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

Anne K. Braczynski, Patrick N. Harter, Pia S. Zeiner, Ulrich Drott, Dominique Suzanne Tews, Corinna Preusse, Cornelia Penski, Maika Dunst, Joachim Weis, Werner Stenzel, Michel Mittelbronn*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)


Deposits of the terminal-membrane-attack-complex (MAC) C5b-9 on perfascicular endomysial capillaries are generally regarded as diagnostic hallmark of dermatomyositis (DM). Although the pathophysiology is not clear, C5b-9 deposits on capillaries seem to be associated with microinfarctions and vascular damage. Here, we report on a series of 19 patients presenting with C5b-9 accumulation on endomysial capillaries in the absence of features for DM. To decipher differences in the capillary C5b-9 accumulation pattern between DM and non-DM cases, we assessed the extent of endomysial capillary C5b-9 deposits related to capillary density and extent of myofiber necrosis by immunohistochemistry in 12 DM and 8 control patients. We found similar numbers of C5b-9-positive myofibers in both DM and non-DM C5b-9+ cases. The distribution pattern differed as DM cases showed significantly more perifascicular capillary C5b-9 deposits as compared to non-DM cases, which presented stronger endomysial capillary C5b-9 deposits in a diffuse pattern. While total capillary density was not differing, DM patients displayed significantly more C5b-9+ necrotic fibers as compared to non-DM C5b-9+. In summary, endomysial capillary C5b-9 deposits are present in a variety of non-DM cases, however with differing distribution pattern. In conclusion, capillary C5b-9+ deposits should be assessed critically, taking into consideration the distribution pattern.

Original languageEnglish
Pages (from-to)283-291
Number of pages9
JournalNeuromuscular Disorders
Issue number4-5
Publication statusPublished - 1 Apr 2016
Externally publishedYes


  • C5b-9
  • Dermatomyositis
  • MHC-I
  • Microvascular unit
  • Muscle disease


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