Contributions
Abstract: P421
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 12 Pathology
Background: Neuromyelitis optica (NMO) is an autoimmune-inflammatory CNS disease, mostly affecting spinal cord and optic nerve (ON). Disability in NMO can be severe and loss of visual function has major consequences for patients. Besides autoantibodies (abs) directed against aquaporin-4 (AQP4), abs targeting myelin-oligodendrocyte-glycoprotein (MOG) have been discovered. Knowledge about pathogenic effects of these abs on retina and ON is sparse.
Objective: To investigate binding characteristics of sera with AQP4- and MOG-abs to retina and ON as well as potential pathogenic effects on the visual pathway.
Methods: We incubated cryo-slices of murine retina and ON with sera of AQP4-ab (age 40.1 ± 10.8) or MOG-ab (age 31.5 ± 13.2) positive NMO patients. The sera's binding behavior was compared to sera from matched healthy controls. Serum staining was evaluated by three independent examiners in masked fashion using a non-parametric scoring system, ranging from 0 to 4 depending on signal intensity and specificity. To evaluate potential binding sites, we performed double stainings of sera and commercial antibodies against murine AQP4 or GFAP.
Results: 2/8 sera from AQP4-ab positive, and 3/8 sera from MOG-ab positive patients depicted distinct staining patterns in the retina or ON. In the retina, quantification did not show significant differences between sera containing AQP4-abs (1.86±0.54; p=0.85) or MOG-abs (0.91±0.45; p=0.52) in comparison to control sera (1.55±0.36). In the ON, again no significant differences were found, however with a tendency of AQP4-ab-positive sera to show a stronger signal (2.11±0.52; p=0.25) than MOG-ab-positive sera (0.96±0.38; p=0.85) in comparison to controls (1.23±0.22). One serum from three distinct MOG-ab positive sera exclusively stained ON while the other two only stained retina. Two AQP4-ab positive sera displayed a specific signal against retina and ON, one with co-localization with AQP4- and one with GFAP-staining.
Conclusion: Sera from NMO patients with AQP4- or MOG-abs show distinct and within each group different binding patterns against murine retina and ON, indicating that various epitopes are targeted. Co-staining of NMO sera with AQP4 but also GFAP was shown previously. This points towards existence of anti-GFAP-abs in NMO. Their role in the disease still needs to be investigated. In further studies, we will examine the mechanisms of ab-mediated damage to retina and ON.
Funding: Hertie Foundation; FoRUM Program (Ruhr-University Bochum)
Disclosure:
Florian Graz: nothing to disclose
Sabrina Reinehr: nothing to disclose
Steffen Haupeltshofer: nothing to disclose
Ralf Gold: R. G. serves on scientific advisory boards for Teva Pharmaceutical Industries Ltd., Biogen Idec, Bayer Schering Pharma, and Novartis; has received speaker honoraria from Biogen Idec, Teva Pharmaceutical Industries Ltd., Bayer Schering Pharma, and Novartis; serves as editor for Therapeutic Advances in Neurological Diseases and on the editorial boards of Experimental Neurology and the Journal of Neuroimmunology; and receives research support from Teva Pharmaceutical Industries Ltd., Biogen Idec, Bayer Schering Pharma, Genzyme, Merck Serono, and Novartis, none related to this manuscript
Simon Faissner: S. F. received travel grants from Biogen and Genzyme, not related to the content of this manuscript.
Stephanie C Joachim: nothing to disclose
Ingo Kleiter: IK received honoraria for consultancy or speaking and travel reimbursement from Bayer Healthcare, Chugai, Merck, Roche, and Shire, and grant support from Affectis, Biogen, Chugai and Diamed, all not related to this manuscript
Abstract: P421
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 12 Pathology
Background: Neuromyelitis optica (NMO) is an autoimmune-inflammatory CNS disease, mostly affecting spinal cord and optic nerve (ON). Disability in NMO can be severe and loss of visual function has major consequences for patients. Besides autoantibodies (abs) directed against aquaporin-4 (AQP4), abs targeting myelin-oligodendrocyte-glycoprotein (MOG) have been discovered. Knowledge about pathogenic effects of these abs on retina and ON is sparse.
Objective: To investigate binding characteristics of sera with AQP4- and MOG-abs to retina and ON as well as potential pathogenic effects on the visual pathway.
Methods: We incubated cryo-slices of murine retina and ON with sera of AQP4-ab (age 40.1 ± 10.8) or MOG-ab (age 31.5 ± 13.2) positive NMO patients. The sera's binding behavior was compared to sera from matched healthy controls. Serum staining was evaluated by three independent examiners in masked fashion using a non-parametric scoring system, ranging from 0 to 4 depending on signal intensity and specificity. To evaluate potential binding sites, we performed double stainings of sera and commercial antibodies against murine AQP4 or GFAP.
Results: 2/8 sera from AQP4-ab positive, and 3/8 sera from MOG-ab positive patients depicted distinct staining patterns in the retina or ON. In the retina, quantification did not show significant differences between sera containing AQP4-abs (1.86±0.54; p=0.85) or MOG-abs (0.91±0.45; p=0.52) in comparison to control sera (1.55±0.36). In the ON, again no significant differences were found, however with a tendency of AQP4-ab-positive sera to show a stronger signal (2.11±0.52; p=0.25) than MOG-ab-positive sera (0.96±0.38; p=0.85) in comparison to controls (1.23±0.22). One serum from three distinct MOG-ab positive sera exclusively stained ON while the other two only stained retina. Two AQP4-ab positive sera displayed a specific signal against retina and ON, one with co-localization with AQP4- and one with GFAP-staining.
Conclusion: Sera from NMO patients with AQP4- or MOG-abs show distinct and within each group different binding patterns against murine retina and ON, indicating that various epitopes are targeted. Co-staining of NMO sera with AQP4 but also GFAP was shown previously. This points towards existence of anti-GFAP-abs in NMO. Their role in the disease still needs to be investigated. In further studies, we will examine the mechanisms of ab-mediated damage to retina and ON.
Funding: Hertie Foundation; FoRUM Program (Ruhr-University Bochum)
Disclosure:
Florian Graz: nothing to disclose
Sabrina Reinehr: nothing to disclose
Steffen Haupeltshofer: nothing to disclose
Ralf Gold: R. G. serves on scientific advisory boards for Teva Pharmaceutical Industries Ltd., Biogen Idec, Bayer Schering Pharma, and Novartis; has received speaker honoraria from Biogen Idec, Teva Pharmaceutical Industries Ltd., Bayer Schering Pharma, and Novartis; serves as editor for Therapeutic Advances in Neurological Diseases and on the editorial boards of Experimental Neurology and the Journal of Neuroimmunology; and receives research support from Teva Pharmaceutical Industries Ltd., Biogen Idec, Bayer Schering Pharma, Genzyme, Merck Serono, and Novartis, none related to this manuscript
Simon Faissner: S. F. received travel grants from Biogen and Genzyme, not related to the content of this manuscript.
Stephanie C Joachim: nothing to disclose
Ingo Kleiter: IK received honoraria for consultancy or speaking and travel reimbursement from Bayer Healthcare, Chugai, Merck, Roche, and Shire, and grant support from Affectis, Biogen, Chugai and Diamed, all not related to this manuscript