Childhood epidermolysis bullosa acquisita with autoantibodies against the noncollagenous 1 and 2 domains of type VII collagen : case report and review of the literature

Epidermolysis bullosa acquisita (EBA) is an acquired subepidermal bullous disease characterized by IgG autoantibodies to type VII collagen, a major component of anchoring fibrils. Most patients with EBA are adult and develop autoantibodies to the noncollagenous (NC) 1 domain of type VII collagen. We describe a 4-year-old Japanese boy presenting pruritic vesicles and tense blisters over his whole body. Immunofluorescence studies revealed linear IgG/C3 deposits along the dermal–epidermal junction of the patient's skin, and circulating IgG autoantibodies mapping to the dermal side of 1 M NaCl-split skin. By immunoblotting analysis using dermal extracts as a substrate, the patient's IgG antibodies labelled a 290-kDa protein corresponding to type VII collagen. Immunoblotting studies using recombinant proteins demonstrated that the patient's circulating autoantibodies recognized not only the NC1 but also the NC2 domain of type VII procollagen. Review of the previously reported cases and the present case suggested that patients with EBA with autoantibodies to regions other than the NC1 domain are all children younger than 10 years of age with clinical features of an inflammatory phenotype.