Epidermal cell thymocyte activity factor/interleukin 1 (ETAF/IL)-like activity in lymph drained from normal human skin.

Lymph derived from human skin contains lymphocytes which have a high rate of spontaneous blastic transformation in culture and are highly responsive to lectins. This phenomenon suggests that either a subpopulation of highly responsive lymphocytes is extravasated into skin, or skin tissue fluid and lymph contain humoral factors co-stimulating lymphocytes upon contact with tissue antigens. We sought to determine whether human prenodal lymph drained from normal leg skin possesses lymphokine activity. Significant augmentation of lectin induced thymocyte and autologous blood lymphocyte proliferation was produced by lymph. The augmenting activity was abrogated by incubation of lymph with anti-IL-1 antiserum. Supernatant from cultured lymph cells (lymphocytes, Langerhans cells) did not augment either thymocyte or autologous blood lymphocyte proliferation. No interleukin 2 activity was found in lymph. The data indicate that skin lymph possesses epidermal cell thymocyte activating factor/interleukin (ETAF/IL) 1-like activity which is not found in serum and that the main source of the putative lymphokine is epidermal and not migrating lymph mononuclear cells.