Clinical characteristics of patients with myositis and autoantibodies to different fragments of the Mi-2 beta antigen.
OBJECTIVE
To assess the clinical implications of autoantibodies directed against different parts of the Mi-2 beta autoantigen in patients with myositis.


METHODS
A systematic assessment of the clinical, laboratory, and histological characteristics of 48 anti-Mi-2 positive patients from six European centres was made. Anti-Mi-2 autoantibodies were determined with an ELISA using four overlapping fragments spanning the entire amino acid sequence of the autoantigen. Data were compared with results for a large group of anti-Mi-2 negative patients with myositis published previously.


RESULTS
Anti-Mi-2 autoantibodies were found in dermatomyositis, polymyositis, and inclusion body myositis. In general, myositis with anti-Mi-2 autoantibodies was characterised by relatively mild disease, sometimes accompanied by extra-muscular symptoms, including arthralgia, arthritis, Raynaud's phenomenon, and interstitial lung disease. Cardiac disease was not seen, and treatment response was fair. No differences were found between patients with autoantibodies to different fragments of the Mi-2 beta antigen, except for a potentially increased risk of cancer in patients with antibodies directed to the N-terminal fragment of the autoantigen.


CONCLUSIONS
Anti-Mi-2 autoantibodies are not a marker of a specific subtype of myositis. No significant differences between patients with autoantibodies to different fragments of the Mi-2 beta autoantigen are found, with the possible exception of an increased risk of cancer in patients with antibodies to the N-terminal fragment.
Hengstman
G J D
GJ
Neuromuscular Centre Nijmegen, Department of Neurology, University Medical Centre Nijmegen, PO Box 9101, Internal Code 935, 6500 HB Nijmegen, The Netherlands. g.hengstman@neuro.umcn.nl.
Vree Egberts
W T M
WT
Seelig
H P
HP
Lundberg
I E
IE
Moutsopoulos
H M
HM
Doria
A
A
Mosca
M
M
Vencovsky
J
J
van Venrooij
W J
WJ
van Engelen
B G M
BG
D000251:Adenosine Triphosphatases / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D016009:Chi-Square Distribution; D004265:DNA Helicases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D009133:Muscular Atrophy / Q000150:complications / Q000276:immunology; D009220:Myositis / Q000150:complications / Q000276:immunology*; D009369:Neoplasms / Q000209:etiology; D010446:Peptide Fragments / Q000276:immunology; D011928:Raynaud Disease / Q000150:complications / Q000276:immunology; D018570:Risk Assessment; D018709:Statistics, Nonparametric
D001323:Autoantibodies; D001324:Autoantigens; C115323:CHD4 protein, human; D010446:Peptide Fragments; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D000251:Adenosine Triphosphatases; D004265:DNA Helicases