IgA autoantibodies in the pemphigoids and linear IgA bullous dermatosis.
BACKGROUND
Patients with bullous pemphigoid (BP), mucous membrane pemphigoid (MMP) and pemphigoid gestationis (PG) have IgG antibodies against BP180 and BP230, components of the hemidesmosomes. Patients with linear IgA bullous dermatosis (LABD) have IgA autoantibodies against a 97/120-kDa protein which is highly homologous to a shedded fragment of the BP180-ectodomain.


OBJECTIVE
The aim of our study was to determine the incidence of IgA autoantibodies directed against BP180/BP230 in the pemphigoids and LABD and to determine the antigenic regions that are targeted by IgA autoantibodies.


METHODS
Utilizing baculovirus-expressed recombinant BP180 and BP230 proteins, we performed immunoblot analyses for IgA reactivity of sera from patients with BP (n = 30), MMP (n = 10), PG (n = 6), LABD (n = 6) and from control patients with non-related pruritic dermatoses (n = 8).


RESULTS
IgA reactivity against BP180 and/or BP230 was detected in 19/30 of the BP, in 7/10 of the MMP, in 6/6 of the LABD and in 3/6 of the PG sera, respectively, but not in the control group. In all subgroups, the major antigenic site recognized by IgA antibodies was located within the NH(2)-terminus of the BP180-ectodomain, but only a minority of the sera showed also IgA reactivity against the BP180-NC16a-domain. IgA reactivity against the central domain of BP180 was more frequently seen than against its COOH-terminus. IgA against the COOH- and NH(2)-terminus of BP230, respectively, was detected in 6/30 of the BP, 1/10 of the MMP, 1/6 of the LABD and 0/8 control sera.


CONCLUSIONS
IgA reactivity against BP180 and/or BP230 is a common finding in the pemphigoids.
Horváth
Barbara
B
Philipps University, Department of Dermatology and Allergology, Marburg, Germany. b.horvath@derm.umcg.nl
Niedermeier
Andrea
A
Podstawa
Eva
E
Müller
Ralf
R
Hunzelmann
Nicolas
N
Kárpáti
Sarolta
S
Hertl
Michael
M
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology; D016022:Case-Control Studies; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000276:immunology; D000071821:Dystonin; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000276:immunology; D024041:Non-Fibrillar Collagens / Q000737:chemistry; D006559:Pemphigoid Gestationis / Q000276:immunology*; D010390:Pemphigoid, Benign Mucous Membrane / Q000276:immunology*; D010391:Pemphigoid, Bullous / Q000276:immunology*; D011247:Pregnancy; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D000097805:Collagen Type XVII
D001323:Autoantibodies; D001324:Autoantigens; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D007070:Immunoglobulin A; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D011994:Recombinant Proteins; D000097805:Collagen Type XVII; C486268:DST protein, human