Co-localization of IgA and TG3 on healthy skin of coeliac patients.
BACKGROUND
Dermatitis herpetiformis (DH), the skin's expression of coeliac disease (CD), is induced by the presence of IgA antibodies and epidermal transglutaminase (TG3) as the main autoantigen, stored in the papillary dermis and on the vessel walls.


OBJECTIVE
To evaluate the presence of IgA and TG3 deposits, considered to be the first step in inducing DH, in healthy skin of coeliac patients without cutaneous manifestations.


METHODS
Punch biopsies were taken from 11 consecutive coeliac patients, two with DH and nine without cutaneous manifestations, three of whom were adhering to a gluten-free diet (GFD), and evaluated for the presence of deposits in the upper dermis and vessel walls by immunofluorescence and confocal microscopy.


RESULTS
In coeliac patients affected by DH we found the presence of IgA and TG3 deposits mainly on the upper dermis, but also in vessel walls. In all coeliac patients without DH and also in those patients who were following a strict GFD, we found widely variable deposits of IgA and TG3 in both the papillary dermis and the vessel walls, although a lower intensity of the fluorescence signal was detected than with coeliac patients affected by DH. Double immunostaining with anti-IgA and anti-TG3 antibodies showed a strong co-localization in the upper dermis in patients with DH and a weaker co-localization in those without DH.


CONCLUSIONS
We have demonstrated the presence of IgA and TG3 deposits in the healthy skin of coeliac patients, which are considered to play a central role in the pathogenesis of DH.
Cannistraci
C
C
S. Gallicano Dermatological Institute, Rome, Italy.
Lesnoni La Parola
I
I
Cardinali
G
G
Bolasco
G
G
Aspite
N
N
Stigliano
V
V
Picardo
M
M
D000328:Adult; D000906:Antibodies / Q000032:analysis*; D000936:Antigen-Antibody Complex / Q000032:analysis / Q000276:immunology; D001324:Autoantigens / Q000032:analysis*; D001706:Biopsy; D001808:Blood Vessels / Q000201:enzymology / Q000276:immunology; D002446:Celiac Disease / Q000178:diet therapy / Q000276:immunology*; D003874:Dermatitis Herpetiformis / Q000276:immunology; D020405:Dermis / Q000098:blood supply / Q000201:enzymology / Q000276:immunology; D018753:Diet, Protein-Restricted; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D005983:Glutens; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D008297:Male; D018613:Microscopy, Confocal; D012867:Skin / Q000098:blood supply / Q000201:enzymology / Q000276:immunology*; D011503:Transglutaminases / Q000032:analysis* / Q000276:immunology
D000906:Antibodies; D000936:Antigen-Antibody Complex; D001324:Autoantigens; D007070:Immunoglobulin A; D005983:Glutens; C498712:TGM3 protein, human; D011503:Transglutaminases