Osteopontin: a new facilitating factor in alopecia areata pathogenesis?

Osteopontin (OPN) is a multifunctional glycophosphoprotein secreted by many cell types, including osteoblasts, lymphocites, macrophages, epithelial cells, and vascular smooth muscle cells. It has been implicated in many physiological and pathological processes, such as cell-mediated immunity, inflammation, cell survival, and tumor invasion and metastasis. Osteopontin has multiple emerging roles in cutaneous biology and pathology and OPN involvement has been emphasized in Th1-mediated diseases such as psoriasis. Alopecia areata (AA) is a form of non-scarring hair loss affecting anagen stage hair follicles with a multifactorial autoimmune pathogenesis characterized by a prevalent Th1 cytokine profile. Given the role of osteopontin in Th1-mediated inflammation, we have postulated that OPN may be involved in AA pathogenesis. The aim of our study was to investigate plasma OPN level in alopecia areata before and after DPCP treatment. Our results showed that OPN plasma levels in patients with alopecia areata were higher than in healthy controls, but patients achieving complete recovery after DPCP treatment did not show a statistically significant reduction of OPN plasma levels.