Severe case of pemphigoid gestationis with unusual target antigen.

We report a severe case of pemphigoid gestationis (PG) with an unusual target antigen. The patient developed a severe itchy macular rash on the abdomen during her fifth pregnancy, at 38 weeks' gestation. The disease persisted for 8 months post-partum, and could only be controlled with high doses of systemic corticosteroids and dapsone. The diagnosis of PG was confirmed by direct and indirect immunofluorescence. A linear band of IgG and C3 was detected at the epidermal aspect of salt-split skin. Immunoblotting studies revealed circulating IgG antibodies binding to a single 200-kDa protein in epidermal extracts. Immunofluorescence studies using trypsinized human keratinocytes demonstrated uniform staining around the cell peripheries, suggesting that the target antigen was not associated with hemidesmosomes. These findings differ from the usual immunological features seen in PG, and suggest further heterogeneity of the antigens involved in PG.