Contributions
Abstract: 152
Type: Free Communications
Abstract Category: Pathology and pathogenesis of MS - Immunology
Introduction: CD4+ T-cells are key players in the pathogenesis of autoimmune diseases, which initiate central nervous system (CNS) inflammation and blood brain barrier disruption. Mutually exclusive autoantibodies targeting the astrocytic water channel aquaporin-4 (AQP4-ab) or the oligodendroglial myelin-oligodendrocyte-glycoprotein (MOG-ab) are associated with a broad spectrum of human CNS demyelinating diseases including neuromyelitis optica spectrum disorders (NMOSD). In this regard, a significant proportion of the AQP4-ab seronegative NMOSD patients harbour MOG-ab indicating a possible role of MOG to NMO pathogenesis or vice versa an involvement of AQP4-specific T-cells in MOG-ab seropositive NMOSD patients.
Methods: Peripheral blood T-cells from nine AQP4-ab+, eight MOG-ab+, one double-seronegative NMOSD patients and eight healthy controls (HC) were examined for recognition of selected single AQP4 and MOG peptides using the carboxyfluorescein succinimidyl ester (CFSE)-proliferation assay. The functional phenotype of proliferated T-cells was determined by evaluating cytokine production (interferon(IFN)-ɣ, interleukin(IL)-17A) using a flow cytometry-based intracellular staining (ICS) and cytokine secretion in cell culture supernatants (granulocyte-macrophage colony-stimulating factor (GM-CSF), IFN-ɣ, IL-4, IL-6, IL-17A) using ELISA. In addition, a human leucocyte antigen (HLA)-DR and -DQ typing of all participants was performed using the polymerase chain reaction with sequence-specific primer technique (PCR-SSP).
Results: Significant CD4+ T-cell proliferation in response to AQP4, but not to MOG peptides, was found in 8/9 (89%) AQP4-ab+ and in 5/6 (83%) AQP-ab seronegative NMOSD patients but in no HC (0/8). ICS revealed strong IFN-ɣ production indicative of a pro-inflammatory Th1 phenotype. Cytokine secretion was either not detectable (IL-4, IL-17A) or not specific (GM-CSF, IFN-ɣ, IL-6). HLA typing showed that immunodominance of AQP4 peptides was restricted to DRB1*01 and that DRB5 had a protective effect.
Conclusions: These results not only highlight AQP4 as the main target of T-cells and antibodies in AQP4-ab+ NMO but even more strikingly show that AQP4-specific CD4+ T-cells are also present in MOG-ab+ NMOSD, which could explain clinical features of these patients and may justify the inclusion of MOG-ab+ patients under the umbrella of NMOSD. Our results could form the basis for the development of new individualised immune-tolerance therapies.
Disclosure: Livia Hofer was supported by a research grant from the Austrian Multiple Sclerosis Research Society (ÖMSFG).
Melanie Ramberger was supported by research grants from the Austrian Science Funds (FWF graduate program W1206 SPIN) and the Tyrolean Science Fund (TWF; GZ: UNI-0404/1235).
Anna Sophie Pescoller: nothing to disclose.
Viktoria Gredler was supported by a research grant from the Tyrolean Science Fund (TWF; GZ: UNI-0404/1235).
Kevin Rostasy is an external advisor for the PARADIGMS study and receives Merck-speakers' honoraria.
Andreas Lutterotti was supported by research grants from the University of Zurich (Clinical Research Priority Program MS), the Swiss MS Society and Wyss Zurich.
Mireia Sospedra Ramos: nothing to disclose.
Roland Martin: nothing to disclose.
Thomas Berger was supported by research grants from the Austrian Multiple Sclerosis Research Society (ÖMSFG) and the Austrian Federal Ministry of Science, Research and Education.
Markus Reindl was supported by research grants from the Austrian Multiple Sclerosis Research Society (ÖMSFG), the Austrian Science Funds (FWF graduate program W1206 SPIN), the Tyrolean Science Fund (TWF), the Austrian Science Promotion Agency (FFG) and the Austrian Federal Ministry of Science, Research and Education.
The University Hospital and Medical University of Innsbruck (Austria; M.R. and T.B.) receives payments for antibody assays (MOG, AQP4, and other autoantibodies) and for MOG and AQP4 antibody validation experiments organized by Euroimmun (Lübeck, Germany).
