IgM-positive ocular mucous membrane pemphigoid

Abstract Purpose Ocular mucous membrane pemphigoid involves chronic, relapsing-remitting, bilateral, cicatrizing conjunctivitis. Antibodies produced by activated B cells bind, in a linear fashion, to antigens on the basement membrane of the conjunctiva. We describe a patient with ocular mucous membrane pemphigoid who demonstrated deposition of only IgM along the conjunctival basement membrane. Methods The case of a 77-year lady with left lower eyelid cicatricial entropion secondary to inferior conjunctival forniceal shortening with symblepharon formation on a background of ocular mucous membrane pemphigoid is described. Results Linear deposition of only IgM and not IgG and/or IgA at the conjunctival basement membrane was identified by direct immunofluorescence. Conclusion IgM associated ocular mucous membrane pemphigoid is a rare clinical entity. Although not a new phenomenon, it is far less commonly observed than the deposition of IgG, IgA or C3. Outcomes of immunomodulatory therapy for these patients are, reportedly, comparable to those of the ‘general’ ocular mucous membrane pemphigoid patient population.