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60th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN)

German Society for Neuropathology and Neuroanatomy

26. - 28.08.2015, Berlin

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C5b-9 upregulation on endomysial capillaries in non-dermatomyositis cases

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  • corresponding author presenting/speaker Anne Braczynski - Uniklinik RWTH Aachen, Institute of Neuropathology, Aachen, United Kingdom
  • Patrick N. Harter - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany
  • Pia S. Zeiner - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany
  • Ulrich Drott - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany
  • Dominique-Suzanne Tews - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany
  • Corinna Preusse - Charité, Department of Neuropathology, Berlin, Germany
  • Maika Dunst - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany; Charité, Department of Neuropathology, Berlin, Germany
  • Hans-Hilmar Goebel - Charité, Department of Neuropathology, Berlin, Germany
  • Joachim Weis - Uniklinik RWTH Aachen, Institute of Neuropathology, Aachen, Germany
  • Werner Stenzel - Charité, Department of Neuropathology, Berlin, Germany
  • Michel Mittelbronn - University of Frankfurt am Main, Edinger Institute, Institute of Neurology, Frankfurt, Germany

Deutsche Gesellschaft für Neuropathologie und Neuroanatomie. 60th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN). Berlin, 26.-28.08.2015. Düsseldorf: German Medical Science GMS Publishing House; 2015. Doc15dgnnP42

doi: 10.3205/15dgnn66, urn:nbn:de:0183-15dgnn660

Published: August 25, 2015

© 2015 Braczynski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

Text

Question: Upregulation of the terminal membrane attack complex (MAC) C5b-9 on endomysial capillaries is generally regarded as major diagnostic hallmark of dermatomyositis (DM). Although the underlying pathophysiology is not entirely understood, C5b-9 upregulation seems to lead to microinfarctions and damage of the vascular network. We report on a case series of 19 patients presenting with a C5b-9 accumulation on endomysial capillaries in the absence of clinical or neuropathological evidence for DM and critically evaluate this marker.

Methods: We compared the C5b-9 staining pattern of 19 non-DM patients with 12 DM and 8 control patients. To decipher potential differences in the C5b-9 distribution pattern between DM and non-DM cases, we additionally assessed the extent of endomysial capillary C5b-9 deposits related to the capillary density and extent of myofiber necrosis by immunohistochemistry. Clinical data was added via a telephone follow-up.

Results: Our results show that similar numbers of C5b-9-positive myofibers were present in both DM and non-DM C5b-9+ cases. However, the distribution pattern significantly differed as DM cases showed significantly more perifascicular C5b-9 deposits as compared to non-DM cases, the latter presenting with stronger C5b-9 expression on endomysial capillaries in a diffuse pattern. Of note, the total capillary density did not significantly differ between normal control tissues, DM and non-DM C5b-9+ cases but DM patients displayed significantly more C5b-9+ necrotic fibers as compared to non-DM C5b-9+ and control cases.

Conclusion: In summary, our results show that endomysial capillary C5b-9 deposits are also present in a large variety of non-DM cases with a tendency to autoimmune diseases. However the distribution pattern significantly differed from DM cases. In conclusion, C5b-9+ deposits should only be relied on as an immunohistochemical criterion for the diagnosis of DM if the C5b-9 distribution pattern is taken into consideration.