The skin as an immunologic organ. A tribute to Marion B. Sulzberger

The early experiments of Marion B. Sulzberger suggested that the skin played a vital role in the generation of allergic contact dermatitis and other delayed type hypersensitivity reactions. This lecture is presented in the historical context of Dr. Sulzberger's lifework and interest in mechanisms involved in delayed type hypersensitivity. I review recent studies indicating that epidermal Langerhans cells are critical for many immune responses involving the skin and that keratinocytes may also play a role in epidermal immunologic functions in that they secrete factors that may modulate various types of skin reactions. The interaction between these cells and factors and lymphoid cells indicates, as Dr. Sulzberger implied, that the skin should be viewed as an organ of immunity.