CRB1-associated retinal dystrophy patients have expanded Lewis glycoantigen-positive T cells

PURPOSE. Eye inflammation may occur in patients with inherited retinal dystrophies (IRDs) and is seen frequently in IRDs associated with mutations in the CRB1 gene. The purpose of this study was to determine the types of inflammatory cells involved in IRDs, by deep profiling the composition of peripheral blood mononuclear cells of patients with a CRB1-associated IRD.METHODS. This study included 33 patients with an IRD with confirmed CRB1 mutations and 32 healthy controls. A 43-parameter flow cytometry analysis was performed on peripheral blood mononuclear cells isolated from venous blood. FlowSOM and manual Boolean combination gating were used to identify and quantify immune cell subsets.RESULTS. Comparing patients with controls revealed a significant increase in patients in the abundance of circulating CD4+ T cells and CD8+ T cells that express sialyl Lewis X antigen. Furthermore, we detected a decrease in plasmacytoid dendritic cells and an IgA+CD24+CD38+ transitional B-cell subset in patients with an IRD. CONCLUSIONS. Patients with a CRB1-associated IRD show marked changes in blood leukocyte composition, affecting lymphocyte and dendritic cell populations. These results implicate inflammatory pathways in the disease manifestations of IRDs.Ophthalmic researc

ERAP2 increases the abundance of a peptide submotif highly selective for the Birdshot Uveitis-associated HLA-A29

Birdshot Uveitis (BU) is a blinding inflammatory eye condition that only affects HLA-A29-positive individuals. Genetic association studies linked ERAP2 with BU, an aminopeptidase which trims peptides before their presentation by HLA class I at the cell surface, which suggests that ERAP2-dependent peptide presentation by HLA-A29 drives the pathogenesis of BU. However, it remains poorly understood whether the effects of ERAP2 on the HLA-A29 peptidome are distinct from its effect on other HLA allotypes. To address this, we focused on the effects of ERAP2 on the immunopeptidome in patient-derived antigen presenting cells. Using complementary HLA-A29-based and pan-class I immunopurifications, isotope-labeled naturally processed and presented HLA-bound peptides were sequenced by mass spectrometry. We show that the effects of ERAP2 on the N-terminus of ligands of HLA-A29 are shared across endogenous HLA allotypes, but discover and replicate that one peptide motif generated in the presence of ERAP2 is specifically bound by HLA-A29. This motif can be found in the amino acid sequence of putative autoantigens. We further show evidence for internal sequence specificity for ERAP2 imprinted in the immunopeptidome. These results reveal that ERAP2 can generate an HLA-A29-specific antigen repertoire, which supports that antigen presentation is a key disease pathway in BU.Proteomic

Novel insights into the pathogenesis of Birdshot chorioretinopathy

Birdshot chorioretinopathy (BSCR) is a rare and poorly understood form of autoimmune uveitis that can lead to severe visual impairment. Intriguingly, >95% of cases carry the HLA-A29 allele and defines the strongest documented HLA association for a human disease. To better understand the underlying pathophysiology we investigated the ocular microenvironment, the role of T cells, and the identification of additional genetic markers. Patients showed elevated intraocular levels of pro-inflammatory cytokines TNF-alpha, IL-1-beta, IL-6, IL-2 and particularly IL-17. Interestingly, IL-17-specific cytokine responses and the induction of T helper 17 cells were observed in peripheral blood mononuclear cells of patients stimulated with human ocular antigens.Also, intraocular T cells (derived from vitreous fluid during pars plana vitrectomy) were shown to be directed against human retina and choroid extracts. This substantiates the emerging concept of autoreactive T cells that specifically target the eye in the pathophysiology of BSCR. Finally, we present the first genome-wide association study of this extremely rare eye disease. We show that the MHC association is conferred by HLA-A*29:02 with unusually large effect size. More importantly, we identify an ERAP2 risk allele that increases mRNA and protein expression levels of ERAP2. The dual association between a specific HLA-A allele and ERAP2 implicates a role for peptide processing and antigen presentation in the disease mechanism

Assessing classroom climate in special education: A validation study of the Special Education Classroom Climate Inventory

This study examined the internal structure, convergent validity, and reliability of the student self-report Special Education Classroom Climate Inventory (SECCI) in a sample of 325 students attending special education classes in six (semi) secure residential settings and in two youth prisons in the Netherlands. Both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) provided evidence of a theoretically based four-factor model—with Teacher Support, Positive Student Affiliation, Negative Student Interactions, and Unstructured Classroom Environment as dimensions—showing an adequate fit to the data, providing preliminary support for validity of the SECCI. Limited evidence for convergent validity was found in significant but small associations between classroom climate and academic self-concept. Ordinal Cronbach’s alpha reliability coefficients were good for all factors. The SECCI might be used to assess and subsequently target (problematic) classroom climate in schools for special education for students in (secure) residential youth care and youth prisons, although further development of the SECCI and replication of our study results seem necessary

