IgE in the serum and on mast cells in bullous pemphigoid.

In 25 patients with bullous pemphigoid, the presence of IgE on the epidermal basement membrane (BM) and the cell membrane of mast cells was investigated by immunofluorescence microscopy. In four cases, a linear staining of the BM was found. Strongly positive fluorescence of the mast cells was found in seven cases; in seven others there was weakly positive staining. The positive staining of mast cells seemed to be related to the serum IgE level. The IgE levels in the serum samples of 30 patients were determined by the immunoradiometric assay. In 11 cases, elevated levels (greater than 400 IU/mL) were found. Circulating IgE anti-BM antibodies could be demonstrated in one of 15 serum samples by indirect immunofluorescence. Our results do not indicate that IgE-mediated mechanisms play an important role in the pathogenesis of bullous pemphigoid.