Immunoblot Assay as an Aid to the Diagnoses of Unclassified Cases of Pemphigus

Abstract

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.

The distribution of pemphigus vulgaris-IgG subclasses and their reactivity with desmoglein 3 and 1 in pemphigus patients and their first-degree relatives

“…However, this does not negate the fact that the WB method reveals the majority of pemphigus antigen determinants. Indeed, a couple of studies 31,32 have found a good correlation between IIF titres and immunoblotting reactivity.…”

Transition of pemphigus vulgaris into pemphigus foliaceus confirmed by antidesmoglein ELISA profile

“…Transition between the main subtypes of pemphigus, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), is rarely reported in the literature. Nevertheless when such a transition does occur, a change from PV to PF is more common 1–4 than a change from PF to PV 2,4 , 5 …”

Binding of autoantibodies is not restricted to desmosomes in pemphigus vulgaris:

“…The PF antigen is now clearly established as a 165-kDa protein named desmoglein I which is an essential component of the desmosome [6]. The PV target antigen has been identified by immunoprecipitation [5] as well as by Western immunoblotting on bovine tongue [14] or skin extract [18] and is a protein of molecular weight 130 kDa. In addition, molecular biology has shown that the PV antigen and desmoglein I are two different members of the desmoglein subfamily of desmosomal cadherins which are calcium-dependent proteins [19].…”