberculosis treatment resulted in a gradual reduction in subretinal fluid as well as improved vision.

Ocular tuberculosis epidemiology, clinic features and diagnosis: A brief review

The spread of tuberculosis is directly related to the processes of globalization and migration. Tuberculosis has also been the main cause of fatality associated with antimicrobial resistance and also the main cause of death in people who have HIV infection. Additionally, tuberculosis smites the lungs in 80% of patients, and in the remaining 20% of patients the tuberculosis may smites other organs, such as the vision/eye. Ocular tuberculosis is a specific infectious disease of bacterial etiology with a chronic and persistent course, the prognosis of which is extremely doubtful. Even effective chemotherapy can be accompanied by a decrease in visual acuity, and clinical recovery is not always persistent. Ocular tuberculosis often leads to permanent disability and, as a result, the quality of life of patients decreases. A statistical reporting of this disease does not always reflect the true picture, since ocular tuberculosis sometimes develops against the background of an existing specific lesion in the lung tissue. Currently, ocular tuberculosis remains substantially a conjectural clinical diagnosis. This review paper presents an analytical review of the literature on the epidemiology, clinical features, and diagnosis methods of ocular tuberculosis. The results of recent studies that focused on the modern clinical manifestations of this pathology, its diagnosis, and complex therapy are systematized. The development of new rational regimens and pathogenetic treatment methods are also highlighted in this review.

Presumed ocular tuberculosis in the United Kingdom: a British Ophthalmological Surveillance Unit (BOSU) study

Introduction

Ocular tuberculosis (TB) is an extrapulmonary manifestation of mycobacterium infection that most commonly presents as uveitis. This is the first prospective incidence study of presumed ocular tuberculosis performed in the United Kingdom (UK).

Method

New cases of ocular tuberculosis presenting to hospitals in the UK were prospectively ascertained between October 2016 and November 2017 with the aid of the British Ophthalmological Surveillance Unit (BOSU). Initial presentation data and 1-year follow-up data was collected using questionnaires.

Results

Forty-eight patients were recruited giving an overall incidence for ocular TB of 0.73 per million population per annum. The origin of birth for 71% of the patients was a non-UK country and 87.5% had their initial diagnosis of TB made by an ophthalmologist. The most common first line treatment was isoniazid, rifampicin, ethambutol and pyrazinamide which 71% of patients were treated with 60% of patients were commenced on a reducing course of oral steroids. At 1-year follow-up, 29 patients (83%) had complete resolution of active clinical signs. Mean best corrected visual acuity (BCVA) at presentation was +0.41 LogMAR(SD = 0.62), compared to +0.31 LogMAR (SD = 0.56) at 12-month follow-up.

Discussion

It is increasingly the responsibility of the ophthalmologist to diagnose ocular TB and although it remains a rare condition, consensus on diagnostic criteria and treatment is required. Increasing recognition and accessibility to gamma-interferon testing should enable earlier detection. Treatment with quadruple ATT treatment regimens for at least 6 months shows good clinical outcomes. However, it is still unclear whether steroid use is beneficial. Further large studies with longer follow-up would be warranted to answer these questions.

Tuberculous Uveitis, Erythema Induratum, and Persistent Genital Warts in a Female Patient: A Rare Case Report

Uveitis and erythema induratum are two uncommon extrapulmonary manifestations of tuberculosis (TB). In most circumstances, we cannot isolate mycobacterium from those sites, so diagnosis is difficult. In the presented case, panuveitis, erythema induratum, and persistent anogenital warts were found concurrently in a 19-year-old girl who had a history of pulmonary TB 10 years ago. Assessment of her immune condition ruled out any immunodeficiency state. Extrapulmonary TB and persistent warts responded dramatically to anti-TB drugs and interferon-gamma, respectively. Our case reveals that a constellation of these clinical manifestations may also occur in immunocompetent individuals.

Severe disseminated tuberculosis in HIV-negative refugees

In high-income countries, the presentation of tuberculosis is changing, primarily because of migration, and understanding the specific health needs of susceptible populations is becoming increasingly important. Although disseminated tuberculosis is well documented in HIV-positive patients, the disease is poorly described and less expected in HIV-negative individuals. In this Grand Round, we report eight HIV-negative refugees, who presented with extensively disseminated tuberculosis. We discuss the multifactorial causes, such as deprivations during long journeys, precarious living conditions, and the experience of violence, which might add to nutritional factors and chronic disorders, eventually resulting in a state of predisposition to immune deficiency. We also show that disseminated tuberculosis is often difficult to diagnose when pulmonary symptoms are absent. Communication difficulties between refugees and health-care workers are another major hurdle, and every effort should be made to get a valid patient history. This medical history is crucial to guide imaging and other diagnostic procedures to establish a definite diagnosis, which should be confirmed by a positive tuberculosis culture. Because many of these patients are at risk for multidrug-resistant tuberculosis, drug susceptibility testing is imperative to guide therapy. In the absence of treatment guidelines for this entity, clinicians can determine treatment duration according to recommendations provided for extrapulmonary tuberculosis and affected organs. Paradoxical expansion of tuberculous lesions during therapy should be treated with corticosteroids. In many cases, treatment duration must be individualised and might even exceed 12 months.

