Neuroendocrine regulatory role of Merkel cells in the pathogenesis of psoriasis

It has been confirmed that neuroendocrine regulation involves in the pathogenesis of psoriasis, but the association between neuroendocrine and skin immune is still unknown. The present study aimed to explore the relationship of Merkel cells in the skin lesions and the pathogenesis of psoriasis. The ultrastructure of Merkel cells was observed under an electron microscope and immunohistochemistry was performed to detect the expressions of CK20, CK19, CK18, S100A7, SP and CD13 in the skin lesions of psoriasis patients and normal controls. Our results showed the neuroendocrine granules in the Merkel cells increased significantly at the progressive stage of psoriasis; the expressions of CK20, CK19 and CK18 in the skin lesions were markedly higher than those in normal controls, the CK20 expression at the progressive stage was significantly higher than that at the initial stage and recovery stage; the expressions of S100A7, SP and CD13 in the skin lesions at the progressive stage were higher than those in the initial stage and recovery stage and positively related to the CK20 expression. Merkel cells may play an important neuroendocrine regulatory role in the pathogenesis of psoriasis.