[Classification of early arthritis patients and how to determine disease severity].

Recent clinical studies of rheumatoid arthritis reveal that therapeutic intervention early in rheumatoid arthritis leads to less joint damage, indicating the importance of early diagnosis of RA for improvement of prognosis. According to the data of our "Early Arthritis Prospective Cohort", we have found that early arthritis patients, described as undifferentiated arthritis, progress to rheumatoid arthritis at high frequency if the patients positive with anti-cyclic citrullinated peptide antibody (anti-CCP antibody) and bone marrow edema at the entry. In addition, we are going to classify the pathologic status (disease severity) of early arthritis patients by serologic variables, radiographic findings and genetic analysis.