Laboratory assessment in musculoskeletal disorders.

Autoimmune-mediated musculoskeletal disorders feature the presence and pathogenic role of circulating autoantibodies and autoreactive T cells. Determination of these autoantibodies provides crucial information to establish the diagnosis of these diseases. In addition, the determination of these antibodies may have prognostic value or may be used to monitor response to treatment or to predict relapse of disease. We first address the main characteristics of several autoantibody assays that are considered to be clinically most relevant. These include rheumatoid factor (RF), anti-cyclic citrullinated antibody (anti-CCP), antinuclear autoantibodies (ANA), anti-double-stranded DNA antibodies, antibodies to extractable nuclear antigens (ENA), and antineutrophil cytoplasmic autoantibodies (ANCA). Subsequently we provide a brief overview of the most important musculoskeletal disorders, such as rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis/CREST, polymyositis/dermatomyositis and vasculitis. Our main goal was to address the role of the determination of autoantibodies in the diagnosis and follow-up of musculoskeletal disorders.