Myositis-specific and myositis-associated antibodies in overlap myositis in comparison to primary dermatopolymyositis: Relevance for clinical classification: retrospective study of 169 patients.
OBJECTIVE
The current study was performed in order to determine the prevalence of different myositis-specific and myositis-associated antibodies, as well as their association with clinical characteristics, disease course and response to therapy in 169 Hungarian patients with idiopathic inflammatory myopathy.


METHODS
Sera of 130 primary and 39 overlap myositis including systemic sclerosis (13), rheumatoid arthritis (12), systemic lupus erythematosus (5) and Sjögren's syndrome (9) cases were analyzed. Antinuclear antibody, scleroderma-associated antibodies (anti-centromere, anti-topoisomerase I), anti-Jo-1, anti-PL-7, anti-PL-12, anti-Mi-2, anti-SRP and anti-PM-Scl, anti-Ku, anti-SS-A, anti-SS-B, anti-U1snRNP were tested. Autoantibody results were compared with clinical characteristics, disease course of overlap versus primary myositis patients, as well as with response to therapy.


RESULTS
Associated connective tissue disease occurred in 23.1% of the patients. Myositis-associated antibodies were found in 8.5% of primary myositis patients, indicating that 11 additional primary myositis patients (23% vs. 29.6%) can be classified as overlap in all cohort according to the newly proposed diagnostic criteria. Polymyositis was found to be the most common myositis form in overlap myositis (87.2%), while scleroderma was the most common disease associated (33.3%). ANA was positive in 25.4% of primary and in 61.5% of overlap myositis cases. Altogether 39.6% of myositis patients (n=67) had autoantibodies, most commonly anti Jo-1 (18.3%) correlating with a polycyclic disease course.


CONCLUSIONS
Inclusion of myositis-specific and associated antibodies into the newly proposed diagnostic criteria for inflammatory myopathies is of great importance in order to determine subclasses and to introduce adequate therapy in time.
Váncsa
Andrea
A
Institute of Internal Medicine, Department of Rheumatology, Division of Clinical Immunology, University of Debrecen Medical and Health Science Center, Debrecen, Hungary. andrea.vancsa@gmail.com
Gergely
Lajos
L
Ponyi
Andrea
A
Lakos
Gabriella
G
Németh
Júlia
J
Szodoray
Péter
P
Dankó
Katalin
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D003430:Cross-Sectional Studies; D003882:Dermatomyositis / Q000145:classification* / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000145:classification* / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology*; D012189:Retrospective Studies; D016036:Seroepidemiologic Studies; D016896:Treatment Outcome; D055815:Young Adult
D001323:Autoantibodies; D007166:Immunosuppressive Agents