Unfolding COVID-19: Lessons-in-Learning in Ophthalmology.

IMPORTANCE: An observant Chinese doctor Li Wenliang became the first physician to alert the world about COVID-19. Being an ophthalmologist himself, he has put the additional onus on us. The fact that the ocular manifestation could be the first presenting feature of novel coronavirus pneumonia should not be ignored and the possibility of spread of SARS-CoV-2 through the ocular secretions cannot be ruled out. However, with breakthroughs still evolving about this disease, the calls are now louder for closer examination on the pathogenesis of conjunctivitis associated with it. Hence, we conducted a scoping review of all available literature till date to fill in the "potential" gaps in currently available knowledge on ocular manifestations of SARS-CoV-2 infection in an attempt to establish continuity in the "chain of information" from December 2019 till April 2020. We also summarize a possible hypothesis on much less understood and highly debated topics on regard to the etiopathogenesis of ocular involvement in SARS-CoV-2 based on either presence or absence of ACE2 receptor in the ocular surface. METHODS: We conducted a scoping review search of published and unpublished SARS-CoV-2-related English language articles from December 2019 till mid of April 2020 from the online databases. The findings were summarized using text, tables, diagrams, and flowcharts. RESULTS: The commonest ocular manifestation in SARS-CoV-2 infection is follicular conjunctivitis and has been the first manifestation of SARS-CoV-2 infection in 3 reported cases till date. The ocular surface inoculated with the SARS-CoV-2 leads to the facilitation of the virus to the respiratory system via the lacrimal passage. RT-PCR analysis of the ocular secretions has shown the presence of the SARS-CoV-2 nucleotides indicating the possibility of infection of ocular secretions. ACE2 receptors and its expression on the ocular mucosal surface are linked behind the etiopathogenesis of conjunctivitis. CONCLUSION: Conjunctivitis can be the presenting manifestation but may go unnoticed due to its mild nature. The ocular surface could serve as the entry gateway for the virus and ocular secretions could play a role in virus shed. The eye care personnel, as well as the general people, need to be more vigilant and adopt protective eye measures.

Outcome of polymerase chain reaction (PCR) analysis in 100 suspected cases of infectious uveitis.

BACKGROUND: Polymerase chain reaction (PCR) analysis is an important tool in the diagnosis of infectious uveitis. A retrospective, interventional study of PCR analysis of ocular fluid in suspected infectious uveitis cases between January 2014 to July 2016 was done. Nested, real-time and broad range PCR was performed for detection of the genome of Mycobacterium tuberculosis, herpes virus family, Chikungunya virus, Toxoplasma gondii, fungus, eubacterium and propionibacterium acne. RESULTS: Total of 100 cases included, mean age was 39.2 ± 15.4 years. Uveitis was unilateral in 82% and granulomatous in 40%. Mean visual acuity at the initial visit and final visit was 0.73 logMar and 0.63 logMar respectively. PCR analysis confirmed the clinical diagnosis in 70.1% patients. The sensitivity, specificity, positive predictive value and negative predictive value of PCR analysis was 90.2%, 93.9%, 93.9% and 90.2% respectively. The quantitative value of real-time M. tb. Positive PCR ranged from 32c/ml to 2722 c/ml. CONCLUSIONS: PCR assay is an accurate technique with high sensitivity and specificity to diagnose the DNA genome in infectious uveitis.

Infectious chorioretinitis in an immunocompetent patient: A diagnostic dilemma.

