Clinical Relevance
First level information About Clinical Relevance & List of Abbreviations |
▶ Present to a varying degree in distinct SARD, in particular SLE, SSc, MCTD, SSc-AIM overlap syndrome, and UCTD (i.e, patients with rheumatic symptoms without a definite SARD diagnosis) (29) ▶ If SLE is clinically suspected, it is recommended to perform follow-up tests for anti-Sm and anti-U1RNP antibodies; these antigens are commonly included in the routine ENA profile; anti-Sm antibodies are included in the classification criteria for SLE (16, 30, 31) ▶ If SSc is clinically suspected, it is recommended to perform a follow-up test for anti-RNApol III antibodies (e.g., SSc profile*); the anti-RNApol III antibodies are included in the classification criteria for SSc (8) ▶ If MCTD is clinically suspected, it is recommended to perform a follow-up test for anti-U1RNP antibodies; the antigen is commonly included in the routine ENA profile; anti-U1RNP antibodies are included in the diagnostic criteria for MCTD (32) ▶ If the SSc-AIM overlap syndrome is clinically suspected, it is recommended to perform follow-up tests for anti-U1RNP and anti-Ku antibodies; these antigens are included in the routine ENA profile (U1RNP), or in disease specific immunoassays (Ku, i.e., inflammatory myopathy profile* and SSc profile*) (26, 33) ▶ In non-SARD individuals in the general population, the presence of the AC-5 pattern is not associated with the autoantigens mentioned above and most often concerns low antibody titers *Availability of the inflammatory myopathy profile, the SSc profile and the (extended) liver profile may be limited to specialty clinical laboratories. |
First level information references |
8. van den Hoogen F, Khanna D, Fransen J, et al. 2013 classification criteria for systemic sclerosis: an American College of rheumatology/European League against rheumatism collaborative initiative. Ann Rheum Dis 2013;72:1747-55. 16. Petri M, Orbai AM, Alarcón GS, et al. Derivation and validation of the systemic lupus international collaborating clinics classification criteria for systemic lupus erythematosus. Arthritis Rheum 2012;64:2677-86. 26. Betteridge Z, McHugh N. Myositis-specific autoantibodies: an important tool to support diagnosis of myositis. J Intern Med 2016;280:8-23. 29. Northway JD, Tan EM. Differentiation of antinuclear antibodies giving Speckled staining patterns in immunofluorescence. Clin Immunol Immunopathol 1972;1:140-54. 30. Satoh M, Fritzler MJ, Chan EKL. Antihistone and antispliceosomal antibodies. In: Lahita RG, Tsokos G, Buyon JP, et al, eds. Systemic lupus erythematosus. San Diego: Academic Press, 2011: 275-92. 31. Satoh M, Vázquez-Del Mercado M, Chan EK. Clinical interpretation of antinuclear antibody tests in systemic rheumatic diseases. Mod Rheumatol 2009;19:219-28. 32. Sharp GC, Irvin WS, Tan EM, et al. Mixed connective tissue disease--an apparently distinct rheumatic disease syndrome associated with a specific antibody to an extractable nuclear antigen (ENA). Am J Med 1972;52:148-59. |
Second level information |
▶ Occasionally, autoantibodies revealing the AC‐5 pattern are reactive with RNP other than U1RNP, for instance U2RNP (associated with SSc‐AIM overlap syndrome) or U11/U12RNP (associated with SSc); these autoantibodies can be detected by immunoprecipitation (13, 14). Note: Specific immunoassays for these autoantibodies are currently not commercially available. |
Second level information references |
13. Mimori T, Hinterberger M, Pettersson I, et al. Autoantibodies to the U2 small nuclear ribonucleoprotein in a patient with scleroderma-polymyositis overlap syndrome. J Biol Chem 1984;259:560-5. 14. Fretig N, Domsic RT, Rodriguez-Reyna T, et al. Anti-U11/U12 RNP antibodies in systemic sclerosis: a new serologic marker associated with pulmonary fibrosis. Arthritis Rheum 2009;61:958-65. |
FAQ |
IFA pattern changed from coarse granular to homogeneous Question: The HEp-2 IFA pattern of a patient has changed from coarse granular to homogenous after 6 months. Is it possible? |