007 Immunohistochemical expression of immune regulatory proteins in interface dermatoses

Abstract

Immunological therapies such as anti-programmed cell death protein 1 (PD-L1) are proving useful in the treatment of many cancers. As they inhibit self-tolerance, immunotherapies are associated with immune-related adverse events (irAEs) including rashes that histologically resemble a variety of lichenoid interface dermatoses. These cutaneous irAEs suggest PD-1/PD-L1 pathway or other immune checkpoint factors may be involved in the pathobiology of lichenoid interface dermatitis in naïve patients. We studied the staining pattern, level and prevalence of PD-L1, STING, IL-36, PD-1, CD8 and LAG-3 in skin biopsies from treatment naïve patients with five types of interface dermatitis, oral lichen planus (OLP) (n=10), cutaneous lichen planus (CLP) (n=10), chronic cutaneous lupus erythematosus (CLE) (n=11), erythema multiforme (EM) (n=11), toxic epidermal necrolysis (TEN) (n=13) and normal human skin (NHS) (n=5), by immunohistochemistry (IHC) analysis.