title: Cellular responses to the intradermal injection of recombinant human gamma-interferon in lepromatous leprosy patients.
abstract: The local response to a single intradermal injection of 10 micrograms recombinant gamma-interferon (rIFN gamma) has been studied in 17 patients with lepromatous leprosy. Of these, 2 patients additionally received two intradermal injections of 10 micrograms rIFN gamma at another site. The results were compared with those of 3 patients who received three injections of the same dose at a single site in an earlier study. One to 7 days after lymphokine administration 4-mm punch biopsies were obtained and examined for cellular alterations in the dermis and epidermis. This allowed a kinetic analysis of mononuclear cell infiltration, keratinocyte proliferation and differentiation, and Langerhans cell redistribution. At 24 hours, the migration of large numbers of helper T cells and monocytes was already prominent and associated with induration. Mononuclear cell accumulation peaked at 72 hours but then persisted for 5-7 days. Only small numbers (one-third or less of total T cells) of suppressor/cytotoxic T cells were present at any time, and granulocytes were absent. Two daily injections of rIFN gamma led to a more intense accumulation of cells. Ten micrograms of rIFN gamma resulted in enhanced keratinocyte proliferation, Ia expression, and thickening of the epidermis. At 24-48 hours major histocompatibility Class II (Ia) antigen was first noted on the dividing cells of the basal layer. By 72-96 hours the entire epidermis exhibited strong expression of Ia antigen on cell surfaces. Repeated doses of lymphokine accentuated these changes and resulted in a more prompt keratinization and sloughing of this layer. Whereas a single dose of rIFN gamma resulted in the upward movement of T6+ Langerhans cells (LCs) in the epidermis, two injections led to a 50% reduction in their numbers and three doses were associated with an almost total loss of detectable T6+ LCs from the epidermis. These are probably sloughed along with keratinocytes. In contrast to the situation with a delayed immune response in the skin (purified protein derivative), no LCs accumulated in the dermis in association with helper T cells.
mesh_terms: D000818:Animals; D004817:Epidermis / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007700:Kinetics; D007801:Langerhans Cells / Q000187:drug effects; D007918:Leprosy / Q000276:immunology*; D008214:Lymphocytes / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D051379:Mice; D009000:Monocytes / Q000473:pathology; D011994:Recombinant Proteins / Q000494:pharmacology; D012867:Skin / Q000276:immunology* / Q000473:pathology
chemical_list: D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; D007371:Interferon-gamma