Expression of the Rheumatoid Factor Cross-reactive ldiotype in JRA: Association with Disease Onset Subtype, Disease Activi and Disease Severity

Abstract

We previously reported that approximately one-third of patients with juvenile rheumatoid arthritis (JRA) express high concentrations of antibodies marked by the rheumatoid factor cross reactive idiotype (RCRI) in their sera (6). In order to determine if an expression of RCRI is associated with certain clinical features of the disease, we prospectively studied 49 patients with JRA over a six month period, and determined serum RCRI concentrations by inhibition ELISA. RCRI concentrations correlated significantly with the duration of morning stiffness (r = .3866, p less than .01), and the functional class (p less than .001), but not with the number of active joints. Expression of RCRI was higher in patients with systemic onset disease (p less than .03), compared to patients with pauciarticular or polyarticular disease. In patients studied on more than one occasion, the RCRI expression was relatively constant despite changes in disease activity. A subset of JRA patients with systemic onset disease, higher serum concentrations of the RCRI.

Immunoglobulin E-rheumatoid factor in juvenile rheumatoid arthritis

“…Some clinical and immunogenetic associations are well known, such as nodes, bony erosions, functional incapacities, and HLA Dw4 (DRB1*0401) and Dw14 (BRB1*0404) associations 5,6 . In one-third of patients with JRA who present idiotypic expression with cross-reaction for RF, classical RF (IgM-RF) is not observed 7 . It is possible that in this group of patients, other RF isotypes are present 8 .…”