title: Acantholysis and spongiosis are associated with loss of syndecan-1 expression.
abstract: BACKGROUND
  Syndecan-1, a heparan sulfate proteoglycan present on the membrane of keratinocytes, functions in intercellular adhesion. Acantholysis and spongiosis are both characterized by diminished intercellular adhesion that may lead to blister formation. In spongiotic conditions, desmosomal stretching occurs prior to cell separation while in acantholytic conditions, cell separation occurs without stretching. While many of the structural relationships have been described, the molecular interactions regulating keratinocyte to keratinocyte adhesion are not yet fully understood.
  
  
  METHODS
  Sections from ten cases of Grover's disease, two pemphigus vulgaris, one pemphigus foliaceus, one bullous pemphigoid, two herpes simplex, and ten spongiotic dermatitis were stained with BB-4, a monoclonal anti-syndecan-1 antibody.
  
  
  RESULTS
  Nine of ten Grover's, all three pemphigus, and both herpes cases showed absent or markedly decreased syndecan-1 expression by acantholytic keratinocytes, with a sharp delineation from adjacent unaffected skin. The remaining Grover's case showed moderate loss of syndecan-1 expression. The pemphigus foliaceus case showed retention of staining along the basal cell layer, but expression was lost in the mid stratum spinosum. All ten spongiotic cases showed a diffuse mild decrease in staining, with loss of syndecan-1 expression surrounding microvesicles. Bullous pemphigoid, as expected, did not show loss of syndecan expression.
  
  
  CONCLUSIONS
  The loss of syndecan-1 expression evident in acantholytic conditions and, to a lesser extent in spongiotic conditions, may contribute to the decreased intercellular adhesion characteristic of these lesions.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
authors.forename: I
authors.initials: I
authors.lastname: Bayer-Garner
authors.forename: B
authors.initials: B
authors.lastname: Dilday
authors.forename: R
authors.initials: R
authors.lastname: Sanderson
authors.forename: B
authors.initials: B
authors.lastname: Smoller
mesh_terms: D000051:Acantholysis / Q000473:pathology*; D002448:Cell Adhesion; D003872:Dermatitis / Q000473:pathology; D004817:Epidermis / Q000737:chemistry / Q000473:pathology; D006561:Herpes Simplex / Q000473:pathology; D006801:Humans; D015603:Keratinocytes / Q000737:chemistry* / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000032:analysis*; D010391:Pemphigoid, Bullous / Q000473:pathology; D010392:Pemphigus / Q000473:pathology; D011509:Proteoglycans / Q000032:analysis*; D053668:Syndecan-1; D053667:Syndecans
chemical_list: D008562:Membrane Glycoproteins; D011509:Proteoglycans; C508241:SDC1 protein, human; D053668:Syndecan-1; D053667:Syndecans