Procedure for the investigation of ANCA
Approved by the Section for Laboratory Immunology ČSAKI on Oct 5th 2011\
Will be published in Czech in Alergie 2012; 14(2), accessible on line on https://www.tigis.cz/casopisy/pro-lekare/alergie/itemlist/category/710-2012.html
The diagnostic chart for detection and determination of antineutrophil cytoplasmic antibodies (ANCA) is proposed in this article as the supplement recommendation of SLI ČSAKI 2005 (1).
ANCA, laboratory diagnosis
Section of Laboratory Immunology of Czech society for Allergy and Clinical Immunology (SLI ČSAKI) released methodological recommendations for laboratory diagnosis of ANCA in 2005 (1), which, unfortunately, is still broken in many laboratories. This often leads to incorrect and misleading interpretation of the results of this examination especially for diseases other than vasculitis, which are associated with ANCA positivity. SLI ČSAKI committee has therefore decided to make this addition to its 2005 recommendation, which includes the scheme for laboratory ANCA diagnosis with some updating and supplementary data. This scheme accepts the latest international consensus for diagnostic and interpretation ANCA (2) with specified terminology based primarily on publications (3) and (4).
IFA on ethanol-fixed human granulocytes is recommended as the screening assessment of ANCA (1-4). Terms C-ANCA, P-ANCA, A-ANCA, NSA and ANA should be used only for IFA results. Terms anti-XXX, where XXX is the name of particular antigen (for instance PR3) against which the positivity was tested, should be used for ANCA positivity determined by ELISA, Immunoblot or ALBIA (4). The combination of IFA and other immunoanalytical techniques increases the specificity of ANCA detection and the determination up to 100% at vasculitis keeping the sensitivity between 50-88% (8). As with all immunoanalytical methods, also in ANCA diagnosis should be expected that diagnostics from different producers can give different results in some samples and that in one sample can be present several ANCA types due to positivity against several ANCA antigens. It is sometimes impossible using IFA to distinguish and its type if ANA are present in the sample together. Screening dilution 1:10 – 1:20 for ANCA diagnosis using IFA is recommended by producers of diagnostic kits and the antibodies are determined in the IgG class even as in the screening determination of anti-XXX using other immunoanalytical methods.
Tab. 1: The overview of the diseases associated with ANCA and NSA positivity
Adapted according to [*5, **6, ***7,8], a at patients without positive ANA, NK – not known
- Král V.: Laboratory ANCA diagnostics – methodological recommendation of the committee of SLI ČSAKI. Alergie, 2005; 7(1): 57-58. In Czech, accessible on https://www.tigis.cz/images/stories/Alergie/2005/01/09_Krl_alergie_1-05.pdf
- Savige J., Dimech W., Fritzler M., Gieken J., Hagen E.C., Jennette J.C., et al.: Addendum to International Consensus Statement on testing and reporting of antineutrophil cytoplasmic antibodies. Quality control guidelines, comments, and recommendations for testing in other immune diseases. Am.J.Clin.Pathol. 2003;120: 312-318
- Highes RG, Surmacz MJ, Karim AR, Bradwell AR: Atlas od Tissue Autoantibodies. Third Edition, (Bradwel AR edit.), The Binding Site, 2008, pp. 189-206, ISBN: 070442701X
- Lochman I., Král V., Lochmanová A., Lupač J., Cebecauer L.: ANCA in the diagnosis of neutrophil-mediated inflammation. Autoimmun Rev 2010; 10(6): 295-258
- Wiik A.: Neutrophil-specific antinuclear and anti-cytoplasmic antibodies in chronic inflammatory diseases. In: Autoantibodies, 2nd Edition, (Shoenfeld Y., Gershwin M.E., Meroni P.L. editors), Elsevier, 2007, pp. 111 – 117, ISBN 10: 0-444-52763-X
- Kallenberg C.G.M.: Antineutrophil cytoplasmic autoantibodies with specificity for myeloperoxidase. In: Autoantibodies, 2nd Edition, (Shoenfeld Y., Gershwin M.E., Meroni P.L. editors), Elsevier, 2007, pp. 95-103, ISBN 10: 0-444-52763-X
- Radice A., Sabadini E., Sinicii R.A.: Antineutrophil cytoplasmic autoantibodies with specificity for proteinase 3. In: Autoantibodies, 2nd Edition, (Shoenfeld Y., Gershwin M.E., Meroni P.L. editors), Elsevier, 2007, pp. 105-110, ISBN 10: 0-444-52763-X
- Karim A.R.: Autoantibodies in vasculitis. https://medweb4.bham.ac.uk/websites/clinicalimmunology/, taken 8.7.2011