A 44-year-old male presented with a history of defective vision in the right eye for the past 5 months with the previous history of tubercular cervical lymphadenitis. On examination, right eye revealed panuveitis with dense vitritis and chorioretinitis in the superotemporal quadrant. His Mantoux test was positive (25 mm × 25 mm induration), QuantiFERON-TB Gold was test positive, aqueous aspirate was positive for Mycobacterium tuberculosis genome, negative for viruses and toxoplasma, and hence he was initiated on four-drug antitubercular therapy (ATT) with oral steroids. On follow-up, he had worsening of vitritis and intravenous methylprednisolone was given suspecting paradoxical reaction to ATT; however, a repeat AC tap was positive for toxoplasma B1 genome, IgG antitoxoplasma antibody was also positive in serum and aqueous; hence, we switched to systemic antitoxoplasma therapy. He underwent a therapeutic vitrectomy along with intravitreal clindamycin and dexamethasone for persistent vitreous membranes and vitritis. The patient responded well to the treatment with a reduction in vitritis and scarring of the lesion.

Internalisation of hepatitis C virus core protein by human conjunctival fibroblasts.

Recent studies indicate that hepatitis C virus (HCV) proteins can mediate innate immune response and inflammation in conjunctival fibroblasts which contributes to the pathology of dry eye condition associated with chronic HCV infection. The present study investigates the phagocytic potential of human conjunctival fibroblasts (HCFj) for HCV core protein. HCFj cells were incubated with HCV core antigen for different periods of time, and fluorescent micrographs were taken to observe protein internalisation. HCFj cells were capable of internalising HCV core antigen within 1 h; this gives an insight into another molecular mechanism which may contribute towards HCV-associated conjunctival inflammation.

Multilevel Precision-Based Rational Design of Chemical Inhibitors Targeting the Hydrophobic Cleft of Toxoplasma gondii Apical Membrane Antigen 1 (AMA1).

Toxoplasma gondii is an intracellular Apicomplexan parasite and a causative agent of toxoplasmosis in human. It causes encephalitis, uveitis, chorioretinitis, and congenital infection. T. gondii invades the host cell by forming a moving junction (MJ) complex. This complex formation is initiated by intermolecular interactions between the two secretory parasitic proteins-namely, apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2) and is critically essential for the host invasion process. By this study, we propose two potential leads, NSC95522 and NSC179676 that can efficiently target the AMA1 hydrophobic cleft, which is a hotspot for targeting MJ complex formation. The proposed leads are the result of an exhaustive conformational search-based virtual screen with multilevel precision scoring of the docking affinities. These two compounds surpassed all the precision levels of docking and also the stringent post docking and cumulative molecular dynamics evaluations. Moreover, the backbone flexibility of hotspot residues in the hydrophobic cleft, which has been previously reported to be essential for accommodative binding of RON2 to AMA1, was also highly perturbed by these compounds. Furthermore, binding free energy calculations of these two compounds also revealed a significant affinity to AMA1. Machine learning approaches also predicted these two compounds to possess more relevant activities. Hence, these two leads, NSC95522 and NSC179676, may prove to be potential inhibitors targeting AMA1-RON2 complex formation towards combating toxoplasmosis.

Serum-derived hepatitis C virus 1a infection of human astrocyte cell line SVG.

Neuroinvasion of hepatitis C virus (HCV) is evidenced by recent clinical studies. In this study, serum-derived HCV infection of astrocytes was analysed. Astrocytes were infected with HCV-positive serum, and viral replication was assessed on different days postinfection. RT-PCR was positive for HCV-negative strand on 5th and 7th day postinfection in the HCV-positive serum-infected astrocytes. Real-time RNA count in the cell culture supernatant was steadily increasing from day 3 to day 7. To reconfirm the viral replication, astrocytes were treated with an antiviral before the serum infection, and the antiviral treatment significantly reduced the viral RNA count. Further, the virus-infected cells stained positive for the presence of viral core protein. Electron microscopy revealed the presence of HCV-like particles in the astrocyte cell culture supernatant. In conclusion, serum-derived HCV replicates in human astrocyte cell line SVG.

Mebiolgel, a thermoreversible polymer as a scaffold for three dimensional culture of Huh7 cell line with improved hepatocyte differentiation marker expression and HCV replication.

