A. Balsa et al., DIFFERENTIAL EXPRESSION OF THE COSTIMULATORY MOLECULES B7.1 (CD80) AND B7.2 (CD86) IN RHEUMATOID SYNOVIAL TISSUE, British journal of rheumatology, 35(1), 1996, pp. 33-37
CD4+ T-lymphocytes require two signals to become activated-antigen rec
eptor (TcR) occupancy and an antigen-presenting cell (APC)-derived cos
timulus. The latter may be provided by B7.1 (CD80) or B7.2 (CD86) on A
PC interacting with CD28 on T-cells. We have studied the expression of
these costimulatory molecules in rheumatoid and osteoarthritic synovi
al membrane. Very few B7.1-positive cells were seen in synovial tissue
from either established or early rheumatoid disease, or in rheumatoid
arthritis (RA) or osteoarthritis (OA) synovia at arthroplasty. In con
trast, B7.2 was readily detected in rheumatoid synovia, predominantly
in the lining layer, in a pattern of expression that corresponded to t
he presence of CD68-positive macrophages. Only occasional B7.2-positiv
e cells were seen in OA synovia. The presence of B7.2 but the relative
lack of expression of B7.1 may be partly responsible for the observat
ions of 'frustrated' T-cell activation or T-cell hyporesponsiveness in
the rheumatoid synovium.