Pemphigus antibodies mediate the development of an inflammatory change in the epidermis. A possible mechanism underlying the feature of eosinophilic spongiosis.

The interaction between complement-fixing pemphigus antibodies and leukocytes was investigated by the in vitro leukocyte attachment test. Attachment of eosinophils as well as neutrophils was induced by pemphigus antibodies at the intercellular space of epidermis in the presence of complement. This phenomenon was found to be produced by 7 out of 10 pemphigus sera in the indirect method using non-lesional skin as a substrate, and in 2 out of 7 biopsy specimens taken from perilesional skin without addition of any sera by the direct method. Those leukocytes bound specifically to the epidermis showed an enhanced function. i.e., vigorous incorporation of nitroblue tetrazolium dye complexes and formation of formazan crystals in the cytoplasms. The results of the present studies suggest that complement-fixing pemphigus antibodies mediate the development of an inflammatory change by inducing an infiltration of polymorphs in the epidermis, which is noted as eosinophilic spongiosis histologically.