The identification of autoantibodies in the sera of patients with autoimmune connective tissue diseases can be of significant value in the diagnosis, management and prognosis of these conditions, most of them with important cutaneous expression. However, the interpretation of the results depends on the type of antibody and the specific autoimmune connective tissue disease. Some autoantibodies have considerable disease specificity and thus can be of great diagnostic value (for example, anti-double-stranded DNA and Sm for systemic lupus erythematosus), but most autoantibodies fall into the disease non-specific category. So, basic understanding of key technical issues and concepts such as sensitivity, specificity, positive predictive value and negative predictive value, are important when considering the clinical significance of an antibody and the cost-benefit ratio of the various types of laboratory testing currently available for autoimmune diseases. Radioimmunoassay and immunoelectrophoresis were commonly used in the past. Immunoblot and immunofluorescence remain of important value although both, especially the former, are being slowly replaced by newer techniques such as the enzyme-linked immunosorbent assay (ELISA). ELISA is cheaper, less labor intensive, but is less specific and results need to be interpreted with caution. The classical ANA assay continues to be of great value into the world of autoimmune connective tissue diseases and understanding of its limitations is critically important to clinical and therapeutic decision-making.
|Journal||Medicina Cutanea Ibero-Latino-Americana|
|Publication status||Published - 1 May 2010|
- Autoimmune diseases