Solid lipid nanoparticles for ocular delivery of isoniazid: evaluation, proof of concept and in vivo safety & kinetics

AIM

Evaluation of solid lipid nanoparticles (SLNs) for ocular delivery of isoniazid (INH).

MATERIALS & METHODS

INH-SLNs were characterized for morphological, thermal, crystalline and nuclear magnetic resonance properties. In vitro release and ex vivo corneal permeability of INH-SLNs was also evaluated. Proof-of-concept uptake studies were performed in corneal and conjunctival cell lines and in vivo in rat eye using fluorescein-labeled SLNs. Antimycobacterial activity of INH-SLNs was confirmed. In vivo aqueous humor pharmacokinetics, toxicity and tolerance was performed in rabbit/rat eye.

RESULTS

INH-SLNs showed extended release (48 h), enhanced corneal permeability (1.6-times), five-times lower MIC, significant in vitro and in vivo uptake of fluorescein-labeled SLNs, 4.2-times ocular bioavailability (area under the curve) and in vivo acute and repeat dose safety.

CONCLUSION

INH-SLNs are an effective ocular delivery system.

Transcriptional Profile of Mycobacterium tuberculosis in an in vitro Model of Intraocular Tuberculosis

Background: Intraocular tuberculosis (IOTB), an extrapulmonary manifestation of tuberculosis of the eye, has unique and varied clinical presentations with poorly understood pathogenesis. As it is a significant cause of inflammation and visual morbidity, particularly in TB endemic countries, it is essential to study the pathogenesis of IOTB. Clinical and histopathologic studies suggest the presence of Mycobacterium tuberculosis in retinal pigment epithelium (RPE) cells. Methods: A human retinal pigment epithelium (ARPE-19) cell line was infected with a virulent strain of M. tuberculosis (H37Rv). Electron microscopy and colony forming units (CFU) assay were performed to monitor the M. tuberculosis adherence, invasion, and intracellular replication, whereas confocal microscopy was done to study its intracellular fate in the RPE cells. To understand the pathogenesis, the transcriptional profile of M. tuberculosis in ARPE-19 cells was studied by whole genome microarray. Three upregulated M. tuberculosis transcripts were also examined in human IOTB vitreous samples. Results: Scanning electron micrographs of the infected ARPE-19 cells indicated adherence of bacilli, which were further observed to be internalized as monitored by transmission electron microscopy. The CFU assay showed that 22.7 and 8.4% of the initial inoculum of bacilli adhered and invaded the ARPE-19 cells, respectively, with an increase in fold CFU from 1 dpi (0.84) to 5dpi (6.58). The intracellular bacilli were co-localized with lysosomal-associated membrane protein-1 (LAMP-1) and LAMP-2 in ARPE-19 cells. The transcriptome study of intracellular bacilli showed that most of the upregulated transcripts correspond to the genes encoding the proteins involved in the processes such as adherence (e.g., Rv1759c and Rv1026), invasion (e.g., Rv1971 and Rv0169), virulence (e.g., Rv2844 and Rv0775), and intracellular survival (e.g., Rv1884c and Rv2450c) as well as regulators of various metabolic pathways. Two of the upregulated transcripts (Rv1971, Rv1230c) were also present in the vitreous samples of the IOTB patients. Conclusions:M. tuberculosis is phagocytosed by RPE cells and utilizes these cells for intracellular multiplication with the involvement of late endosomal/lysosomal compartments and alters its transcriptional profile plausibly for its intracellular adaptation and survival. The findings of the present study could be important to understanding the molecular pathogenesis of IOTB with a potential role in the development of diagnostics and therapeutics for IOTB.

Diminished TLR2-TLR9 mediated CD4+ T cell responses are associated with increased inflammation in intraocular tuberculosis

Intraocular tuberculosis (IOTB) is amongst the leading causes of uveitis in tropical countries. Despite reports on involvement of proinflammatory cytokines, studies on innate immune responses in disease pathogenesis are lacking. Reports from animal models and patients with pulmonary tuberculosis indicate that defects in toll like receptor (TLR)2 and TLR9 signalling predispose them to tuberculosis. In this context, we investigated the role of TLR2, TLR4 and TLR9 in generation of CD4+ T effector (Teff) cell responses during IOTB. Firstly, the cells in vitreous fluids showed lower expression of TLR2 and TLR9 in IOTB as compared to non-uveitis and non-TB uveitis groups. Next, peripheral CD4+ Teff cells of subjects with IOTB showed decreased proliferative responses and lower induction of Tregs following TLR2 and TLR9 stimulation. Further, TLR9 ligation resulted in increased IFN-γ and IL-17a but decreased expression of IL-10 and TGF-β. Lastly, lower expression of genes involved in TLR9 signalling after direct TLR9 ligation was observed in IOTB. Collectively, our results show that a subdued response to direct TLR2 and TLR9 stimulation in CD4+ T cells is associated with increased proinflammatory responses in IOTB. These findings reveal an important link between innate immune signalling and ensuing adaptive immune responses in IOTB with implications in other forms of extrapulmonary tuberculosis.