PURPOSE: A novel three dimensional (3D) culture system purely synthesised from co-polymer which is free from biological contamination for Huh7 cell cultivation and hepatitis C virus (HCV) replication has been attempted. MATERIALS AND METHODS: Mebiolgel, a thermo-reversible gelation polymer was used as a 3D scaffold for culturing Huh7, a liver carcinoma cell line used in our study. The 3D culture of the cells were infected with cell culture derived HCV. RESULT: The scaffold supported the cell growth as 3D spheroids for up to 63 days. Moreover mebiolgel was found to be improving the hepatocyte differentiation of Huh7 cells at the transcript level. Three dimensional culture was susceptible for HCV infection, and this was confirmed by detecting the HCV replication intermediate viral core antigen. CONCLUSION: Mebiolgel based culture system was proven to be suited for 3D culture of Huh7 cells by improvising liver specific genotypic expression and was susceptible for HCV replication. Since mebiolgel based Huh 7 express better hepatocyte differentiation markers genotypically, this can be implemented as an alternate for primary hepatocytes in studies such as viral isolation from patient serum.

Optimisation and analysis of polymerase chain reaction based DNA sequencing for genotyping polyoma virus in renal transplant patients: a report from South India.

PURPOSE: To optimise a polymerase chain reaction (PCR) based DNA sequencing technique for genotyping polyoma virus in clinical specimens obtained from renal transplant patients. MATERIALS AND METHODS: A hundred and thirty (106 peripheral blood and 24 urine) clinical specimens collected from renal transplant patients were included in the study for detecting the presence of  DNA of BK virus (BKV), JC virus (JCV) by PCR targeting the viral protein 1 (VP1) gene. PCR based DNA sequencing was performed to determine the genotypes of polyoma virus and subjected to bioinformatics analysis to determine the amino acid sequences and screen for mutations in the VP1 gene. RESULTS: Polyoma virus was detected in 23 (17.69%) specimens of which 19 (82.60%) were positive for BK virus, 3 (13.04%) for JC virus and 1 for both BK and JC virus. PCR based DNA sequencing detected BK virus genotype I in 12 (50%), genotype IV in 8 (33.3%) and JC virus in 4 (16.6%) clinical specimens. BKV genotype I was the predominant genotype (64.2% in peripheral blood and 33.33% in urine) prevalent in south India. Six novel mutations were found--at position 29, 30 to 47 of BKV genotype I; at position 11 and 15 of BKV genotype IV and at position 2 and 30 of JCV. CONCLUSION: BKV genotype I is the prominent genotype in India and novel mutations detected in the VP1 gene of BKV and JCV are being reported for the first time in literature.

A pilot study on expression of toll like receptors (TLRs) in response to herpes simplex virus (HSV) infection in acute retinal pigment epithelial cells (ARPE) cells.

INTRODUCTION: Toll like receptors (TLRs) have been proven to play an important role in mounting the innate immune response in an infected host. The expression of TLRs against herpes simplex virus (HSV) have not been studied in retinitis. Therefore, the current study was undertaken to determine the same using the retinal pigment epithelial (ARPE-19) cell line. MATERIALS AND METHODS: APRE cells cultured in vitro were challenged with HSV 1 and 2 standard strains and 20 other clinical isolates. The cells were observed for cytopathic changes. The cell culture harvest was subjected to RNA extraction using a Total RNA mini kit. The RNA was subjected to reverse transcriptase polymerase chain reaction (PCR) for the amplification of TLRs 3, 4 and 9 and GAPDH housekeeping gene. The amplified products were subjected to electrophoresis on a 2% agarose gel and viewed under a transilluminator. RESULTS: TLR 3 and 4 were expressed by ARPE treated with all the 22 isolates. TLR 9 expression was seen in 16 of the 22 isolates. Bacterial contamination was ruled out by subjecting the harvests to PCR amplification of 16sRNA gene amplification of the eubacterial genome. CONCLUSIONS: The expression of TLR 4 has been reported for the first time in HSV infection. TLR 4 along with TLR 3 and 9 is responsible for the antiviral response in HSV infections.

