Abstract
We had three cases of rheumatoid arthritis in whom we administered a biological agent with some, but insufficient, effects, who showed a response after a dose of tacrolimus was also given.
Infriximab was used in two cases, etanercept in one. Since the effects of the biological agent were insufficient in each case, tacrolimus was additionally dosed. In all three cases, the condition went into remission, and we were able to further decrease the steroid dosage.
Although, unlike MTX, an inhibitory effect on cell proliferation was not observed with tacrolimus, which has an inhibitory effect on the production of inflammatory cytokines such as TNFα. Therefore, when some (but insufficient) effects were observed after administration of the anti-TNFα agent, those effects of the biological agent could be recovered and enhanced by reducing the TNFα production with the additional dosage of tacrolimus. Tacrolimus also had an inhibitory effect on extracellular steroid excretion by competitively binding with P-glycoproteinon the lymphocyte surface. As a result, the intracellular steroid concentration increased, which led to the reduction of the steroid dosage.
