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| Previous Nomenclature | actin-like |
| Description | This pattern is characterized by decorated cytoskeletal fibers, sometimes with small, discontinuous granular deposits. Typical staining show striated actin cables spanning the long axis of the cells. e.g. anti-actin, anti-non-muscle myosin. |
| Antigen Association | actin, non-muscle myosin |
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Clinical Relevance
First level information About Clinical Relevance & List of Abbreviations |
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▶ Found in patients with AIH type 1, chronic HCV infection, and celiac disease (IgA isotype); rare in SARD (17) ▶ If AIH type 1 is clinically suspected, it is recommended to confirm reactivity with smooth muscle antibodies (IgG isotype), typically detected by IIFA on rodent tissue (liver, stomach, kidney); anti-smooth muscle antibodies are included in the international criteria for AIH type 1 (17,80) ▶ F-actin is the main target antigen of anti-smooth muscle antibodies in AIH type 1; autoantibodies to F-actin are of more clinical importance than antibodies to G-actin (81–83) Notes: Although anti-F-actin immunoassays are commercially available, technical issues relating to the sensitivity of these immunoassays should be taken into consideration. |
| First level information references |
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17. Conrad K, Schössler W, Hiepe F. Autoantibodies in organ specific autoimmune diseases. a diagnostic reference. 8. 2th edn. Autoantigens autoantibodies autoimmunity, 2017. 80. Liberal R, Grant CR, Longhi MS, et al. Diagnostic criteria of autoimmune hepatitis. Autoimmun Rev 2014;13:435-40. 81. Lidman K, Biberfeld G, Fagraeus A, et al. Anti-actin specificity of human smooth muscle antibodies in chronic active hepatitis. Clin Exp Immunol 1976;24:266-72. 82. Fusconi M, Cassani F, Zauli D, et al. Anti-actin antibodies: a new test for an old problem. J Immunol Methods 1990;130:1-8. 83. Chretien-Leprince P, Ballot E, Andre C, et al. Diagnostic value of anti-F-actin antibodies in a French multicenter study. Ann N Y Acad Sci 2005;1050:266-73. |
| Second level information |
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▶ High prevalence of IgA and/or IgG type anti-actin antibody has been reported in celiac disease (1, 2) ▶ Autoantibodies to non-muscle myosin have been described in 3 patients with HCV-positive chronic hepatitis/liver cirrhosis (3) ▶ Monoclonal antibodies to non-muscle myosin have been reported in chronic lymphocytic leukemia (4). Note: Specific immunoassays for non-muscle myosin are currently not commercially available. |
| Second level information references |
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1. Pedreira S, Sugai E, Moreno ML, et al. Significance of smooth muscle/anti-actin autoantibodies in celiac disease. Acta Gastroenterol Latinoam 2005;35:83-93. 2. Clemente MG, Musu MP, Frau F, et al. Immune reaction against the cytoskeleton in coeliac disease. Gut 2000;47:520-6. 3. von Muhlen CA, Chan EKL, Peebles CL, et al. Non-muscle myosin as target antigen for human autoantibodies in patients with hepatitis C virus-associated chronic liver diseases. Clin Exp Immunol 1995;100:67-74. 4. Chu CC, Catera R, Hatzi K, et al. Chronic lymphocytic leukemia antibodies with a common stereotypic rearrangement recognize nonmuscle myosin heavy chain IIA. Blood 2008;112:5122-9. |
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