Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Dermatomyositis (DM) and polymyositis (PM) are forms of IIM that involve skeletal muscle as well as many other organs. As in other systemic rheumatic diseases the IIM are characterized by the production of various autoantibodies that are of diagnostic and prognostic help because they are frequently associated with specific clinical subgroups. To determine the frequency of anti-nuclear antibodies (ANA), myositis specific autoantibodies (MSA) and myositis associated autoantibodies (MAA) in Latin-American patients with IIM from various centers of Mexico, Central and South America.
Methods: 155 serum samples from unselected patients with IIM were included in the study: 109 from México, 20 from Peru, 16 from Dominican Republic and 10 from Argentina. DM and PM were diagnosed according to the Bohan and Peter criteria. ANA were detected by IIF on HEp-2 cells (Antibodies Inc., Davis, CA, USA), MSA and MAA were tested by a line immunoassay method (Euroline Myositis Antigens Profile 3) (Euroimmun, Luebeck, Germany). In addition, anti-HMGCR was detected with an addressable laser bead immunoassay (ALBIA: Luminex)
Results: Of the 155 IIM patients, 106 (68%) had DM, 37 (24%) PM and 12 (8%) JDM. Mean age 42.4 (6-79 years), 117 (75%) were female and 38 (25%) were male. The frequency of ANA was 51%, being more frequent in Mexico (54%) than in Argentina (50%), Dominican Republic (44%), and Peru (40%); not statistically significant (p = 0.20; Chi square test for trend). The most frequent patterns were speckled (82%) and cytoplasmic (10%). The highest dilution (1:1,280) was present in 42% of the patients. The frequency of MSA was Mi-2 (21%), HMGCR (6%), Jo-1 (2.5%), PL-12 (2.5%), SRP (2.5%), PL-7 (1.2%), EJ (1.2%), and OJ (1.2%). Anti-Jo-1 was not present in the sera from Peru and Dominican Republic. The frequency of MAA was Ro-52/TRIM21 (18%), PM-Scl75 (3.8%), Ku (3.8%) and PM-Scl100 (1.5%); however, anti-Ro52/TRIM21 was not detected in sera from Peru and Dominican Republic.
Conclusion: This is the first study of ANA, MSA and MAA from eight centers in the PANLAR myositis study group. We observed a general prevalence of 51% of ANA by IIF, but more frequent in Mexico (54%). In relation to MSA and MAA, anti-Mi-2 was the more frequent (21%), a finding that is in contrast to studies in other geographic areas in which anti-synthetase antibodies tend to be more common. In general, we found some differences in the presence of these two groups of antibodies in the Latin-American countries included in this study.
To cite this abstract in AMA style:Gonzalez-Bello Y, Garcia-Cerda D, Medrano-Ramírez G, Navarro-Zarza JE, Andrade-Ortega L, Maradiaga-Ceceña M, Cardenas-Anaya A, Nava-Zavala AH, Orozco-Barocio G, Rojo-Mejia A, Loyo E, Gottschalk P, Gómez G, Fritzler MJ, Garcia-De La Torre I. Frequency of Antinuclear (ANA), Myositis-Specific (MSA) and Myositis-Associated Antibodies (MAA) in Patients with Idiopathic Inflammatory Myopathies (IIM) from Mexico, Central and South America Centers: Data from the Panlar Myositis Study Group. [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/frequency-of-antinuclear-ana-myositis-specific-msa-and-myositis-associated-antibodies-maa-in-patients-with-idiopathic-inflammatory-myopathies-iim-from-mexico-central-and-south-america-center/. Accessed October 20, 2021.
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