A case of acquired autoimmune bullous disease associated with IgM macroglobulinaemia.

A variety of autoimmune bullous dermatoses have been reported to develop in association with lymphoproliferative disorders. We report a patient with IgM macroglobulinaemia, who presented with a skin fragility similar to but somewhat milder than that seen in epidermolysis bullosa acquisita. Immunofluorescence detected circulating IgM autoantibodies reacting with the basement membrane zone, which reacted predominantly with dermal side of 1 M NaCl-split skin. Immunoblotting of the epidermal and dermal extracts with the patient's serum showed no specific reactivity. Further studies are needed to identify the antigenic molecules responsible for the IgM deposition.