Draft Genome Sequence of Multidrug-Resistant Mycobacterium tuberculosis Strain CWCFVRF MDRTB 670, Isolated from the Sputum of a Patient from Chennai, India, with Clinically Suspected Tuberculosis.

We announce the draft genome sequence of a multidrug-resistant Mycobacterium tuberculosis strain (CWCFVRF MDRTB 670) isolated from sputum from a patient with clinically suspected tuberculosis.

Indigenously produced polyhydroxyalkanoate based co-polymer as cellular supportive biomaterial.

The focus of this study was to evaluate the growth of the cells on a scaffold based on novel polyhydroxyalkanoate (PHA) (Polyhydroxy propionate copoly hydroxy ocatadecanoate copolymer), derived from a mutant strain of Pseudomonas sp. Naive PHA was also blended with several biodegradable polymeric materials (PEG, PLA, and MMT) to improve the scaffold properties. Protein adsorption study was done to evaluate the capability of scaffolds for cellular interaction. PHA:PEG blended scaffold showed better adsorption than others. 3T3 fibroblast cultures on various polymers were equally viable when compared with control culture except for the blend PHA:MMT by CCK 8 kit. MTT assay, performed with the continuous cultures HeLa, HEp-2, Vero, and McCoy on the polymer blends, supported the above finding. Among the blends PHA:PEG showed increased viability and was selected for further studies. Cell proliferation assay with colorimetric BrdU ELISA kit showed increase in cell proliferation over the matrix PHA:PEG than that of control. There were no observable morphological changes of continuous cells grown over matrix PHA:PEG when observed by phase contrast microscopy. HEp-2 cells were enclosed within the matrix when analyzed by SEM. The current study states that the scaffold prepared by using the indigenous PHA in combination with PEG supports cell growth better than the conventional plastic surface. PHA:PEG would be a promising material for tissue engineering.

First case series of emerging Rickettsial neonatal sepsis identified by polymerase chain reaction-based deoxyribonucleic acid sequencing.

PURPOSE: To detect and identify the aetiological agent in the peripheral blood from the cases of neonatal sepsis. MATERIALS AND METHODS: Four neonates from geographically different regions of South India presented with signs of neonatal sepsis and all the routine clinical and laboratory investigations were performed. Blood culture by Bac T Alert 3D was negative. To establish the aetiology, polymerase chain reaction (PCR) for eubacterial genome and subsequent amplification with Gram positive and Gram negative primers were performed followed by deoxyribonucleic acid (DNA) sequencing. RESULTS: PCR for the detection of eubacterial genome was positive in all the four neonates and further amplification with designed Gram positive and Gram negative primers revealed the presence of Gram negative bacteria. The amplicons were identified as Orientia tsutsugamushi in three neonates and Coxiella burnetti in the other neonate. Multalin analysis was done to further characterise the strain variation among the three strains. CONCLUSION: PCR-based DNA sequencing is a rapid and reliable diagnostic tool to identify the aetiological agents of neonatal sepsis. This is the first case series of emerging Rickettsial neonatal sepsis in India .

Diagnostic appraisal of simultaneous application of two nested PCRs targeting MPB64 gene and IS6110 region for rapid detection of M. tuberculosis genome in culture proven clinical specimens.

BACKGROUND: Early diagnosis of tuberculosis is critical for its effective management and prevention. Several gene amplification methods are used in the detection of tubercle bacilli from clinical specimens. MPB64 gene and IS6110 region have been identified as potential gene targets for the specific detection of Mycobacterium tuberculosis from direct clinical specimens. OBJECTIVE: The present study was conducted to evaluate the diagnostic utility of simultaneous application of two nested polymerase chain reaction (nPCRs) targeting MPB64 and IS6110 region for the detection of M. tuberculosis genome. MATERIALS AND METHODS: A total of 100 and 354 clinical specimens from the control group and clinically suspected tuberculosis patients, respectively, were included in the study. nPCRs targeting MPB64 and IS6110 region were performed. RESULTS AND CONCLUSION: All of the 100 clinical specimens from the control group were negative for both nPCRs. Out of the 354 clinical specimens, 339 were positive for both culture and nPCRs, 10 and 5 were positive for culture, and nPCR targeting IS6110 and MPB64 regions, respectively. To conclude, nPCRs targeting MPB64 and IS6110 region are reliable and specific targets when applied simultaneously on clinical specimens to attain 100% sensitivity for the detection of M. tuberculosis genome.

