Outlines for future research

such as hydration, barrier function, skin penetration by various compounds, and early stages of contact reactions, whether irritant or immune. In this context, the diverse interactions between T lymphocytes and the presenting antigen cells, macrophages, and Langerhans cells remain to be explained, as does the functional significance of the numerous cytokines, including the interleukins (ILs), especially IL-l, IL-Z, and IL-4, the interferons, and the intercellular adhesion molecules, such as intercellular adhesion molecule 1 (ICAM-l).’ These recently discovered molecules seem to be involved in skin inflammatory processes and in antigen presentation. The continued experimental exploration of the immune mechanisms of contact allergy by immunologists can be confidently expected to provide valuable data, not only of theoretical importance, but also of practical value in the prevention of and desensitization in contact hypersensitivity.2