Session Type: Poster Session (Monday)
Session Time: 9:00AM-11:00AM
Background/Purpose: To know the frequency of myositis specific antibodies (MSAs) and myositis associated antibodies( MAAs) and their relation with clinical features in patients with idiopathic inflammatory myopathy(IIM) from a Registry of Argentina.
Methods: Adults with IIM were enrolled in a retrospective way.Demographics,clinical and laboratory features were registered.Diagnosis of interstitial lung disease (ILD) was based on physician review of chest-x-ray, CT and/or pulmonary function tests.ANA were done in 291 patients, anti-Ro in 283, anti-Pm-Scl in 205,anti-Jo-1 in 263. MSAs against PL-12, PL-7, SRP and Mi-2 were done in 190 and anti: EJ, OJ, TIF1ϒ, MDA5, SAE, NXP2 ,Ku and Ro 52 were studied in 83 patients. These antibodies were detected by Immunoblot and ANA by IFI. Statistics: descriptive and Chi-squared.Stata v.11
Results: Were included 304 patients, 217(71%) women, mean age at diagnosis 46±15 years. Caucasian 42%, mestizos 37% and amerindios 8%. DM was described in 43%, PM 31,5%,IBM 1,6%, antisynthetase syndrome(ASS) in 18%, CADM 3,6%,IMNM 1,6% and overlap myositis in 21,7%. Arthritis was present in 32%, RP 34% and ILD in 26,6%.
MAAs(+): ANA 62,5%, Ro 19% and Pm-Scl: 4,8%.
MSAs (+): Jo-1 16%, Mi-2 11%, SRP and Pl-7 2,6% each and Pl-12:1,5%. Other MSAs were studied in 83 patients: anti-MDA5 13,2%, TIF1ϒ 8,4%, NXP2 3,6%,anti-SAE1,2%.Two patients had OJ and EJ.
Anti-Jo-1(+) was found in 37/41(90%) PM patients (p< 0,000), arthritis in 56% vs 31% in Jo-1(-) (p=0,005), ILD in 73% vs 15% Jo-1(-) (p< 0,000).
Anti-Mi-2 was found in 20/21 DM patients, 12 caucasians and 6 mestizos, none had ILD or anti Ro+ when were compared con Mi-2(-) 0% vs 27,3%(p=0,002) and 0% vs 26% (p=0,008),respectively, all Mi-2+ had increase CK value (100%) vs 78% Mi-2(-) p < 0,000.
The presence of MDA5 was associated with arthritis 72% vs 29%(p=0,01), ILD 63,6% vs 19,4% (p=0,005) and normal CK values 91% vs 16,6%(p< 0,000) when it was compared with patients without the antiboby. Anti Tif1 was present in 7/83 patients (8.4%),5 had DM and 2 had CADM, 1 patient had cancer.
Conclusion: Anti-Jo-1,anti-MDA5 and anti- Mi-2 were the most frequent MSAs found in our population, followed by anti- TIF1γ.
Anti-Mi-2 was present in DM while anti-Jo-1 was frequent in antisynthetasa syndrome with ILD and mainly in PM patients.
Anti-MDA5 was seen in DM with normal CK and also related to ILD and arthritis.
All patients anti-Tif1γ positive had DM and only one had cancer.
There are differences in the frequency of MSAs probably related with ethnic background or geography but the clinical phenotypes remains similar.
To cite this abstract in AMA style:Granel A, Gargiulo M, Marcos A, Gomez R, Braillard Poccard A, Costi C, Garcia M, Viola M, de la Vega M, Barrios B, Papasidero S, Kisluk B, Berbotto G, Aciar M, Crespo Espíndola M, Rivero M, Lojo M, Ponce Delgado Y, Rillo O, Puerta R, Pineda I, Capelusnik D, Movia R, Scublinsky D, Lazaro M, Gómez G. Myositis Specific Antibodies and Clinical Features in Patients from Argentina [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/myositis-specific-antibodies-and-clinical-features-in-patients-from-argentina/. Accessed May 31, 2020.
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