073 Immunohistochemical analysis of epidermal expression of eotaxins-1, 2, and 3 in bullous pemphigoid is comparable to other eosinophil rich dermatoses

Abstract

Bullous pemphigoid is a severe autoimmune blistering diseases caused primarily by autoantibodies targeting the NC16a domain of collagen XVII. Bullous pemphigoid is characterized by an eosinophil-rich superficial dermal infiltrate, with infiltration of eosinophils into the epidermis, termed eosinophilic spongiosis. The interaction between the epidermis and this eosinophil-rich infiltrate remains unclear. We have previously demonstrated eosinophil cationic protein and eosinophil derived neurotoxin’s effect on keratinocyte expression of eotaxin-1. We sought to determine whether expression of the chemokines eotaxin-1, 2, or 3 were characteristic of bullous pemphigoid as compared to other eosinophil rich dermatoses. As such, we performed a retrospective study of 49 biopsy specimens taken from patients with either immunoserologically confirmed bullous pemphigoid (n=15), atopic dermatitis (n=12), drug eruption (n=8), arthropod assault (n=5), and non-bullous pemphigoid eosinophilic spongiosis (n=5). Lichen planus (n=4) was used as a negative control given the lack of eosinophilia in the inflammatory infiltrate. Two investigators independently assessed eotaxin staining in the basal keratinocyte layer and spinous keratinocyte layer. The gradient between basal and spinous keratinocyte expressed was calculated. We used a Kruskal-Wallis test to compare eotaxin expression between each diagnostic group, as well as to compare the gradient of expression between basal keratinocytes and spinous keratinocytes. Our analysis failed to identify any significant discrepancies in eotaxin expression amongst eosinophil rich dermatoses. Eotaxin expression appears to be a non-specific finding in inflammatory dermatoses with or without a large eosinophil infiltrate.