elevated hidden igm-rf levels were detected in 57 % of all patients ( median value 0.6 iu/ml , p less than 0.01 ) , in 67 % of patients with polyarticular disease ( 1.1 iu/ml , p less than 0.005 ) , in 62 % of the group with monoarticular disease ( 0.6 iu/ml , p less than 0.02 ) , and in 60 % of the group with systemic disease ( 0.6 iu/ml , ns ) .
C0012634
disease
C0442893
systemic disease