engleski

Macrophages and inflammatory dendritic cells in lesions of plaque psoriasis express TRAIL

Background: Psoriasis is regarded as a T cell-mediated inflammatory skin disease, but recent studies point to the major role of CD11c+ dendritic cells in the pathogenesis. These “inflammatory” dendritic cells act as significant source of cytokines and constitute a population equal to T cells in overall abundance in psoriatic lesions. Similar findings have been shown for CD68+ macrophages. TNF-related apoptosis-inducing ligand (TRAIL) participates in the pathogenesis of different inflammatory and autoimmune diseases, but its role in inflammatory dermatoses is largely unknown. We aimed to investigate the expression of TRAIL and its receptors DR4, DR5 and DcR2 among CD11c+ and CD68+ cells in plaque psoriasis. Patients and Methods: Immunohistochemistry for TRAIL, DR4, DR5 and DcR2 was performed on biopsies of lesional skin of patients with plaque psoriasis and skin of healthy volunteers. Double immunofluorescence was employed to examine the expression of TRAIL and its receptors in CD11c+ and CD68+ cells. Results: Expression of TRAIL and its receptors was significantly increased in lesional psoriatic dermis. As evidenced by double immunofluorescence and co-localisation analysis, both CD11c+ dendritic cells and CD68+ macrophages in the papillary dermis as well as CD11c+ and CD68+ perivascular monocyte clusters of the reticular dermis expressed TRAIL. In addition, perivascular CD68+ cells of the reticular dermis expressed receptors DR5 and DcR2. Conclusions: Results of our study identify TRAIL as an additional cytokine produced by CD68+ macrophages and CD11c+ dendritic cells in lesions of plaque psoriasis. We conclude that TRAIL/TRAIL receptor system possibly participates in the immune response in this disease.

Psoriasis; Dendritic cells; Macrophages; TNF-related apoptosis-inducing ligand

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