Activity of arthritis.

Factor analysis was used in clarifying the picture of joint inflammation. 376 arthritis patients were examined at the onset of the disease and after three years. The six factors produced are interpreted to represent six components of joint inflammation, namely the anaemic factor, the factors of clinical joint inflammation gammaglobulin activity, complement activity and acute phase, and the factor of alfa-beta globulin activity. The factor structure remained quite similar during the follow-up. This would indicate that there are certain basic aspects of inflammation which remain fairly stable from year to year.