title: Psoriatic skin reveals the in vivo presence of an epidermal IL-1 inhibitor.
abstract: Production of inhibitor(s) of IL-1 activity can be induced in keratinocytes by exposure to UVB. We describe in this study the characterization of an endogenous constitutively expressed IL-1 inhibitor which is present in extracts of human psoriatic epidermal keratome biopsies. Size-fractionated extracts of normal human epidermis did not reveal IL-1 inhibitory factor(s) activity in normal epidermis. Psoriatic epidermal extracts, however, contained virtually no IL-1 bioactivity and inhibited the activity of recombinant human IL-1 beta. This IL-1 inhibitor has a molecular weight of approximately 30 kDa and a pI of 5.3, as revealed by fast protein liquid chromatography size fractionation and chromatofocusing of psoriatic epidermal extracts. IL-1 inhibitory activity was not blocked by neutralizing anti-TGF beta monoclonal antibody. It did not have any inhibitory effect upon normal cellular proliferation but could block the IL-1 induction of IL-2 production by LBRM.33 cells as late as 4 h after exposure of LBRM.33 cells to IL-1. Thus, in vivo human psoriatic epidermis expresses an IL-1 inhibitor that specifically inhibits IL-1 activity but which appears distinct from previously described UV-induced epidermal IL-1 inhibitory activity or TGF beta.
authors.affiliation: Department of Dermatology, University of Michigan Medical School, Ann Arbor.
authors.forename: N I
authors.initials: NI
authors.lastname: Kim
authors.forename: K D
authors.initials: KD
authors.lastname: Cooper
authors.forename: G J
authors.initials: GJ
authors.lastname: Fisher
authors.forename: O
authors.initials: O
authors.lastname: Baadsgaard
authors.forename: J J
authors.initials: JJ
authors.lastname: Voorhees
authors.forename: C
authors.initials: C
authors.lastname: Hammerberg
mesh_terms: D001706:Biopsy; D002455:Cell Division / Q000502:physiology; D002853:Chromatography, Liquid; D003600:Cytosol / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000037:antagonists & inhibitors*; D007376:Interleukin-2 / Q000096:biosynthesis; D015603:Keratinocytes / Q000378:metabolism*; D011565:Psoriasis / Q000378:metabolism* / Q000473:pathology; D013950:Thymus Gland / Q000166:cytology; D014020:Tissue Extracts / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000276:immunology
chemical_list: D007375:Interleukin-1; D007376:Interleukin-2; D014020:Tissue Extracts; D016212:Transforming Growth Factor beta