Therapeutic in vivo photochemistry: photochemical toxicity studies in humans.

Information obtained by studies of phototherapy and photochemotherapy is reviewed and some of the advantages and disadvantages of using in vivo photochemistry to treat disease are examined. Selective in vivo photochemistry is used to treat a variety of diseases. Study of the dosimetric aspects of these treatments and quantitative analysis of acute risks are instructive to individuals interested in photochemical toxicity in humans. Results from prospective short-term and long-term clinical trials are especially instructive because the model used is the intact living human. These studies provide important data about toxic, allergic, and carcinogenic aspects of photochemical toxicity, which could not be obtained in routine animal toxicity experiments. Work done to develop, explain, or improve these treatments also provides insight into molecular mechanisms of photon-induced cell injury and the sequelae of that injury.