Morphologic and functional evidence for release of mast-cell products in bullous pemphigoid.

We studied nine patients with bullous pemphigoid, a generalized cutaneous eruption- for evidence of mast-cell involvement during development of lesions. As in other reports, six of nine patients demonstrated a serum antibody directed against the epidermal basement-membrane zone. Direct immunofluorescence studies of lesions revealed depostion of immunoglobulin and complement proteins at the basement-membrane zone in six of nine and nine of nine patients, respectively. Participation of mast cells was suggested by a sequence of pathologic alterations in which there was progressive mast-cell degranulation and late eosinophil infiltration. In addition, a factor chemotactic for human eosinophils with the size and charge characteristics of the eosinophil chemotactic factor of anaphylaxis was identified in blullous fluid. The data indicate that, in addition to activation of the complement system, involvement of mast cells is an early and continuing event in the development of the cutanenous lesions of bullous pemphigoid.