CHANGES IN THE DISTRIBUTION OF ACTIN-ASSOCIATED PROTEINS IN PSORIATICKERATINOCYTES - IMMUNOHISTOCHEMICAL STUDY USING CONFOCAL LASER-SCANNING MICROSCOPY

Recent studies support the presence of adherens junctions at the derma l-epidermal interface in addition to hemidesmosomes, In this area the integrin/actin-containing cytoskeleton connection occurs by means of a complex of proteins called actin-associated proteins (talin, vinculin , alpha-actinin), As previous studies have demonstrated the presence i n psoriatic lesions of marked alterations in both the basement membran e molecular composition and the polarized expression of integrins, we decided to determine whether alterations in the behaviour of the actin -associated proteins could be demonstrated, We thus undertook an immun olocalization study with monoclonal antibodies directed against talin, vinculin, and a-actinin in cutaneous biopsies taken from involved and uninvolved skin of 12 patients with extensive chronic plaque psoriasi s, The findings showed an almost total lack of reaction against talin and vinculin in the basal layer and an increased positivity against: t he proteins in the suprabasal layers, Similar, though less marked, alt erations were present in uninvolved psoriatic skin, These results, in agreement with those of previous studies, confirm serious alterations in the matrix protein/cytoskeleton connection system, and support the hypothesis that this condition may play a key role in the pathogenesis of the disease.