Aim: To detect the expression of B and T lymphocyte attenuator (BTLA) antigen in synovial tissues from rheumatoid arthritis (RA) patients.
Methods: The expression and distribution of BTLA antigen was analyzed by immunohistochemistry. Moreover, fluorescence double-staining was used to further identify the cell types expressing BTLA.
Results: Immunohistochemical analysis revealed that a great deal of BTLA positive cells were found in RA synovium, and fluorescence double-staining further demonstrated that BTLA positive cells were CD3(+); T cells, CD68(+); macrophages, and occasionally CD31(+); endothelial cells. In contrast to other members of B7 superfamily, the expression of BTLA was also found on B7-H1(+);, B7-H4(+); and HVEM(+); cells, while it was absence on B7-DC(+); cells as well as B7-H3(+); cells.
Conclusion: The expression of BTLA has been observed on the surface of several kinds of cells within synovial tissues of RA patients, which indicates this signal might be involved in the regulation of local T cell activation and the pathogenesis of RA.