JAMA Dermatol. 2022 Mar 30:e220290. doi: 10.1001/jamadermatol.2022.0290. Online ahead of print.
IMPORTANCE: Ecthyma contagiosum, or orf, is a viral zoonotic infection caused by Poxviridae. Although human orf infection is considered to follow a self-limited course, various immunological reactions may be triggered, including immunobullous diseases. In the majority of the latter cases, the antigenic target remained enigmatic.
OBJECTIVE: To characterize the predominant autoantigen in orf-induced immunobullous disease and further describe this clinical entity.
DESIGN, SETTING, AND PARTICIPANTS: This multicenter case series sought to provide detailed clinical, histopathological and immunological characteristics of a patient with orf-induced pemphigoid. Based on this index patient, serological analyses were conducted of 4 additional patients with previously reported orf-induced immunobullous disease. Immunoblotting with extracellular matrix and a recently established indirect immunofluorescence assay for detection of serum anti-laminin 332 IgG were performed.
EXPOSURES: The disease course and clinical characteristics of orf-induced immunobullous disease were observed.
MAIN OUTCOMES AND MEASURES: Orf-induced immunobullous disease is primarily characterized by anti-laminin 332 autoantibodies, predominant skin involvement, and a self-limiting course. The study provides further details on epidemiological, clinical, immunopathological, diagnostic, and therapeutic aspects of orf-induced immunobullous disease.
RESULTS: In all 5 patients, IgG1 and/or IgG3 autoantibodies against laminin 332 were identified. The ?3, ?3, and ?2 chains were recognized in 2, 4, and 1 patient(s), respectively.
CONCLUSIONS AND RELEVANCE: In this case series, laminin 332, a well-known target antigen in mucous membrane pemphigoid, was a major autoantigen in orf-induced immunobullous disease, even though predominant mucosal lesions were lacking in this autoimmune blistering disease. Orf-induced anti-laminin 332 pemphigoid is proposed as distinct clinical entity.