The study of simple chemicals in animals and man: mechanisms of contact sensitivity.

When simple chemical are applied to the skin, a series of events ensues that under some conditions ultimately results in contact sensitivity (CS), a proven cell-mediated immune response (CMI). Since the discovery of CMI using picryl-Cl (PCl) in 1942, we have learned a great deal on the cellular mechanisms involved in CS, including the potential to treat warts, skin cancer, autoimmune disorders, and allergies. In this review we summarize some of the basic mechanisms of both the innate and acquired immune systems involved in CS.