Granulocyte reactive antinuclear factors in juvenile rheumatoid arthritis

The prevalence of mouse liver reactive antinuclear factors (L-ANF) and human granulocyte reactive antinuclear factors (G-ANF) was determined in sera from 34 age- and sex-matched pairs of patients with juvenile rheumatoid arthritis (JRA) and controls. Neither type of antinuclear factor was found in any of the control sera, whereas of the patient sera, 35% were L-ANF positive and 59% were G-ANF positive. 90% of the G-ANF positive sera were of the IgG class and 50% were able to fix complement. L-ANF was most frequent in female patients. Several types of ANF were associated with the polyarticular form of the disease. Such varying prevalences of ANF with disease types might indicate that JRA is a syndrome rather than a disease. In particular, the complement fixing G-ANF titre was positively correlated with parameters related to disease activity. The great variation in prevalence figures of different ANF types previously reported and the possible clinical significance of these auto-antibodies are discussed.