Immunoexpression of CD1a and Histopathology in Lesional and Non Lesional Skin in Psoriasis: A Cross-sectional Study

Introduction: Psoriasis is a long-lasting autoimmune disease mediated by T-lymphocytes and dendritic cells. Langerhans cells are a unique population of dendritic cells found in the epidermis, where they can be identified by Cluster of Differentiation 1a (CD1a) positivity. They play an important role in the pathogenesis of psoriasis. Aim: To evaluate the utility of immunoexpression of CD1a in the early diagnosis of psoriasis and to study the histopathology of skin biopsies from clinically diagnosed cases of psoriasis. Materials and Methods: A cross-sectional study was conducted from September 2017 to August 2019 at Gandhi Hospital, Secunderabad, Telangana, India. Skin biopsies were taken from 50 patients with psoriasis from the Outpatient Department (OPD). Histopathological features in early psoriasis were studied, and CD1a immunoexpression in lesional, perilesional, and distant skin was analysed. The data were analysed using Student’s t-test with the Statistical Package for the Social Sciences (SPSS) software. Results: Half of the cases were found in two age groups: 51-60 years (15 patients, 30%) and 11-20 years (10 patients, 20%). The majority of the cases were males (36 patients, 72%). Most of the biopsies were taken from the lower limb (24 patients, 48%), followed by the back (13 patients, 26%). In this study, the average number of CD1a positive Langerhans cells was highest (54.92±5.26) in perilesional skin compared to lesional skin (30±3.96), which was statistically significant (p-value=0.04). Conclusion: Based on the observations in this study, a strong positive reaction of CD1a in perilesional skin can be used to diagnose psoriasis in the early clinical stages, before full-blown clinical psoriatic plaques have appeared. Early diagnosis may prompt physicians to initiate treatment early