Intercellular IgA vesiculo-pustular dermatosis and related disorders: Diversity of IgA anti-intercellular autoantibodies

Patients with vesiculo-postular eruptions and intercellular IgA deposition are reviewed, being focused on epidermal antigens detected by the IgA autoantibodies. Histological features and reactivity patterns of the IgA antibodies with epidermis indicate that at least two distinct disorders can be distinguished: a subcorneal pustular dermatosis (SPD) type and an intraepidermal neutrophilic (IEN) type. Sera obtained from patients with the former type react with 115 and 105 kD epidermal antigens suggestive of desmocollin I and II. In contrast, one serum from the latter case binds to an indeterminate 120 kD epidermal protein. These molecules are different from those detected by IgG anti-intercellular antibodies from patients with classic pemphigus. IgA anti-intercellular antibodies from a patient with pemphigus foliaceus are also distinct from the IgA autoantibodies from a patient with the SPD type. Subcorneal pustulosis associated with linear subcorneal IgA deposition has been recognized. These findings indicate the diversity of IgA anti-epidermal autoantibodies and related disorders. We believe that the term, 'intercellular IgA vesiculo-pustular dermatosis' precisely describes the clinical and immunohistological features of the disease mediated by the IgA anti-intercellular antibodies, excluding the confusion with pemphigus and other IgA-related neutrophilic dermatoses.