Inhibitory effects of gold sodium thiomalate on the proliferation and interferon-gamma induced HLA-DR expression in human endothelial cells.

Our study was undertaken to investigate the effects of gold sodium thiomalate (GSTM) on the proliferation and HLA-DR antigen expression of human umbilical vein endothelial cells (EC). The proliferation of the EC was determined by 3H-thymidine incorporation into the EC. The expression of HLA-DR antigen on the surface of the EC was detected by an indirect immunofluorescent method using a fluorescent flow cytometer. When GSTM was added at the start of the EC culture, GSTM at a low concentration could inhibit the proliferative response of the EC to endothelial cell growth supplement. Furthermore, when the EC were cultured with recombinant interferon-gamma (rIFN-gamma) and GSTM, GSTM was also able to suppress the HLA-DR antigen expression on the surface of EC induced by rIFN-gamma. On the time-kinetic study of the effects of GSTM on the HLA-DR antigen expression induced by rIFN-gamma, the pretreatment of GSTM was able to suppress the HLA-DR antigen expression, whereas GSTM did not affect the HLA-DR antigen expression already induced by rIFN-gamma. Our findings suggest that the therapeutic effects of gold compounds in patients with rheumatoid arthritis may be attributed to the interference of the proliferation and HLA-DR antigen expression of the EC.