Abstract
Immunomodulating agents are increasingly used in clinical practice to alter the course of various malignancies, autoimmune diseases, or immunodeficiencies. Experimental data obtained in laboratory animals suggest that nearly all agents available today are likely to inhibit hepatic drug-metabolizing enzymes. Although further investigation is warranted, a direct stimulation of the reticuloendothelial system is likely to play a key role. Potentially severe drug interactions are the main clinical consequences to be considered, particularly in the field of cancer chemoimmunotherapy and vaccination. Besides immunomodulating agents, drugs with the toxic potential for immunoenhancement may also be considered in that respect.