Effects of sodium aurothiomalate on the polyclonal immunoglobulin secretion by human mononuclear cells in vitro

Sodium aurothiomalate (GSTM) inhibited the pokeweed mitogen induced plaque forming cell (PFC) response in a dose dependent manner. This inhibition was irreversible as preincubation for 2 h with the drug followed by washes still caused a suppression of the PFC response. Pretreatment of the different mononuclear cell populations necessary for the PFC response with GSTM for short periods (2-24 h) showed that both macrophages (M phi) and B lymphocytes were inhibited by the drug but that T cells were resistant. In the case of GSTM treated M phi the response was restored partially with exogenous interleukin-1, and completely with the addition of 20% fresh M phi. Our results show that the inhibition of polyclonal immunoglobulin secretion by human mononuclear cells in vitro is due to an effect of GSTM on both M phi and B lymphocytes. This may explain the decrease in serum immunoglobulin levels seen in patients receiving chrysotherapy.