Welcome to ANApatterns.org, the official website for the International Consensus on Antinuclear Antibody (ANA) Patterns (ICAP). ICAP was initiated as a workshop aiming to thoroughly discuss and to promote consensus regarding the richness and nuances of morphological patterns observed in the indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA). The ICAP initiative was implemented at the 12th International Workshop on Autoantibodies and Autoimmunity (IWAA, São Paulo, Brazil) by members of the Autoantibody Standardization Committee (ASC), a subcommittee of the International Union of Immunological Societies (IUIS) Quality Assessment and Standardization Committee and affiliated with the Centers for Diseases Control and Prevention (CDC). The ICAP committee is operating as an ASC sub-committee.
Illustrative images were submitted for each pattern and ICAP members voted and selected the most representative ones paying attention to pixel dimension, resolution, and size. The highest ranked images for each pattern are displayed on this web site. (For an introduction of the website with some graphic images, click here.)
The ICAP committee acknowledges that the term ANA is outdated as discussed in several publications [1, 2] and yet ANA is still most commonly used in the current literature. We have proposed to use the term HEp-2 IFA to precisely describe the test in practice and used in most ICAP publications [3, 4]. Anti-Cell (AC) is used in ICAP coding of HEp-2 IFA patterns [3, 4]. Although the term anti-cellular antibody has been used in place of ANA by ICAP [2] and others [1], there is support for and reservations about its accuracy because the term “anti-cellular" also encompasses a wide spectrum of autoantibodies detected by other assays – e.g. ANCA, ASMA, APCA.
- Agmon-Levin, N., et al., International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies. Ann Rheum Dis, 2014. 73(1): p. 17-23.
- von Muhlen, C.A., et al., How to report the antinuclear antibodies (anti-cell antibodies) test on HEp-2 cells: guidelines from the ICAP initiative. Immunol Res, 2021. 69(6): p. 594-608.
- Damoiseaux, J., et al., Clinical relevance of HEp-2 indirect immunofluorescent patterns: the International Consensus on ANA patterns (ICAP) perspective. Ann Rheum Dis, 2019. 78(7): p. 879-889.
- Chan, E.K.L., et al., Report of the First International Consensus on Standardized Nomenclature of Antinuclear Antibody HEp-2 Cell Patterns 2014-2015. Front Immunol, 2015. 6: p. 412.
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Thu, 04 Jun 2026
ICAP conference at 15th International Congress on Autoimmunity 2026 This photo was taken following our session at the Autoimmunity conference in Prague. We are delighted with the success of the ICAP session and would like to express our sincere thanks to all participants, who consistently join our meetings with enthusiasm, collegiality, and a strong sense of community.
The ICAP session focused on recent advances in the interpretation and nomenclature of HEp-2 IFA patterns. Topics included the diagnostic relevance and incorporation of the new AC-30 and AC-31 patterns, the evaluation of potential new patterns under consideration (SG2NA-like, nuclear matrix, and MDA5-like), and the practical applicability of the competent and expert user classification. The session concluded with the discussion of challenging HEp-2 IFA case reports, highlighting diagnostic pitfalls and interpretation strategies. |
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Sun, 31 Aug 2025
ICAP Training Module 2 Available: AC-XX Patterns (Unusual HEp-2 IFA staining patterns not catalogued in the ICAP classification tree). To access the module, please register, log in, and click on the Training icon located in the top menu. |
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Mon, 17 Feb 2025
UPDATE OF THE CLASSIFICATION TREE
Dear ANA Patterns webpage user,
ICAP Team |
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