Expression of VEGF and CD34 in Psoriasis Vulgaris: Correlation with Histological Grading by Trozak Histological Assessment Score

Abstract

Introduction: Psoriasis is a chronic inflammatory immunemediated cutaneous disorder. Histologically, it shows epidermal proliferation and neovascularisation in papillary dermis. Histological grading of psoriasis is done using Trozak Histological assessment Score (THS). Angiogenesis drives psoriasis. Vascular Endothelial Growth Factor (VEGF) and Cluster of Differentiation (CD34)/Micro Vessel Density (MVD) are proangiogenic cytokines in psoriasis and are overexpressed in psoriatic skin when compared to normal controls. Aim: 1) To analyse and compare the IHC expression of VEGF and CD34/MVD in skin biopsies of psoriasis cases and controls; 2) To compare the expression of VEGF, CD34/MVD with histological grade done by THS. Materials and Methods: A retrospective study was done in the Department of Pathology at Dr. B.R. Ambedkar Medical College and Hospital, Bengaluru, Karnataka, India, between September 2020 to August 2021. Twenty five cases and 25 controls (normal skin) were included in the present study. Histopathology/Immunohistochemistry (IHC) for VEGF and CD34 was performed. Suprabasilar layers of the epidermis were assessed for VEGF expression. Cell showing granular positivity within the cytoplasm was considered positive for VEGF. The mean percentage of positive cells was determined in a minimum of five areas at X400 magnification. CD34/MVD was calculated as the number of vessels in three high density locations. The MVD/High Power Field (HPF) for each individual lesion and graded as 21 per HPF. The THS was done as per standard protocol. Results: The age range in the present study was 18-68 years with male:female ratio of 1.2:1. An increased VEGF expression (p-value<0.001) in epidermal keratinocytes with accentuated MVD (p-value <0.001) in papillary dermis was seen in all 25 cases which was higher when compared to normal skin. There was positive correlation between VEGF and CD34 (Spearman's rank correlation=0.886). The mean THS was 9.56±3.4 and had positive correlation with VEGF and MVD (r=0.809 and 0.867, respectively) and was statistically significant. Conclusion: The present study shows that VEGF and CD34 are overexpressed in psoriasis utility for assessing disease severity and further provide insights for targeted therapy against VEGF pathway. Histological grading of psoriasis can give a baseline to evaluate response to treatment.

Keywords

• high power field
• immunohistochemistry
• micro vessel density
• vascular endothelial growth factor