Clonal diversity of New Delhi metallobetalactamase-1 producing Enterobacteriaceae in a tertiary care centre.

PURPOSE: New Delhi metallobetalactamase-1 (NDM-1) production is a major mechanism of resistance to carbapenems among the Enterobacteriaceae and is a cause for concern in the field of microbial drug resistance. This study was performed to detect NDM-1 in Enterobacteriaceae and to determine the clonal relatedness of NDM-1 producing Escherichia coli and Klebsiella pneumoniae isolated from patients admitted in a tertiary care centre. MATERIALS AND METHODS: A total of 111 clinically significant Enterobacteriaceae isolates, resistant to cephalosporin subclass III were screened for carbapenemase production by the modified Hodge test. Minimum inhibitory concentration to imipenem and meropenem was determined and interpreted according to Clinical Laboratory Standards Institute 2011 criteria. Presence of bla NDM-1 was detected by polymerase chain reaction. To ascertain clonal relatedness, random amplification of polymorphic deoxyribonucleic acid (RAPD) was carried out for representative NDM-1 producers. RESULTS: bla NDM-1 was detected in 64 study isolates, of which 27 were susceptible to carbapenems. RAPD revealed a high degree of clonal diversity among NDM-1 producers except for a small clustering of isolates in the neonatal intensive care unit. CONCLUSION: There is extensive clonal diversity among the NDM-1 producing E. coli and K. pneumoniae. Hence, antibiotic selection pressure rather than horizontal transfer is probably an important operating factor for the emergence of NDM-1. This calls for increased vigilance, continuous surveillance and strict enforcement of antibiotic policy with restricted use of inducer drugs.

Development of a novel reverse transcriptase polymerase chain reaction to determine the Gram reaction and viability of bacteria in clinical specimens.

OBJECTIVE: To develop a novel RNA based assay to determine the Gram reaction and viability of bacteria in clinical specimens. MATERIALS AND METHODS: Reverse transcriptase PCR (RT-PCR) targeting 16SrRNA region was optimized using Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 by using two novel sets of primers. Sixty clinical specimens consisting of 31 intraocular specimens (19 vitreous fluids and 12 aqueous humor), 11 peripheral blood specimens and 18 other clinical specimens were subjected to standard microbiological culture and RT-PCR to determine the Gram reaction and viability of bacteria. The amplified products were subjected to DNA sequencing to identify the bacterium. RESULTS: The sensitivity of RT-PCR was 0.4fg and the primers amplified bacterial cDNA. RT-PCR detected the presence of bacteria in 60 clinical specimens indicating the presence of viable bacteria. Concordant results were obtained with both primer sets. Seventy five bacterium comprising 52 single (69.3%) and 23 mixed bacteria (30.6%), both Gram positive and Gram negative were detected. These results correlated with the bacterial identity by PCR based DNA sequencing. CONCLUSION: RT-PCR is a reliable tool to identify the presence of viable bacteria and to precisely determine Gram reaction.

Phenotypic and genotypic characteristics of drug resistance in Mycobacterium tuberculosis isolates from pediatric population of Chennai, India.

