The influence of haematoporphyrin derivative and visible light on murine skin graft survival, epidermal Langerhans cells and stimulation of the allogeneic mixed leucocyte reaction.

The influence of combined photochemical treatment with a haematoporphyrin derivative and visible light on antigen-presenting cells was evaluated. Treatment of murine skin grafts with this procedure prolonged their subsequent survival on allogeneic recipients. The haematoporphyrin derivative and light decreased the ATPase activity of epidermal Langerhans cells in murine skin. When stimulator cells in a human allogeneic mixed leucocyte reaction were treated with the haematoporphyrin derivative and light, they lost their stimulatory capacity. It is proposed that the haematoporphyrin derivative and visible light interfere, on analogy with ultraviolet radiation, with the function of antigen-presenting cells.