Psoriasis and cyclosporin: immunohistochemical aspects of the basement membrane

Abstract

We have demonstrated both in vivo and in vitro that Cyclosporin (CsA) treatment during psoriasis induced a regression of typical keratinocyte alterations and normalization of the basement membrane (BM). It is also known that the structure of BM implies cohesion between the networks formed by laminin and type IV collagen and that these components positively influence the cytomorphosis processes of keratinocytes. According to these results, we have evaluated, by immunohistochemical study, the behaviour of laminin and type IV collagen on psoriatic skin prior to the therapy and at the end of pharmacological treatment with CsA. This study was carried out on biopsies of involved skin taken from 12 patients with severe psoriasis and with PASI between 50 and 70. Our results can be summed up as follows: Untreated psoriasis: absence of laminin within BM; modest staining in basal keratinocytes; intense staining in suprabasal keratinocytes; discontinuous staining of Type IV collagen in the BM. After treatment: evident and continuous staining of laminin and Type IV collagen within the BM. The obtained results confirm the positive effect of immunomodulation determined by CsA in the regulation of the functional activity of cells implicated in BM component production. In conclusion, the authors discuss the pathogenesis of the disease.