Immunoblot assay as an aid to the diagnoses of unclassified cases of pemphigus.

With use of an immunoblot assay for both the normal human epidermal extracts and the bovine desmosome preparation, we investigated sera from 18 patients with pemphigus, who exhibited atypical clinical or histologic features and whose diagnoses were difficult to identify. Four sera yielded a 130-kd protein band in the epidermal extracts, which is characteristic of pemphigus vulgaris. A 150-kd protein was identified by nine sera in the epidermal extracts and/or the desmosome preparation, which is known as a pemphigus foliaceus antigen. Five sera demonstrated neither antigen. These results suggest that the immunoblot technique is useful to distinguish pemphigus vulgaris from pemphigus foliaceus and can be a good tool for the diagnosis of pemphigus, especially unclassified cases.