The Depressed Synovial Complement Activity in Adult and Juvenile Rheumatoid Arthritis

Summary The synovial complement (C') activity was determined in different types of adult and juvenile arthritis.The juvenile and adult non-rheumatoid control cases, all of which showed negative sensitized sheep cell (SSC) and Latex agglutination tests showed a synovial C' activity considered to be normal.All SSC positive cases of adult and juvenile RA showed a lower synovial C' activity than the control cases, as did one SSC negative and one SSC positive case of SLE. Out of six persistently SSC negative cases of adult RA two showed a suppressed synovial C' activity and four a normal activity.In some cases the synovial C' activity was determined in two samples drawn from the same joint at varying intervals. The result of these determinations suggested that the synovial C' activity kept mainly constant for a period of about one year.Some aspects of the interpretation of the results are discussed.