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MR Vol.10 No.4 indexに戻る
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MODERN RHEUMATOLOGY
Vol.10 No.4 |
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Humoral aspects of polymyositis/dermatomyositis |
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| M. Hirakata1 |
| (1)Section of Rheumatology, Department of Internal
Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku,
Tokyo 160-8582, Japan |
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| Abstract |
| Abstract Evidence of the involvement of systemic
autoimmunity has been observed in polymyositis/dermatomyositis
(PM/DM). Autoantibodies directed against various cellular constituents
have been detected in most patients with PM/DM, and about one-third
of patients have autoantibodies (myositis-specific antibodies:
MSAs) that are found specifically in myositis patients. These autoantibodies
are closely associated with a characteristic clinical subgroup,
and therefore help in establishing the correct diagnosis, classifying
the myositis patients in a homogeneous subset, and facilitating
the clinical and treatment follow-up. Autoantibodies to six of
the aminoacyl tRNA synthetases are each associated with a similar
syndrome marked by myositis, interstitial lung disease, arthritis,
and other features constituting an "antisynthetase syndrome." Antibodies
to other cytoplasmic antigens that are involved in protein synthesis
or translation factors are seen in a small proportion of patients.
Antisignal recognition particles are associated with severe, refractory
myositis that differs significantly from antisynthetase syndrome.
Antibodies to the nuclear antigen are specifically seen in patietnts
with DM. Several autoantibodies, including anti-U1 RNP, anti-U2
RNP, anti-Ku, and anti-PM-Scl, have been associated with scleroderma-PM
overlap. In recent years, these MSAs and their antigens have been
characterized using molecular biology approaches. It is not known
if the MSAs are involved in tissue injury or the pathogenesis of
PM/DM. However, an understanding of the production mechanisms of
these autoantibodies can provide insight into the etiology of this
disorder. |
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| Key words |
| Key words Polymyositis/dermatomyositis ・ Interstitial
lung disease ・ Myositis-specific autoantibodies ・ Antiaminoacyl-tRNA
synthetase
・ Anti-SRP antibodies |
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