Immunohistochemical with type IV collagen. A diagnostic tool to differentiate anti-p200 pemphigoid from epidermolysis bullosa acquisita

Abstract

Introduction: the diagnosis of autoimmune bullous diseases represents quite a challenge. When the immunofluorescence with salt-split technique has IgG and C3 at the floor of the membrane zone, several differential diagnoses are considered. Immunohistochemical with collagen IV is suggested as a complementary tool to differentiate between acquired bullous epidermolysis and anti-p200 pemphigoid.

Objectives: use immunohistochemical with collagen IV to differentiate anti-p200 pemphigoid from epidermolysis bullosa acquisita. Secondly, describe the epidemiological, clinical, and histopathological characteristics of these patients with these entities within our population.

Design: cross-sectional, retrospective, descriptive, observational, multicenter study.

Materials and methods: immunohistochemical with collagen IV was performed on biopsy specimens from patients whose direct immunofluorescence with salt-split technique showed IgG and C3 deposits on the floor of the membrane zone.

Results: 19 samples were analyzed, 12 (63.2%) testing positive for immunohistochemical with collagen IV, and 7 (36.8%) showing no labeling. Among the positive samples, 8 (42.1%) exhibited labeling on the floor of the membrane zone, interpreted as probable anti-p200 pemphigoid, and 4 (21.1%) on the roof, interpreted as acquired bullous epidermolysis.

Conclusions: immunohistochemical with collagen IV turned out to be an accessible and highly useful method that complements the diagnostic methods of autoimmune bullous dermatoses of the dermoepidermal junction. In this study, we observed a high predominance of cases with a probable diagnosis of anti-p200 pemphigoid, which reinforces the fact that this pathology is underdiagnosed due to the lack of accurate diagnostic methods.