A case of bullous pemphigoid with antidesmoplakin autoantibodies.

Paraneoplastic pemphigus, a recently identified disease entity, is associated with autoantibodies against a variety of epidermal proteins including desmoplakins I and II, and the 230-kDa bullous pemphigoid (BP) antigen. We report an 84-year-old Japanese man who had typical clinical and histopathological features of BP, but in whom indirect immunofluorescence, using normal human skin as the substrate, revealed concomitant serum antibasement membrane zone and antikeratinocyte cell surface autoantibodies. His serum showed reactivity similar to that which is seen with antidesmoplakin monoclonal antibody on immunofluorescence of cardiac muscle and urinary bladder. With immunoblotting, using various antigen sources, the patient's serum reacted with desmoplakins I and II, and with both the 230- and 180-kDa BP antigens. Immunogold electron microscopy also indicated the presence of antidesmoplakin antibodies. Although the significance of the antidesmoplakin antibodies in this patient is unknown, the findings in this case may provide an insight into understanding the occurrence of antidesmoplakin antibodies in paraneoplastic pemphigus.