Changes in the expression of integrins and basement membrane proteins in benign mucous membrane pemphigoid.
OBJECTIVE
To determine the location of the subepithelial split in benign mucous membrane pemphigoid (BMMP) and its relationship to the anchoring filaments and their receptors.


METHODS
Frozen sections of lesional and perilesional oral mucosa from 10 cases of BMMP were stained, using an immunofluorescence method, for the beta-1, beta-4, alpha-3 and alpha-6 integrin subunits and for their ligands, laminin I and laminin V (kalinin). In all cases the diagnosis was confirmed by the demonstration of linear staining for IgG at the basement membrane zone. Six specimens of normal mucosa were stained for comparison.


RESULTS
Staining for integrins, laminin and kalinin in perilesional mucosa was similar to normals, although one case showed loss of alpha-6 and beta-4 . In lesional mucosa, laminin and kalinin showed strong linear staining localised to the floor of the bullae. The alpha-6 and beta-4 subunits were expressed only on the roof of the bullae but staining was weak and patchy with areas of loss. In some sections alpha-6 showed a punctate intracellular distribution similar to IgG. The distribution of alpha-3 and beta-1 was similar to that seen in normals.


CONCLUSIONS
In all cases kalinin was found on the connective tissue side of the lesions and alpha-6 beta-4 localised to the epithelial side. This shows that the split occurs at a location which separates anchoring filaments from the hemidesmosomes. Loss of the alpha-6 beta-4 integrin in the lesions and the similar intracellular staining of alpha-6 and IgG, suggest that disruption of hemidesmosomes may be a key event in the immunopathogenesis of the lesions and that the alpha-6 integrin subunit is a potential antigen in oral mucosal BMMP.
Jones
J
J
Department of Oral Pathology, Eastman Dental Institute for Oral Health Care Sciences, University of London, UK.
Downer
C S
CS
Speight
P M
PM
D008841:Actin Cytoskeleton / Q000737:chemistry / Q000276:immunology; D000328:Adult; D000368:Aged; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001485:Basement Membrane / Q000737:chemistry / Q000276:immunology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000032:analysis; D003896:Desmosomes / Q000737:chemistry; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D039201:Integrin alpha3beta1; D039503:Integrin alpha6; D039663:Integrin beta4; D016023:Integrins / Q000032:analysis*; D007365:Intercellular Junctions / Q000737:chemistry / Q000276:immunology; D007797:Laminin / Q000032:analysis; D008297:Male; D051379:Mice; D008875:Middle Aged; D009061:Mouth Mucosa / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D010390:Pemphigoid, Benign Mucous Membrane / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D011817:Rabbits; D051381:Rats; D011971:Receptors, Immunologic / Q000032:analysis*; D017474:Receptors, Laminin / Q000032:analysis; D000097794:Kalinin
D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D007074:Immunoglobulin G; D039201:Integrin alpha3beta1; D039503:Integrin alpha6; D039663:Integrin beta4; D016023:Integrins; D007797:Laminin; D011971:Receptors, Immunologic; D017474:Receptors, Laminin; D000097794:Kalinin