Previous studies of ocular mucous membrane
pemphigoid (OMMP) have identified several components of the basement membrane zone to be
autoantigens, including
integrin β4. However, there are no extensive or definitive reported studies that address this, particularly in pure OMMP. To clarify the major
autoantigens in pure OMMP. In this study, we examined sera from 43 pure OMMP patients for both
IgG and
IgA antibodies using newly developed immunoblotting analyses with a hemidesmosome-rich fraction and various
recombinant proteins of
integrin α6β4, in addition to our routine immune-serological tests. Using a hemidesmosome-rich fraction, sera from patients with pure OMMP demonstrated reactivity of
IgG and/or
IgA antibodies to
integrin β4, BP180 and laminin-332. The reactivity of pure OMMP sera to
integrin β4 was further confirmed by immunoblotting using
integrin β4
recombinant proteins. Using concentrated supernatant of HaCaT cells, only one serum sample showed positive
IgG and
IgA reactivity to LAD-1, the ectodomain of BP180. None of the pure OMMP sera reacted with any
autoantigens on immunoblotting using normal human epidermal or dermal extracts, or purified human laminin-332.
Integrin β4 was considered to be the major and specific
autoantigen for pure OMMP. The new methods established in this study are useful for detection of various
autoantigens, particularly
integrin β4.