Expression and functional expansion of fibroblast growth factor receptor T cells in rheumatoid synovium and peripheral blood of patients with rheumatoid arthritis

Objective. Rheumatoid arthritis (RA) is an inflammatory disorder of the diarthrodial joints, characterized by fibroblast proliferation, angiogenesis, and perivascular CD4+ T cell infiltration, The present study examined the interactions between fibroblast growth factor-1 (FGF-1) and T cells. Methods. Synovial tissues from patients with RA or noninflammatory arthritis were examined for the expression of FGF-1 and its receptor, FGFR-1, by immunohistology and reverse transcriptase-polymerase chain reaction, Functional assays were used to detect enrichment of FGF-1-responsive peripheral CD4+ T cells in RA. Results. FGF-1 is abundantly expressed by rheumatoid synovium, Enhanced expression of its receptor, FGFR-1, was found in perivascular CD4+ T cells, In addition, T cells that are activated by FGF-1 are increased in the peripheral blood of patients with RA, as compared with other inflammatory conditions. Conclusion. The increased frequency of peripheral T cells that respond to FGF-1 in RA is consistent with expansion of FGFR-1-expressing T cells in the rheumatoid synovium.