LAUSR

INTRODUCTION Pemphigus is a potentially life-threatening autoimmune blistering disease. To date, studies assessing the association of histopathology with clinical phenotype are lacking. We sought to evaluate the main histopathologic findings and, also, the potential links between cutaneous inflammatory infiltrates and clinical characteristics in pemphigus. METHODS We conducted a retrospective cohort study in patients diagnosed with pemphigus vulgaris (PV) and foliaceus (PF) in a referral center for autoimmune blistering diseases. RESULTS 124 patients were included in the study (97 had PV and 27 had PF). On biopsy specimens, PV was more frequently associated with the "row of tombstones" feature (36.1% vs. 11.1%, p=0.013), and PF was associated with acanthosis (44.4% vs. 23.7%, p=0.034). Acantholysis was found in the upper half of the epidermis in PF (96.3% vs. 5.15%, p<0.001), as opposed to the lower half in PV (75.2% vs. 0%, p=0.002). Patients with lymphocyte-predominant inflammatory infiltrates in lesional skin specimens presented with a higher frequency of the mucosal-dominant phenotype (25.5% vs. 9.1%, p=0.014), higher-density cellular infiltrate (100% vs. 41.6%, p<0.001), and more frequent acantholytic cells (42.6% vs. 23.4%, p=0.025). Neutrophil-predominant infiltrates in specimens from lesional skin were linked to a milder disease based on median PDAI (38.9% vs. 13.2%, p=0.036) and ABSIS score (20.2 vs. 36.3, p=0.019), while eosinophil-predominant inflammatory infiltrates were more often associated with eosinophilic spongiosis (100% vs. 23.1%, p=0.014). CONCLUSIONS Lymphocyte-predominant infiltrates in lesional skin specimens of pemphigus patients predict a mucosal-dominant phenotype, while neutrophil-predominant infiltrates are associated with a milder disease. This article is protected by copyright. All rights reserved.