title: Inhibition of delayed hypersensitivity reaction in skin (DNCB test) by 8-methoxypsoralen photochemotherapy. Possible basis for pseudo-promoting action in skin carcinogenesis?
abstract: Fifty-five of a hundred and two subjects undergoing photochemotherapy with 8-methoxypsoralen and near ultraviolet showed an abnormally low or undetectable delayed cellular hypersensitivity reaction in the skin as judged by the dinitrochlorobenzene test. It is suggested that photochemotherapy may act as a pseudo-promotor by blocking an immunologically based control process in the skin so allowing the relatively rapid appearance of squamous skin tumours, documented elsewhere, in individuals whose skin already contains a population of potentially tumorous cells. Immune surveillance of a kind may thus operate in human skin. Impairment of delayed cellular hypersensitivity to dinitrochlorobenzene was more likely to occur with more intensive treatments and in patients with less skin pigmentation.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003043:Cocarcinogenesis; D004137:Dinitrochlorobenzene / Q000276:immunology; D005260:Female; D011564:Furocoumarins / Q000009:adverse effects*; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects*; D007157:Immunologic Surveillance; D007165:Immunosuppression Therapy; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010778:Photochemotherapy / Q000009:adverse effects*; D011565:Psoriasis / Q000188:drug therapy; D012878:Skin Neoplasms / Q000139:chemically induced*
chemical_list: D004137:Dinitrochlorobenzene; D011564:Furocoumarins