Role of Regulatory T Cells in Tubercular Uveitis.

PURPOSE: To study the role of regulatory T cells (Tregs) in patients with tubercular uveitis. METHODS: Frequencies of peripheral Tregs, Th1, Th17 cells, and intracellular cytokines were determined in 17 tubercular uveitis patients and 18 disease controls. Function of Tregs, Th1, and Th17 cells was assessed in vitro. Simultaneously, ocular levels of IFN-γ, IL-17A, IL-4, and IL-10 were also measured. RESULTS: Frequencies of peripheral Tregs in tubercular uveitis subjects were significantly lower compared with disease controls. Furthermore, expression of TGF-ß and IL-2Rα, but not CTLA4, was reduced in Tregs of the tubercular uveitis group. The tubercular uveitis group demonstrated heightened Th1, Th17 responses following in vitro stimulation with phorbol myristate acetate (PMA)/ionomycin. Interestingly, Treg suppression assay did not show a significant difference between the two groups. Ocular levels of IFN-γ, IL-17A, and IL-10 were also elevated in tubercular uveitis group. CONCLUSIONS: Low Treg frequency and hyporesponsive function contribute to proinflammatory responses manifesting at ocular level in tubercular uveitis.

Safety and Outcome of Microincision Vitreous Surgery in Uveitis.

PURPOSE: To report the outcome of microincision vitreous surgery (MIVS) in uveitis. METHODS: In total, 103 patients (106 eyes) underwent diagnostic MIVS between March 2012 and April 2015. Postoperative evaluation included vitreous haze grading from clinical/electronic records, best-corrected visual acuity (BCVA), and complications. RESULTS: Mean age was 36.8 ± 13.9 years (range: 8-80 years). Mean follow-up after MIVS was 12.2 ± 7.2 months (median 12 months). Mean vitreous haze grading was 2.39 ± 0.98 (preoperatively), 0.36 ± 0.73 postoperatively (1 week), and 0.02 ± 0.2 at 1 month (p < 0.001). Mean BCVA was 1.5 ± 1.0 logMAR preoperatively and 0.72 ± 0.68 logMAR at 1 month (p = 0.000). Postoperative complications included cataract (14.6%), rise in intraocular pressure (13.2%), vitreous hemorrhage (4.7%), hypotony (3.2%), retinal detachment (2.8%), epiretinal membrane (2.8%), and worsening of inflammation (0.9%). CONCLUSIONS: MIVS is safe and may have a therapeutic role in uveitis.

Detection of Mycobacterium tuberculosis genome in vitreous fluid of eyes with multifocal serpiginoid choroiditis.

PURPOSE: To compare 3 different molecular techniques to detect the Mycobacterium tuberculosis genome in vitreous fluid of eyes with multifocal serpiginoid choroiditis (MSC). DESIGN: Prospective, interventional case series. PARTICIPANTS: Eleven patients (11 eyes) with active MSC in at least 1 eye underwent diagnostic pars plana vitrectomy (PPV) between October 2012 and December 2013. METHODS: Vitreous fluid samples were subjected to multitargeted polymerase chain reaction (PCR) for a M. tuberculosis assay, the Gene Xpert MTB/RIF assay (Cepheid, Sunnyvale, CA), and a line probe assay (GenoType MTBDRplus; Hain Lifescience, GmbH, Nehren, Germany). The samples with positive results were subjected to rpoB gene sequencing to demonstrate rifampicin resistance. The clinical details, digital fundus imaging, and treatment details and outcomes also were noted. MAIN OUTCOME MEASURES: Detection of the M. tuberculosis genome and rifampicin resistance in the vitreous samples. RESULTS: Of the 11 eyes subjected to PPV, the multitargeted PCR results for tuberculosis were positive for 10 eyes, the MTBDRplus assay results were positive in 6 eyes, and the Gene Xpert MTB/RIF assay results were positive in 4 eyes. Rifampicin resistance was detected in 3 eyes by rpoB gene sequencing, in 3 eyes by the MTBDRplus assay, and in 1 eye by the Gene Xpert MTB/RIF assay. CONCLUSIONS: We detected the M. tuberculosis genome in the vitreous fluid of eyes with MSC using 3 different molecular techniques. Rifampicin resistance was detected for the first time in eyes with MSC.

MHC class I-presented T cell epitopes identified by immunoproteomics analysis are targets for a cross reactive influenza-specific T cell response.

