Abstract
Background: Myositis-specific autoantibodies (MSAs) define dermatomyositis (DM) and polymyositis (PM) into more homogeneous clinical subsets. Anti-p140 autoantibodies, termed MJ, were provisionally described by Oddis et al in a US cohort of patients with Juvenile DM (JDM) [1]. More recently the clinical associations of anti-p140 autoantibodies have been fully described in two cohorts of JDM patients [2-3] and the autoantigen target has been identified as nuclear matrix protein 2 [4].Objectives: We investigated the frequency and clinical associations of anti-p140 autoantibodies in adult myositis patients recruited to either the Adult Onset Myositis Immunogenetic Collaboration (AOMIC) or the Prague myositis cohort.Methods: Adult myositis patients, based on the Bohan and Peter diagnostic criteria, were recruited to AOMIC (UK) and the Institute of Rheumatology, Prague (CZ). Clinical data were collected using standardised proformas and serum samples from 487 (256 DM and 231 PM) patients were autoantibody typed by immunoprecipitation using 35S-labelled K562 cells. All samples immunoprecipiating a 140 kDa protein-band were immunodepeleted with reference adult and JDM anti-p140 (MJ) sera, to confirm the presence of anti-p140 autoantibodies. All anti-MJ positive sera were also analysed by RNA immunoprecipitation using K562 cells and immunofluorscence using HEp2 cells. Control samples from normal healthy controls and SLE, SSc and RA patients were analysed as above. Probabilities were calculated using the Fisher’s exact test with Bonferroni correction.Results: Sera from 13 (3%) adult myositis patients were positive for anti-p140 autoantibodies. These were detected exclusively in 5% of DM patients with no anti-p140 positive patients co-immunoprecipitating any other recognised autoantibodies. RNA immunoprecipitation was negative for all anti-p140 positive sera tested and immunofluorescence patterns were either weak non-specific or negative. Immunodepletion using reference sera and commercial anti-NXP-2 antibody suggested that the identity of p140 was consistent with NXP-2. The major clinical features of anti-p140-positive adults were heliotrope rash (77%), Gottron’s lesions (92%), systemic involvement including weight loss or fever (77%) and interstitial lung disease (ILD) (64%). No anti-p140 positive patients had cancer-associated myositis. In comparison to anti-p140-negative adult DM patients, the presence of anti-p140 autoantibodies was significantly associated with ILD (64% vs 28% (p=0.018)) and in contrast to anti-p140-positive JDM patients, where calcinosis was a significant feature, this was only present in one patient (9%).Conclusion: Anti-p140 autoantibodies are found in exclusively in adult DM and JDM patients. However, the frequency and clinical assocations of anti-p140 autoantibodies varies between adults and juveniles. In particular, ILD appears to be a major feature of anti-p140-positive adult patients with associated hallmark cutaneous disease.References: [1] Oddis et al, Arthritis Rheum 1997;40:S139, [2] Gunawardena et al, Arthritis Rheum 2009;60(6):1807-14,[3] Espada et al 2009:36(11):2547-51, [4] Targoff et al, Arthritis Rheum 2007;56:S787
Original language | English |
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Pages | 69(Suppl3):127 |
Publication status | Published - 2010 |
Event | EULAR - Duration: 1 Jan 1824 → … |
Conference
Conference | EULAR |
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Period | 1/01/24 → … |