Circulating IgA and IgE autoantibodies in antilaminin-332 mucous membrane pemphigoid.
BACKGROUND
Antilaminin-332 mucous membrane pemphigoid (MMP) is a chronic autoimmune bullous disease that is often associated with internal malignancy. IgG autoantibodies against laminin-332 in patients with MMP are well documented; however, IgA and IgE autoantibodies against laminin-332 have not yet been described.


OBJECTIVE
To characterize IgA and IgE autoantibodies binding to laminin-332 in sera from patients with antilaminin-332 MMP.


METHODS
Sera and skin samples from four patients who met the following criteria were used: (i) subepidermal blistering lesions present on the mucous membranes; (ii) in vivo deposition of IgG along the epidermal basement membrane zone of sampled skin; (iii) circulating IgG antibasement membrane zone antibodies that react with the dermal side of salt-split normal human skin; and (iv) circulating IgG autoantibodies that do not show positivity against type VII collagen or 200-kDa protein (p200 antigen) in immunoblot analysis using dermal extracts. Circulating IgG/IgA/IgE class autoantibodies against laminin-332 were determined by immunoblotting.


RESULTS
Circulating IgG autoantibodies against the gamma2, alpha3/gamma2, alpha3 and alpha3/beta3/gamma2 subunits of laminin-332 were demonstrated in sera from four patients, respectively. Serum from one of the four patients showed IgA reactivity with the alpha3/beta3/gamma2 subunits of laminin-332. Serum from one of the four patients showed IgE reactivity with the gamma2 subunit of laminin-332. The control sera failed to display IgG/IgA/IgE reactivity to laminin-332.


CONCLUSIONS
In addition to IgG autoantibodies, circulating IgA and IgE autoantibodies against laminin-332 are detectable in a subset of patients with antilaminin-332 MMP.
Natsuga
K
K
Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan. natsuga@med.hokudai.ac.jp
Nishie
W
W
Shinkuma
S
S
Moriuchi
R
R
Shibata
M
M
Nishimura
M
M
Hashimoto
T
T
Shimizu
H
H
D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology*; D001324:Autoantigens / Q000032:analysis / Q000276:immunology*; D001485:Basement Membrane / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology*; D007073:Immunoglobulin E / Q000032:analysis / Q000276:immunology*; D007797:Laminin / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010390:Pemphigoid, Benign Mucous Membrane / Q000276:immunology*
D001323:Autoantibodies; D001324:Autoantigens; D007070:Immunoglobulin A; D007797:Laminin; D007073:Immunoglobulin E