[The pathogenesis of psoriasis : realities and hypotheses (author's transl)].

Our pathogenic pattern, may be summarised in 7 propositions : - psoriasis is a proliferative disease of the epidermis. - the increased mitotic activity is related to imbalance of cyclic nucleotides and of prostaglandins. - this imbalance may be explained by abnormalities of the membranes of the keratinocytes. - this alteration in cell membranes results from immunological phenomena located in psoriatic epidermis. - the disturbance of immunity with production of auto-antibodies may be related to a deficiency in a sub-population of thymus-dependent lymphocytes. - this cyclic deficiency could be due to a viral agent whose penetration and persistence in the body would be dependent upon multiple genetic factors. - numerous external factors may act upon the various steps of this pathogenic chain, to worsen a pre-existent imbalance and precipitate the development of the lesions.