EBV gene expression not altered in rheumatoid synovia despite the presenceof EBV antigen-specific T cell clones

T cells infiltrating the rheumatoid arthritis (RA) joint are oligoclonal, i mplicating an Ag-driven process, but the putative joint-specific Ags remain elusive, Here we examine expression of selected EBV genes in RA synovia an d find no abnormal expression in RA, DNA of CMV and EBV was detectable by P CR in the synovial tissue of RA, RNA of several latent and lytic EBV genes was also detectable. However, there were no differences in EBV gene express ion in synovial tissues or peripheral blood when comparing RA with osteoart hritis, Gulf War syndrome, and other disease controls, RA synovia with high ly expanded CD8 T cell clones reactive with defined EBV peptide Ags present ed by HLA class I alleles lacked evidence of abnormal mRNA expression for t he relevant EBV Ag (BZLF1) or lacked amplifiable mRNA (BMLF1), Thus, local production of EBV Ags in synovial tissues may not be the cause of the accum ulation of T cell clones specific for these Ags, Instead, APCs loaded with processed EBV peptides may migrate to the synovium, Alternatively, EBV-spec ific T cell clones may be generated in other tissues and then migrate to sy novia, perhaps due to cross-reactive joint-specific Ags or because of expre ssion of homing receptors.