IMMUNOPATHOGENESIS OF JUVENILE RHEUMATOID-ARTHRITIS - ROLE OF T-CELLSAND MHC

Juvenile rheumatoid arthritis (JRA) is defined as chronic arthritis of unknown etiology appearing in patients less than 16 years of age. The disease is heterogeneous and is classified as pauciarticular, polyart icular, or systemic-onset disease. A few lines of evidence suggest tha t T cells are involved in the pathogenesis of the disease. T cells inf iltrating the synovial membrane bear markers of activation and produce cytokines. The association of particular subtypes of JRA with certain HLA class II alleles provides strong evidence in favor of T cell invo lvement through an HLA-peptide-T cell receptor complex. Limited data f rom a few patients with JRA on T cell receptor transcripts from synovi al membrane or synovial fluid cells point towards oligoclonality. This further supports the concept that T cells infiltrating the synovial m embrane or extravasating into synovial fluid in patients with JRA refl ect antigen-driven T cell proliferation.