Antibodies in juvenile-onset myositis

Juvenile-onset myositis is a highly heterogeneous disease. Myositis-specific and associated autoantibodies provide a potential means of subdividing patients into clinically homogenous subgroups. Given the increasing availability of autoantibody testing, this review explores the phenotypes associated with different autoantibodies in juvenile-onset myositis and the potential clinical utility of autoantibody testing.

Autoantibodies can be identified in 60-70% of children with myositis and the recent discovery of novel myositis-associated autoantibodies in adult patients suggests this may increase in the near future. Detailed phenotype descriptions are now known for several autoantibodies commonly identified in juvenile-onset disease. Whilst there is insufficient evidence to recommend a differential treatment approach based on autoantibody status, it is becoming increasingly clear that some autoantibody subgroups are often treatment resistant and may benefit from a more aggressive approach.

The validation of nonspecialised methods for myositis-specific autoantibody detection should lead to more widely available testing. In juvenile-onset disease, this will provide detailed prognostic information and in the future may also influence approach.