Immunohistochemical Expression of p53 and bcl-2 in Psoriasis

Abstract

Introduction: Apoptosis plays a major role in maintaining the balance between cellular proliferation and cell death in the skin. Blockage of apoptosis has been implicated as one of the contributing factors in the pathogenesis of psoriasis. P53 has a role in induction of cell cycle arrest, apoptosis as well as regulation of cell proliferation, bcl-2 is anti-apoptotic protein. Previous studies have reported controversial results relating to their expression in psoriatic skin. Aim: To evaluate the immunohistochemical expression of p53 and bcl-2 in the epidermis, basal cells and lymphocytes of psoriatic skin and compare it with the adjacent perilesional skin. Materials and Methods: This cross-sectional study was conducted in Hind Institute of Medical Sciences, Safedabad, Barabanki, Uttar Pradesh, India from June 2016 to December 2017. Fifty cases of psoriasis were included and punch skin biopsies including a small part of perilesional skin was taken. The sections were studied for the presence of immunohistochemical expression of p53 and bcl-2 using scoring systems. The perilesional part of the biopsy was used for comparing the histopathological and immunohistochemical expressions. The student t-test was used for comparison of groups using Statistical Package for the Social Sciences (SPSS) version 23.0 program and a p-value of <0.05 was taken as statistically significant. Results: The age of the patients ranged from 15-68 years. Majority of the patients were males comprising 32 out of 50 cases (64%). The most common site was the extensor surfaces of limbs. The histopathological findings of psoriasis, such as acanthosis, spongiosis, suprapapillary thinning, dilated dermal vessels and dermal lymphocytic infiltrate was seen in all 50 cases of the lesional skin (100%). Dermal lymphocytic infiltrate was the most common finding in the perilesional skin and was observed in 21 cases (42%). Statistically significant immunohistochemical expression of p53 was seen chiefly in the epidermis, while bcl-2 expression was seen in the dermal lymphocytes of psoriatic (lesional) skin. Conclusion: The immunohistochemical expression of p53 in the epidermal keratinocytes of the lesional skin in psoriasis is suggested to be of wild type in response to frequent DNA damage in the actively cycling cells of epidermis. The expression of bcl-2 in the dermal lymphocytes could point towards its role in promoting the chronic inflammatory and recurrent nature of psoriatic lesions.

Keywords

• acanthosis
• apoptosis
• erythema
• psoriasis vulgaris
• spongiosis