PURPOSE: Multidrug-resistant TB (MDR-TB) has been reported in almost all parts of the world. Childhood TB is accorded low priority by national TB control programs. Probable reasons include diagnostic difficulties, limited resources, misplaced faith in BCG and lack of data on treatment. Good data on the burden of all forms of TB among children in India are not available. OBJECTIVE: To study the drug sensitivity pattern of tuberculosis in children aged from 3 months to 18 years and the outcome of drug-resistant tuberculosis by BACTEC culture system and PCR-based DNA sequencing technique. MATERIALS AND METHODS: This is a retrospective study. One hundred and fifty-nine clinical specimens were processed for Ziehl-Neelsen stain, Mycobacterial culture by BACTEC method, phenotypic DST for first-line drugs for Mycobacterium tuberculosis (M. tuberculosis) isolates and PCR-based DNA sequencing was performed for the M. tuberculosis isolates targeting rpoB, katG, inhA, oxyR-ahpC, rpsL, rrs and pncA. RESULTS AND CONCLUSION: Out of the 159 Mycobacterial cultures performed during the study period, 17 clinical specimens (10.7%) were culture positive for M. tuberculosis. Among the 17 M. tuberculosis isolates, 2 were multidrug-resistant TB. PCR-based DNA sequencing revealed the presence of many novel mutations targeting katG, inhA, oxyR-ahpC and pncA and the most commonly reported mutation Ser531Leu in the rpoB gene. This study underlines the urgent need to take efforts to develop methods for rapid detection and drug susceptibility of tubercle bacilli in the pediatric population.

Isolation of a variant human adenovirus identified based on phylogenetic analysis during an outbreak of acute keratoconjunctivitis in Chennai.

BACKGROUND & OBJECTIVES: Though several viruses are responsible for conjunctivitis, but human adenovirus (HAdV) is by far the most common cause. Epidemic conjunctivitis causes morbidity and early detection of aetiological agent is essential in preventing spread of disease as some of serotypes of adenoviruses cause a severe form of conjunctivitis. This study was undertaken to identify the causative agent of conjunctivitis outbreak in Chennai in 2010. METHODS: Conjunctival samples collected from 17 patients with conjunctivitis were subjected to virological investigations. Culture and PCR for detection of adenovirus and enterovirus were carried out. PCR positive products were further subjected for DNA sequencing. The nucleotide sequences of the hexons of isolates were analyzed by comparison with all 51 human adenovirus strains. Phylogenetic tree was constructed using DAMBE software. RESULTS: Among 17 patients, seven were positive for adenovirus by PCR on the direct specimen, none was positive for enterovirus. Eleven of 30 conjunctival swabs showed cytopathic effect in HEp-2 cell line and were confirmed as HAdV by PCR. The DNA sequence data of the 11 isolates had equal percentage of homology with HAdV 6 and 2 on blast analysis. On phylogenetic analysis with GeneBank data of 51 adenovirus strains, 11 isolates from patients during the outbreak of conjunctivitis formed a separate clade indicating a new variant strain. INTERPRETATION & CONCLUSIONS: Based on phylogenetic analysis it was concluded that the recent conjunctivitis outbreak that occurred in Chennai was caused by a variant adenovirus strain.

Detection of Mycobacterium tuberculosis directly from sputum specimens & phenotypic drug resistance pattern of M. tuberculosis isolates from suspected tuberculosis patients in Chennai.

