How do the active ingredients in Dovobet ointment work in psoriasis?

In Dovobet ointment, calcipotriol is proposed, from in vitro data, to promote keratinocyte differentiation and suppress proliferation, while betamethasone dipropionate has anti-inflammatory, anti-itch, vasoconstrictive and immunosuppressive effects without curing psoriasis; its anti-inflammatory mechanism is unclear.