T cell clones in rheumatoid arthritis (RA)

The development of T cell clones has greatly enhanced our knowledge of pathogenetic mechanisms in autoimmune diseases. Thus, it has been possible to induce experimental arthritis in susceptible animals by solely injecting arthritogenic T cell lines or clones. In contrast to many animal models, in rheumatoid arthritis the inciting antigen(s) have still not been identified. However, it has been possible to raise T cell clones from the inflammatory membrane by the addition of Interleukin-2 and/or mitogens. These clones are primarilig of the CD4+ (helper/inducer) phenotype. Molecular analyses on T cell receptor genes have not clearly shown a predominant rearrangement pattern in most studies indicating a polyclonal origin of RA synovial T cells. The availability of T cell clones will clearly help in the near future to probe for the inducing antigen(s) in inflammatory rheumatic diseases thus rendering a basis for new immunotherapeutic approaches.