Abstract: 152
Type: Free Communications
Abstract Category: Pathology and pathogenesis of MS - Immunology
Introduction: CD4+ T-cells are key players in the pathogenesis of autoimmune diseases, which initiate central nervous system (CNS) inflammation and blood brain barrier disruption. Mutually exclusive autoantibodies targeting the astrocytic water channel aquaporin-4 (AQP4-ab) or the oligodendroglial myelin-oligodendrocyte-glycoprotein (MOG-ab) are associated with a broad spectrum of human CNS demyelinating diseases including neuromyelitis optica spectrum disorders (NMOSD). In this regard, a significant proportion of the AQP4-ab seronegative NMOSD patients harbour MOG-ab indicating a possible role of MOG to NMO pathogenesis or vice versa an involvement of AQP4-specific T-cells in MOG-ab seropositive NMOSD patients.
Methods: Peripheral blood T-cells from nine AQP4-ab+, eight MOG-ab+, one double-seronegative NMOSD patients and eight healthy controls (HC) were examined for recognition of selected single AQP4 and MOG peptides using the carboxyfluorescein succinimidyl ester (CFSE)-proliferation assay. The functional phenotype of proliferated T-cells was determined by evaluating cytokine production (interferon(IFN)-ɣ, interleukin(IL)-17A) using a flow cytometry-based intracellular staining (ICS) and cytokine secretion in cell culture supernatants (granulocyte-macrophage colony-stimulating factor (GM-CSF), IFN-ɣ, IL-4, IL-6, IL-17A) using ELISA. In addition, a human leucocyte antigen (HLA)-DR and -DQ typing of all participants was performed using the polymerase chain reaction with sequence-specific primer technique (PCR-SSP).
Results: Significant CD4+ T-cell proliferation in response to AQP4, but not to MOG peptides, was found in 8/9 (89%) AQP4-ab+ and in 5/6 (83%) AQP-ab seronegative NMOSD patients but in no HC (0/8). ICS revealed strong IFN-ɣ production indicative of a pro-inflammatory Th1 phenotype. Cytokine secretion was either not detectable (IL-4, IL-17A) or not specific (GM-CSF, IFN-ɣ, IL-6). HLA typing showed that immunodominance of AQP4 peptides was restricted to DRB1*01 and that DRB5 had a protective effect.
Conclusions: These results not only highlight AQP4 as the main target of T-cells and antibodies in AQP4-ab+ NMO but even more strikingly show that AQP4-specific CD4+ T-cells are also present in MOG-ab+ NMOSD, which could explain clinical features of these patients and may justify the inclusion of MOG-ab+ patients under the umbrella of NMOSD. Our results could form the basis for the development of new individualised immune-tolerance therapies.
Disclosure: Livia Hofer was supported by a research grant from the Austrian Multiple Sclerosis Research Society (ÖMSFG).
Melanie Ramberger was supported by research grants from the Austrian Science Funds (FWF graduate program W1206 SPIN) and the Tyrolean Science Fund (TWF; GZ: UNI-0404/1235).
Anna Sophie Pescoller: nothing to disclose.
Viktoria Gredler was supported by a research grant from the Tyrolean Science Fund (TWF; GZ: UNI-0404/1235).
Kevin Rostasy is an external advisor for the PARADIGMS study and receives Merck-speakers' honoraria.
Andreas Lutterotti was supported by research grants from the University of Zurich (Clinical Research Priority Program MS), the Swiss MS Society and Wyss Zurich.
Mireia Sospedra Ramos: nothing to disclose.
Roland Martin: nothing to disclose.
Thomas Berger was supported by research grants from the Austrian Multiple Sclerosis Research Society (ÖMSFG) and the Austrian Federal Ministry of Science, Research and Education.
Markus Reindl was supported by research grants from the Austrian Multiple Sclerosis Research Society (ÖMSFG), the Austrian Science Funds (FWF graduate program W1206 SPIN), the Tyrolean Science Fund (TWF), the Austrian Science Promotion Agency (FFG) and the Austrian Federal Ministry of Science, Research and Education.
The University Hospital and Medical University of Innsbruck (Austria; M.R. and T.B.) receives payments for antibody assays (MOG, AQP4, and other autoantibodies) and for MOG and AQP4 antibody validation experiments organized by Euroimmun (Lübeck, Germany).