Idiopathic Inflammatory Myopathies

Inflammatory myopathies are uncommon diseases affecting primarily muscle tissue and / or the skin.  Diagnosis is difficult since overlap syndromes with features of other diseases such as Scleroderma are frequent.

 Polymyositis / Dermatomyositis

Certain autoantibodies have been considered 'myositis specific' because most patients with them have myositis. The most common autoantibodies are the anti-synthetases directed against aminoacyl tRNA synthetases.  These include Jo-1, PL7, PL12, other autoantibodies that are useful include SRP, Mi-2, Ku, Anti-PMScl is often considered a myositis autoantibody since 80% of patients have myositis.

These autoantibodies tend to produce cytoplasmic patterns HEp2 cells by IFA, except anti-Mi-2 which are nuclear speckled and anti-PMScl which are nucleolar.  BlueDiver Dot kits allow the characterisation of the autoantibodies relating to PM/DM.  Kits and the BlueDiver Instrument are available through CLS.

Resources