Study on the expression of RXRalpha in patients with psoriasis vulgaris.

Retinoic acid regulates keratinocyte proliferation and differentiation--processes that are disturbed in psoriatic skin--via binding to nuclear receptors, including retinoic acid receptor (RAR-alpha,beta,gamma) and the common heterodimer partners (RXR-alpha,beta,gamma). By RT-PCR and immunohistochemistry methods, the expression of RXRalpha was studied in psoriatic skin and controls. The expression of RXRalpha was down-regulated in patients with psoriasis; moreover, its level was related to the stage of the disease; in the progressive stage of the disease, the level of the RXRalpha was lower than in the stable stage. The results suggest that retinoid signaling is abnormal in lesional psoriatic skin, RXRalpha expression is mainly confined to differentiated keratinocytes.