New concepts in systemic rheumatic diseases that are registered as rare diseases in Korea

This new classification system redefines the current paradigm of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and ankylosing spondylitis (AS), by focusing on the features of the disease at earlier stages. The new classification criteria of RA was devised to facilitate early diagnosis. They include the use of positive anti-cyclic citrullinated peptide antibody test and the presence of the increased level of acute phase reactants such as erythrocyte sedimentation rate and c-reactive protein. As compared to the old criteria in which only plain radiography was used to determine the joint damage, ultrasound can be regarded as a valuable tool for examining the extent of synovitis in the new criteria. In terms of SLE, immunologic criteria were intensified in the new classification criteria. They include hypocomplementemia as a single criterion and the presence of anti β2GPI antibody is considered to meet the antiphopholipid antibody criterion. The new concept of neuropsychiatric lupus is applied as well. The most recent classification criteria for AS were provided by Assessment of Spondyloarthritis International Society. They cover the whole spectrum of axial spondyloarthritis (SpA) and peripheral SpA and use magnetic resonance imaging as an important tool to assess early sacroiliac changes. In addition, they emphasize the presence of HLA-B27 gene as an important criterion. In order to prevent the undesirable organ damages, it is crucial to diagnose rheumatic diseases at early stages according to these new classification criteria and to start an early aggressive treatment. The accurate diagnosis and early targeted therapies will contribute to the improved quality of life and increased overall survival of the patients with rheumatic diseases.