title: Origin of threshold behaviour in psoriatic skin.
abstract: The mechanisms that lead to the psoriatic morphology are not fully elucidated. Several lines of evidence suggest that the positive feedback between keratinocytes and immunocytes plays a key role in the development of the lesions. On the other hand, little information is available on the negative regulatory controls that maintain a new homoeostasis level in psoriatic skin. We suggest here that the interplay of these two contrary feedbacks is likely to entail a hysteresis effect and that psoriasis is likely to be interpreted as a critical phenomenon characterized by a catastrophic shift of the skin from a normal to a hyperplastic state.
authors.affiliation: Department of Epidemiology and Social Medicine, Universiteit Antwerpen, Wilrijk, Belgium.
authors.forename: O
authors.initials: O
authors.lastname: Lejeune
authors.forename: T
authors.initials: T
authors.lastname: Simonart
mesh_terms: D004817:Epidermis / Q000503:physiopathology*; D025461:Feedback, Physiological; D006706:Homeostasis; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D011565:Psoriasis / Q000276:immunology / Q000503:physiopathology*; D013601:T-Lymphocytes / Q000276:immunology