Human Pharmacological Conditioning of the Immune and Endocrine System: Challenges and Opportunities

In this chapter, we review recent studies on conditioned pharmacological effects on immune and endocrine responses in humans, and discuss challenges and opportunities for bringing these effects into clinical practice. By altering physiological mechanisms in part independent of pharmacological agents, pharmacological conditioning has high clinical relevance, as illustrated in some patient studies. Methodological challenges for further investigation include broadening the spectrum of opportunities for conditioned pharmacological effects, by investigating conditioning of substances that have not or not often been used before (e.g., corticosteroids) and unraveling mechanisms by which pharmacological responses become conditioned, thereby identifying characteristics that make conditioning designs effective. As an opportunity to optimize external validity, we introduce a design in which the potential of pharmacological conditioning can be pretested in the laboratory. The feasibility of this design is demonstrated by a pilot study.