Ls. Chan et al., LAMININ-6 AND LAMININ-5 ARE RECOGNIZED BY AUTOANTIBODIES IN A SUBSET OF CICATRICIAL PEMPHIGOID, Journal of investigative dermatology, 108(6), 1997, pp. 848-853
We characterized basement membrane zone (BMZ) autoantigens targeted by
autoantibodies (AAb) from patients with cicatricial pemphigoid, Serum
from a patient with severe oral cicatricial pemphigoid contained IgG
anti-BMZ AAb, The AAb labeled a lower BMZ component on salt-split skin
and localized to the lower lamina lucida/lamina densa by direct and i
ndirect, immunoelectron microscopy (IEM) but did not label blood vesse
ls, The AAb did not react with EHS laminin-1 and type IV collagen, pep
sinized human type IV collagen, recombinant entactin, or NC1 domain of
type VII collagen by dot blotting and western blotting. We focused ou
r studies on the laminin family, as laminin-5 was identified as an aut
oantigen in cicatricial pemphigoid, Culture-conditioned media from nor
mal keratinocytes (containing laminin-6 and laminin-5) and JEB keratin
ocytes (containing laminin-6 but not laminin-5) were studied by wester
n blotting, Under nonreducing conditions, the patient's AAb recognized
a 600-kDa protein (laminin-6) intensely and a 400-kDa protein (lamini
n-5) weakly in normal keratinocyte medium even though abundant laminin
-5 was present, In JEB keratinocyte medium, however, the 600-kDa prote
in (laminin-6) alone was recognized by the patient's AAb, The AAb also
immunolabeled BMZ of JEB skirt that lacked laminin-5, The AAb from th
is patient and two other patients with anti-laminin-5 cicatricial pemp
higoid immunoprecipitated both laminin-6 and laminin-5, Taken together
, the results of IEM, nonreducing western blotting, immunoprecipitatio
n, and JEB skin BMZ immunolabeling indicate that laminin-6, as well as
laminin-5, is identified by the AAb from a subset of cicatricial pemp
higoid patients. We propose the name ''anti-laminin cicatricial pemphi
goid'' for this subset.