The impact of classroom climate on students' perception of social exclusion in secondary special education

The present study examines the relation between classroom climate in schools for secondary special education and students' perceived social exclusion. A total of 401 Dutch adolescents (70.3% males) with conduct problems, attending schools for special education, filled out questionnaires on classroom climate, problems in social information processing, externalizing behavior and perceived social exclusion. Results showed that a positive classroom climate was associated with a reduction of students' externalizing behavior problems and perceived social exclusion, which was associated with improvements in social information processing. However, these relations were only found at the within group level of analysis (between students) and not at the between group level (between classes); thus contextual (class level) effects could not be demonstrated. It can be carefully stated that a positive classroom climate in secondary special education may protect against perceived social exclusion. Future research is required to examine whether our findings can be replicated in other schools for secondary special education or can be generalized to secondary education in general

Retina-arrestin specific CD8+T cells are not implicated in HLA-A29-positive birdshot chorioretinitis

Background: HLA-A29-positive birdshot chorioretinitis (BCR) is an inflammatory eye disorder that is generally assumed to be caused by an autoimmune response to HLA-A29-presented peptides from retinal arrestin (SAG), yet the epitopes recognized by CD8+ T cells from patients remain to be identified. Objectives: The identification of natural ligands of SAG presented by HLA-A29. To quantify CD8+ T cells reactive to antigenic SAG peptides presented by HLA-A29 in patients and controls. Methods: We performed mass-spectrometry based immunopeptidomics of HLA-A29 of antigen-presenting cell lines from patients engineered to express SAG. MHC-I Dextramer technology was utilised to determine expansion of antigen-specific CD8+ T cells reactive to SAG peptides in complex with HLA-A29 in a cohort of BCR patients, HLA-A29-positive controls, and HLA-A29-negative controls. Results: We report on the naturally presented antigenic SAG peptides identified by sequencing the HLA-A29 immunopeptidome of antigen-presenting cells of patients. We show that the N-terminally extended SAG peptide precursors can be trimmed in vitro by the antigen-processing aminopeptidases ERAP1 and ERAP2. Unex-pectedly, no enhanced antigen engagement by CD8+ T cells upon stimulation with SAG peptides was observed in patients or HLA-A29-positive controls. Multiplexed HLA-A29-peptide dextramer profiling of a case-control cohort revealed that CD8+ T cells specific for these SAG peptides were neither detectable in peripheral blood nor in eye biopsies of patients. Conclusions: Collectively, these findings demonstrate that SAG is not a CD8+ T cell autoantigen and sharply contrast the paradigm in the pathogenesis of BCR. Therefore, the mechanism by which HLA-A29 is associated with BCR does not involve SAG.</p

ERAP2 Increases the Abundance of a Peptide Submotif Highly Selective for the Birdshot Uveitis-Associated HLA-A29

Contains fulltext : 231666.pdf (publisher's version ) (Open Access)Birdshot Uveitis (BU) is a blinding inflammatory eye condition that only affects HLA-A29-positive individuals. Genetic association studies linked ERAP2 with BU, an aminopeptidase which trims peptides before their presentation by HLA class I at the cell surface, which suggests that ERAP2-dependent peptide presentation by HLA-A29 drives the pathogenesis of BU. However, it remains poorly understood whether the effects of ERAP2 on the HLA-A29 peptidome are distinct from its effect on other HLA allotypes. To address this, we focused on the effects of ERAP2 on the immunopeptidome in patient-derived antigen presenting cells. Using complementary HLA-A29-based and pan-class I immunopurifications, isotope-labeled naturally processed and presented HLA-bound peptides were sequenced by mass spectrometry. We show that the effects of ERAP2 on the N-terminus of ligands of HLA-A29 are shared across endogenous HLA allotypes, but discover and replicate that one peptide motif generated in the presence of ERAP2 is specifically bound by HLA-A29. This motif can be found in the amino acid sequence of putative autoantigens. We further show evidence for internal sequence specificity for ERAP2 imprinted in the immunopeptidome. These results reveal that ERAP2 can generate an HLA-A29-specific antigen repertoire, which supports that antigen presentation is a key disease pathway in BU

A pan‐inflammatory microRNA‐cluster is associated with orbital non‐Hodgkin lymphoma and idiopathic orbital inflammation

Ophthalmic researc

A pan-inflammatory microRNA-cluster is associated with orbital non-Hodgkin lymphoma and idiopathic orbital inflammation

Ophthalmic researc