Do gold drugs inhibit interleukin-1? Evidence from an in vitro lymphocyte activating factor assay.

The ability of some antiarthritic gold (I) compounds to inhibit the in vitro lympho-proliferative activity of human interleukin-1 (IL-1) in the lymphocyte activating factor (LAF) assay was investigated. Marked inhibition was seen at concentrations of auranofin (AF) and gold sodium thiomalate (GSTM) that correspond to gold levels found in the serum of patients receiving these drugs. This inhibition was not due to direct inactivation of the IL-1 molecule. Omitting 2-mercaptoethanol from the LAF assay potentiated the effect of GSTM. The antiproliferative effect of AF occurs almost immediately and probably reflects its direct cytotoxicity to stimulated lymphocytes.