BACKGROUND & OBJECTIVES: mRNA is more rapidly destroyed in cells than rRNA or genomic DNA, an assay targeting bacterial mRNA would provide a better guide to mycobacterial viability than amplification tests directed at DNA or rRNA targets. This study was carried out to standardize reverse transcriptase PCR (RT-PCR) targeting 85B gene for the rapid detection of viable Mycobacterium tuberculosis from sputum specimens of suspected TB patients at Chennai, South India and to detect MDR-TB circulating in this population. METHODS: Sputum samples from clinically suspected tuberculosis patients (n=301) and 78 controls were included in the study. The sputum samples were collected in sterile diethyl pyrocarbonate (DEPC) treated containers and transported in ice to the laboratory within 2 h to prevent degradation of RNA. RT-PCR targeting 85B gene, mycobacterial culture and phenotypic drug susceptibility testing for the first line drugs streptomycin (S), isoniazid (H), rifampicin (R), ethambutol (E) and pyrazinamide (Z) were performed by BACTEC microMGIT culture system for all the sputum specimens. RESULTS: All the 78 controls were negative for culture and RT-PCR. Among the 301 sputum specimens from patients, 231 (76.8%) were RT-PCR positive and 70 (23.2%) were negative. There were 166 M. tuberculosis isolates, of which 11 (2.9%) were MDR-TB, 33 (8.7%) were polyresistant, 31 (8.2%) were monoresistant and 91 (30.2%) were sensitive to all five first line anti-tuberculous drugs by phenotypic drug susceptibility testing. Monoresistance was higher with Z [20 (20.8%)], followed by S [6 (3%)]. INTERPRETATION & CONCLUSIONS: RT-PCR targeting 85B gene of M. tuberculosis was a specific, rapid, reliable technique to detect the M. tuberculosis directly from sputum specimens. Our results showed that 2.9 per cent of M. tuberculosis isolates in the study population of Chennai were MDR.

Complication of salmonella bacteremia in a case of treated fungal endophthalmitis.

This is to report a case of bacteremia caused by Salmonella typhi in a treated unilateral fungal endogenous endophthalmitis in an 18-year-old male from one of the South Asian countries. Microbiological and molecular investigations were carried out on the eviscerated material and routine blood culture was carried out. Direct examination of eviscerated material revealed the presence of fungal filaments. However, Salmonella typhi was isolated from both specimens, which was confirmed by Polymerase chain reaction targeting the 16SrRNA gene, sequencing, and random amplification of polymorphic DNA showed that they belonged to the same clone. The presence of Salmonella bacteremia in a treated unilateral fungal endophthalmitis, among young adult patients is rare and systemic symptoms should be investigated.

Utility of QuantiFERON®-TB Gold test in diagnosis and management of suspected tubercular uveitis in India.

The tuberculin skin test, used to detect latent systemic tuberculosis (TB), has its limitations. The utility of interferon-gamma assays, found useful in the diagnosis of latent TB, is still unestablished in tubercular uveitis. We present the results of QuantiFERON(®)-TB Gold (QFT-G) test and its relevance in the diagnosis and management of suspected tubercular uveitis in India. All suspected tubercular uveitis patients seen at our uveitis clinic between October 2006 and June 2008 who underwent relevant blood investigations, chest X-rays, Mantoux tests and QFT-G tests were included. Clinical profile, systemic correlation and outcome with treatment were analysed. Fifty suspected tubercular uveitis patients underwent QFT-G testing. The age range of the patients was 6-55 years (mean 32.66 years). Seven patients presented with active and three with a past history of systemic TB. The QFT-G test was positive in 29 patients. Radiological findings of TB were seen in four patients with a positive QFT-G and one patient with a negative QFT-G test. In 11 patients both QFT-G and Mantoux tests were positive. Eighteen Mantoux-negative patients were QFT-G-positive. Significantly, no patient with a positive Mantoux had a negative QFT-G test. Of the 32 patients with posterior uveitis, 17 patients had serpiginous choroiditis, four patients had a choroidal granuloma, six patients had multifocal choroiditis, four patients had retinal vasculitis, and one patient had a subretinal abscess. All QFT-G-positive patients were treated with anti-tuberculosis therapy as well as systemic steroids with a favorable clinical outcome. Our study shows that the QFT-G test is very useful in the diagnosis and management of suspected ocular TB. It was found to be very sensitive in identifying latent TB patients who, upon treatment, had a significantly reduced frequency of recurrences. It was more sensitive than the Mantoux test and is not significantly affected by previous treatment with systemic steroids or immunosuppressives. A negative QFT-G test can also be used as an adjunct before initiation of systemic steroids or immunosuppressives in uveitic patients particularly in an endemic setting like India.