International Journal of Clinical Science and Medical Research

The diagnostic workup for systemic autoimmune diseases typically follows a sequential algorithm, beginning with antinuclear antibody (ANA) screening via indirect immunofluorescence (IIF) followed by specific anti-extractable nuclear antigen (anti-ENA) testing. Despite its robustness, clinicians frequently encounter biological discrepancies—such as ANA-positive/anti-ENA-negative or ANA-negative/anti-ENA-positive results—that can lead to diagnostic uncertainty, unnecessary medical costs, or delayed treatment. 

Objectives: This review aims to analyze the technical and biological mechanisms underlying these discrepancies and proposes an optimized, pragmatic decision-making framework based on clinical probability. 

Methods: We examine the foundations of the traditional diagnostic algorithm, focusing on the sensitivity and specificity of IIF on HEp-2 cells compared to targeted ENA panels. Technical factors such as antigen solubility ("wash-out" effect), substrate variation, and the clinical significance of specific patterns (e.g., AC-2/anti-DFS70) are evaluated. 

Results: ANA-positive/anti-ENA-negative results often stem from low-titer non-specific positivity, targets not included in standard panels, or pre-clinical phases. Conversely, ANA-negative/anti-ENA-positive cases, though rarer, are clinically critical and often involve specific antibodies like anti-SSA/Ro, which may be undetectable by standard IIF due to antigen accessibility or technical interference. 

Conclusion: Effective diagnosis requires moving beyond strict algorithmic adherence toward a "nuanced interpretation" model. An optimized approach integrates IIF titers and staining patterns with pre-test clinical probability. Ultimately, clinical suspicion must take precedence over discordant laboratory results to prevent under-diagnosis in symptomatic patients and over-diagnosis in asymptomatic individuals.

Antinuclear Antibodies (ANA), Extractable Nuclear Antigens (anti-ENA), Indirect Immunofluorescence (IIF), Diagnostic Discrepancy, Systemic Connective Tissue Diseases (CTD), HEp-2 Cell Patterns (ICAP)

1. Agmon-Levin N, Damoiseaux J, Kallenberg C, Sack U, Witte T, Herold M, et al. International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies. Ann Rheum Dis. 1 janv 2014;73(1):17‑23. doi:10.1136/annrheumdis-2013-203863 PubMed PMID: 24126457.
2. Chan EKL, Damoiseaux J, Carballo OG, Conrad K, de Melo Cruvinel W, Francescantonio PLC, et al. Report of the First International Consensus on Standardized Nomenclature of Antinuclear Antibody HEp-2 Cell Patterns 2014–2015. Front Immunol. 20 août 2015;6. doi:10.3389/fimmu.2015.00412
3. Tan EM, Feltkamp TE, Smolen JS, Butcher B, Dawkins R, Fritzler MJ, et al. Range of antinuclear antibodies in « healthy » individuals. Arthritis Rheum. sept 1997;40(9):1601‑11. doi:10.1002/art.1780400909 PubMed PMID: 9324014.
4. Damoiseaux J, von Mühlen CA, Garcia-De La Torre I, Carballo OG, de Melo Cruvinel W, Francescantonio PLC, et al. International consensus on ANA patterns (ICAP): the bumpy road towards a consensus on reporting ANA results. Autoimmun Highlights. 30 janv 2016;7(1):1. doi:10.1007/s13317-016-0075-0
5. Solhjoo M, Goyal A, Saliba F, Chauhan K. Drug-Induced Lupus Erythematosus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 [cité 5 mars 2026]. Disponible sur: http://www.ncbi.nlm.nih.gov/books/NBK441889/ PubMed PMID: 28722919.
6. Mahler M, Hanly JG, Fritzler MJ. Importance of the dense fine speckled pattern on HEp-2 cells and anti-DFS70 antibodies for the diagnosis of systemic autoimmune diseases. Autoimmun Rev. juill 2012;11(9):642‑5. doi:10.1016/j.autrev.2011.11.005 PubMed PMID: 22100330.
7. Arbuckle MR, McClain MT, Rubertone MV, Scofield RH, Dennis GJ, James JA, et al. Development of Autoantibodies before the Clinical Onset of Systemic Lupus Erythematosus. N Engl J Med. 16 oct 2003;349(16):1526‑33. doi:10.1056/NEJMoa021933
8. Provost TT, Reichlin M. Antinuclear antibody-negative systemic lupus erythematosus. I. Anti-Ro(SSA) and anti-La(SSB) antibodies. J Am Acad Dermatol. janv 1981;4(1):84‑9. doi:10.1016/s0190-9622(81)70013-6 PubMed PMID: 6970760.
9. Yang HT, Hong XP, Guo JW, Zhong XL, Liao R, Liu CL, et al. Clinical Significance of Different Profiles of anti-Ro Antibodies in Connective Tissue Diseases. J Immunol Res. 25 janv 2023;2023:9195157. doi:10.1155/2023/9195157 PubMed PMID: 36741231; PubMed Central PMCID: PMC9891828.
10. Conrad K, Röber N, Andrade LEC, Mahler M. The Clinical Relevance of Anti-DFS70 Autoantibodies. Clin Rev Allergy Immunol. avr 2017;52(2):202‑16. doi:10.1007/s12016-016-8564-5 PubMed PMID: 27350273.
11. Meroni PL, Schur PH. ANA screening: an old test with new recommendations. Ann Rheum Dis. 1 août 2010;69(8):1420‑2. doi:10.1136/ard.2009.127100 PubMed PMID: 20511607.