CD1a, HAM56, CD68 AND S-100 ARE PRESENT IN LESIONAL SKIN BIOPSIES FROM PATIENTS AFFECTED BY AUTOIMMUNE BLISTERING DISEASES

Introduction: Previous research on autoimmune skin blistering diseases (ABD) has primarily focused on the humoral immune response; moreover, little attention has been given to the potential role of the antigen presenting cells (APCs) in lesional skin. Aim: The purpose of our study was to immunophenotype selected APC in the lesional skin of ABDs, utilizing immunohistochemistry (IHC) stains. Materials and Methods: We utilized IHC to stain for dendritic cells (DC), staining with CD1a, CD68, HAM56, and S-100 in lesional skin from 30 patients with endemic pemphigus foliaceus (EPF), 15 controls from the EPF endemic area, and 15 healthy controls from the USA. We also tested archival biopsies from patients with selected ABD, including 30 patients with bullous pemphigoid (BP), 20 with pemphigus vulgaris (PV), 8 with pemphigus foliaceus (PF) and 14 with dermatitis herpetiformis (DH) and 2 with epidermolysis bullosa acquisita (EBA). Results: Cells stained by CD68, HAM56 and S-100 were present in the majority of the ABD skin biopsies; these cells were located primarily in perivascular infiltrates surrounding dermal vessels subjacent to the blisters. However, these cells were also noted within the blisters, in vessels supplying dermal eccrine glands and ducts, and in areas of dermal endothelial-mesenchymal cell junction-like structures, especially in BP cases. In our CD1a staining, the number and location of positive staining cells varied with each disease, being abundant in most ABD in the epidermis suprajacent to the blisters, or in the epidermis surrounding the blister site if the blister site epidermis was missing. In the control biopsies, most did not display positive IHC staining, with the exception of a few CD1a positive cells in the epidermis Conclusion: Our findings confirm positive IHC staining for APCs in areas of the skin besides the disease blisters. Our findings suggest that the antigen presentation in ABD proceeds in areas distant from the blister site. Further studies are needed to confirm our findings, and to explore their full significance.