ABSTRACT
Psoriasis is a common chronic, relapsing, noninfectious inflammatory skin disease. The concept that psoriasis has a genetic basis has been accepted for many years and it is commonly thought of as a complex trait. Heat shock proteins [HSPs] are group of proteins whose expression is increased when the cells are exposed to elevated temperature or other stress.These proteins can be induced by a range of cellular stressors including increased temperature, oxidative stress and nutritional deficiencies. Hsps have been proposed to play an important role in the pathogenesis of psoriasis. The aim of this work is to detect the expression of HSP70 in psoriasis and its correlation to the disease severity and to review potential role of HSP70 in pathogenesis and therapy of psoriasis. Skin biopsies were taken from 20 patients with different severity of untreated chronic plaque-type psoriasis and from 20 healthy volunteers. Antibodies to HSP70 were analyzed immunohistochemically. Immunoreactivity intensity distribution index [IRIDI] scores including the proportion of immunoreactive cells and their staining intensity were calculated in the basal, suprabasal, superficial as well as the whole epidermal layers of patients and controls. Results of our study revealed that differential and total IRIDI scores for HSP70 expression showed highly significant higher values in psoriatic patients compared to controls. Statistical differences were found between the different groups of patients; according to their disease severity and controls. Positive correlations also existed between IRIDI scores of patients and disease severity. Our study provides further evidence on the importance of Hsp70 in the pathogenesis of psoriasis and shows increased Hsp70 expression in psoriatic epidermis correlated to increased severity of psoriasis. To our knowledge no previous studies made correlation with HSP70 expression in psoriasis and disease severity. Finally, we are looking forwards to the application of a new therapy that targets Hsp70 or its receptor CD91 and helps in treatment of psoriasis