Imiquimod-induced psoriasis model: induction protocols, model characterization and factors adversely affecting the model.

Imiquimod-induced psoriasis is widely-employed to study disease pathogenesis and to screen drugs. While the original protocol was published more than a decade ago and has been rigorously used in research since then, a modified protocol was described recently with several advantages including milder systemic manifestations although the disease morphology is highly conserved. Being a toll-like receptor 7 and 8 agonist, IL-23/IL-17 axis predominates in imiquimod-induced psoriasis. In addition, different immunocytes were described to aggravate or supress the disease. This article aims to review the currently available protocols of imiquimod-induced psoriasis in vivo, to characterize the model as described in literature and to define the five important independent factors adversely influencing the model which researchers should pay attention to.