Anticytokeratins are a potential source of false-positive indirect immunofluorescence assays for C-ANCA

Johannes Streicher*, Barbara Fabian, Kurt Herkner, Herwig Pointner, Peter M. Bayer

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

7 Citations (Scopus)


Antibodies to neutrophil cytoplasmic antigens (ANCA) targeted toward granule enzymes have been recognized as a valuable diagnostic tool in the detection of Wegener's granulomatosis and systemic vasculitides. However, the most commonly used method of detection, the indirect immunofluorescence assay, is prone to false-positive results due to antibodies of different pathological significance either targeted to, or cross-reacting with, similarly distributed epitopes. Using double immunofluorescence, the present study demonstrates that anticytokeratin antibodies are able to produce false- positive C-ANCA immunofluorescence assays. In addition, a case of natural appearance of cytokeratin-reactive antibodies causing a false-positive 'pseudo-ANCA' staining pattern in a patient presenting with sepsis is reported. Since the expression of cytokeratins is almost exclusively confined to epithelial cells, the most plausible explanation for both phenomena is a crossreaction of anticytokeratin antibodies with granule associated epitopes. Due to the natural appearance of anticytokeratin antibodies in association with a variety of other pathologic entities, it is of crucial importance for the diagnostic significance of the C-ANCA immunofluorescence assay to exclude anticytokeratin caused false-positive results. It is shown that supplementary indirect immunofluorescence tests performed on cultured human epithelial cells readily distinguish anticytokeratin caused 'pseudo-ANCA' from true C- ANCA.

Original languageEnglish
Pages (from-to)54-59
Number of pages6
JournalJournal of Clinical Laboratory Analysis
Issue number1
Publication statusPublished - 1998
Externally publishedYes


  • Anticytokeratin antibodies
  • NCA
  • NCA detection
  • Streptococcal sepsis
  • Wegener's granulomatosis

ASJC Scopus subject areas

  • Immunology and Allergy
  • Hematology
  • Public Health, Environmental and Occupational Health
  • Clinical Biochemistry
  • Medical Laboratory Technology
  • Biochemistry (medical)
  • Microbiology (medical)


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