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| Previous Nomenclature | cytoplasmic homogeneous |
| Description | It appears to be a blurry, almost homogeneous pattern throughout the cytoplasm |
| Antigen Association | tRNA-synthetases (PL-7, PL-12), ribosomal P proteins (RibP), signal recognition particle (SRP) |
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Clinical Relevance
First level information About Clinical Relevance & List of Abbreviations |
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▶ Found in patients with systemic lupus erythematosus (SLE) and the anti-synthetase syndrome (a subset of idiopathic inflammatory myopathies (IIM)), interstitial lung disease, polyarthritis, Raynaud’s phenomenon, and mechanic’s hands; these features may occur in various combinations or as an isolated manifestation, especially interstitial lung disease [1-4]. ▶ If SLE is clinically suspected, follow-up tests for antibodies to ribosomal P phosphoproteins (P0, P1, P2, C22 RibP peptide) are recommended. ▶ RibP antibodies have been associated in some studies with neuropsychiatric lupus, and in childhood-onset SLE with autoimmune hemolytic anemia [2, 5-8]. ▶ If IIM, in particular the anti-synthetase syndrome, is suspected, it is recommended to perform follow-up tests for antibodies to tRNA synthetases; antigens are included in disease specific immunoassays (i.e., inflammatory myopathy profile) [1, 4, 9]. ▶ If IIM, in particular necrotizing myopathy, is suspected, it is recommended to perform follow-up tests for SRP antibodies, an antigen included in some disease specific immunoassays (i.e., inflammatory myopathy profile) [9]. Notes: The fine distinction between AC-19 and -20 may depend on the manufacturer of the HEp-2 substrates and/or antibody concentration; antibodies to both RibP as well as tRNA synthetases may be undetected in HEp-2 IFA-screening. |
| Second level information |
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Autoantibodies to RibP: ▶ RibP antibodies have been reported in 10% of autoimmune hepatitis patients without clinical or laboratory evidence of SLE [10]. ▶ The prevalence of RibP antibodies in SLE has been reported to range between 8 – 35% in a multicenter study [6]. ▶ Less than 60% of the sera positive for RibP antibodies have the AC-19 pattern at serum screening dilutions of 1:80 or higher; the coexistence of a weak nucleolar staining is relatively common. Autoantibodies to tRNA-synthetases: ▶ Not all tRNA synthetase antibodies are positive in HEp-2 IFA; less than 50% of sera having tRNA synthetase antibodies have an AC-19 pattern at serum screening dilutions of 1:80 or higher [11]. Note: Most reports describing clinical association of RibP antibodies do not actually show correlations with the AC-19 pattern as such. |
| References |
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1. Satoh M, Tanaka S, Ceribelli A, Calise SJ, Chan EKL. A Comprehensive Overview on Myositis-Specific Antibodies: New and Old Biomarkers in Idiopathic Inflammatory Myopathy. Clin Rev Allergy Immunol. 2017;52:1-19. 2. Sciascia S, Bertolaccini ML, Roccatello D, Khamashta MA, Sanna G. Autoantibodies involved in neuropsychiatric manifestations associated with systemic lupus erythematosus: a systematic review. J Neurol. 2014;261:1706-14. 3. Yura H, Sakamoto N, Satoh M, Ishimoto H, Hanaka T, Ito C, Hasegawa T, Tanaka S, et al. Clinical characteristics of patients with anti-aminoacyl-tRNA synthetase antibody positive idiopathic interstitial pneumonia. Respir Med. 2017;132:189-94. 4. Choi MY, Satoh M, Fritzler MJ. Update on autoantibodies and related biomarkers in autoimmune inflammatory myopathies. Curr Opin Rheumatol. 2023;35:383-94. 5. Valoes CC, Molinari BC, Pitta AC, Gormezano NW, Farhat SC, Kozu K, Sallum AM, Appenzeller S, et al. Anti-ribosomal P antibody: a multicenter study in childhood-onset systemic lupus erythematosus patients. Lupus. 2017;26:484-9. 6. Mahler M, Kessenbrock K, Szmyrka M, Takasaki Y, Garcia-De La Torre I, Shoenfeld Y, Hiepe F, Shun-le C, et al. International multicenter evaluation of autoantibodies to ribosomal P proteins. Clin Vaccine Immunol. 2006;13:77-83. 7. Choi MY, FitzPatrick RD, Buhler K, Mahler M, Fritzler MJ. A review and meta-analysis of anti-ribosomal P autoantibodies in systemic lupus erythematosus. Autoimmun Rev. 2020;19:102463. 8. Bonfa E, Golombek SJ, Kaufman LD, Skelly S, Weissbach H, Brot N, Elkon KB. Association between lupus psychosis and anti-ribosomal P protein antibodies. N Engl J Med. 1987;317:265-71. 9. Betteridge Z, McHugh N. Myositis-specific autoantibodies: an important tool to support diagnosis of myositis. J Intern Med. 2016;280:8-23. 10. Calich AL, Viana VS, Cancado E, Tustumi F, Terrabuio DR, Leon EP, Silva CA, Borba EF, et al. Anti-ribosomal P protein: a novel antibody in autoimmune hepatitis. Liver Int. 2013;33:909-13. 11. Fritzler MJ, Choi MY, Mahler M. The Antinuclear Antibody Test in the Diagnosis of Antisynthetase Syndrome and Other Autoimmune Myopathies. J Rheumatol. 2018;45:444-5. |
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