An effective algorithm for the serological diagnosis of idiopathic inflammatory myopathies: The key role of anti-Ro52 antibodies

Autor: Gabriella Morozzi, Mariangela Manfredi, Valentina Grossi, Marilina Tampoia, Nicola Bizzaro, Maria Infantino, Maurizio Benucci, Elio Tonutti
Rok vydání: 2017
Předmět:
Zdroj: Clinica Chimica Acta. 475:15-19
ISSN: 0009-8981
DOI: 10.1016/j.cca.2017.10.002
Popis: Background Patients with suspected idiopathic inflammatory myopathies (IIM) are commonly tested for the presence of anti-nuclear antibodies (ANA) by indirect immunofluorescence (IIF) on HEp-2 cell substrates. However, ANA-IIF false negative tests may occur in IIM because some antigens, such as Jo1 and Ro52, may be scarcely expressed on HEp-2 cells. In addition, cytoplasmic staining is often not appropriately investigated by a specific antibody assay, leading to decreased clinical sensitivity of the ANA test. We evaluated the diagnostic impact of different strategies using different combination of myositis-related autoantibody tests. Methods Sera from 51 patients with an established diagnosis of IIM were tested for ANA by IIF on HEp-2 cells and for myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) by lineblot methods. Results Forty-four/51 (86.3%) samples tested positive with at least one of the three methods and seven were negative with all methods. Of the 44 positive samples, 9 (20.5%) tested negative for the ANA-IIF test and positive for MAA/MSA. Anti-Ro52 were the most prevalent autoantibodies in IIM patients (21/51; 41%), frequently associated with anti-Jo1 antibodies (13/21; 62%). 13 (16%) anti-Ro52 and anti-Jo1 negative samples were reactive to MSA. Conclusions Our findings suggest that when IIM is clinically suspected, the optimal diagnostic algorithm is to associate the ANA-IIF screening test with a specific test for anti-Ro52 and anti-Jo1 antibodies. Should all these tests be negative, serological tests for MSA are recommended.
Databáze: OpenAIRE
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