Influenza virus infection and the resulting complications are a significant global public health problem. Improving humoral immunity to influenza is the target of current conventional influenza vaccines, however, these are generally not cross-protective. On the contrary, cell-mediated immunity generated by primary influenza infection provides substantial protection against serologically distinct viruses due to recognition of cross-reactive T cell epitopes, often from internal viral proteins conserved between viral subtypes. Efforts are underway to develop a universal flu vaccine that would stimulate both the humoral and cellular immune responses leading to long-lived memory. Such a universal vaccine should target conserved influenza virus antibody and T cell epitopes that do not vary from strain to strain. In the last decade, immunoproteomics, or the direct identification of HLA class I presented epitopes, has emerged as an alternative to the motif prediction method for the identification of T cell epitopes. In this study, we used this method to uncover several cross-specific MHC class I specific T cell epitopes naturally presented by influenza A-infected cells. These conserved T cell epitopes, when combined with a cross-reactive antibody epitope from the ectodomain of influenza M2, generate cross-strain specific cell mediated and humoral immunity. Overall, we have demonstrated that conserved epitope-specific CTLs could recognize multiple influenza strain infected target cells and, when combined with a universal antibody epitope, could generate virus specific humoral and T cell responses, a step toward a universal vaccine concept. These epitopes also have potential as new tools to characterize T cell immunity in influenza infection, and may serve as part of a universal vaccine candidate complementary to current vaccines.

Conserved MHC class I-presented dengue virus epitopes identified by immunoproteomics analysis are targets for cross-serotype reactive T-cell response.

Dengue fever and dengue hemorrhagic fever are significant global public health problems, and understanding the overall immune response to infection will contribute to appropriate management of the disease and its potentially severe complications. Live attenuated and subunit vaccine candidates, which are under clinical evaluation, induce primarily an antibody response to the virus and minimal cross-reactive T-cell responses. Currently, there are no available tools to assess protective T-cell responses during infection or after vaccination. In this study, we utilize an immunoproteomics process to uncover novel HLA-A2-specific epitopes derived from dengue virus (DV)-infected cells. These epitopes are conserved, and we report that epitope-specific cytotoxic lymphocytes (CTLs) are cross-reactive against all 4 DV serotypes. These epitopes have potential as new informational and diagnostic tools to characterize T-cell immunity in DV infection and may serve as part of a universal vaccine candidate complementary to current vaccines in trial.

MHC class I-presented lung cancer-associated tumor antigens identified by immunoproteomics analysis are targets for cancer-specific T cell response.

The development of potent cancer vaccines for common malignancies such as lung cancer requires identification of suitable target antigens. We hypothesized that peptide epitopes naturally presented by MHC class I molecules on the surface of cancer cells would be the most relevant targets. We used LC/MS/MS analysis and identified 68 MHC class I-presented peptides from lung cancer cells. Using the criteria of strong consensus for HLA-A2 binding and relevance of the source proteins to malignant phenotype, we selected 8 peptides for functional characterization. These peptides, with a range of binding affinities, were confirmed to stabilize HLA-A2 molecules and were used to activate peptide-specific CTLs that efficiently recognized lung tumor cells. No correlation between the transcript levels of the source proteins and the extent of peptide-specific T cell recognition of lung cancer cells was observed. Furthermore, the peptide specific CTLs failed to recognize HLA-A2+ normal lung cells despite expression of the mRNA encoding the source proteins from which the peptides were derived. We conclude that MHC class I associated peptide epitopes are a more relevant source of authentic tumor antigens than over-expressed proteins and the identified peptides may be used as antigens for therapeutic vaccine strategies to treat lung cancer.

HLA typing in Vogt-Koyanagi-Harada syndrome in North Indian patients.

PURPOSE: To report the HLA profile of VKH patients from India. METHOD: Forty-one patients and 50 controls were studied. Phenotyping using a lymphocytotoxicity assay was done for HLA-A and -B. DNA-based sequence-specific low resolution typing was done for HLA-DR and -DQ loci. RESULTS: HLA-A9 was over-represented in the patient population (p = 0.01), whereas HLA-A11 (p = 0.03) and HLA-DRB1*13 (p = 0.007) were found to be underrepresented. The frequency of HLA-DRB1*04 was 14.6% and 10% in the patient population and controls, respectively. The HLA-DQ frequencies did not differ significantly between patients and controls. CONCLUSION: Unlike that reported in most populations, we did not find a significant association between HLA-DRB1*04 and our patient population.