Given that PGD2 production was increased in the skin of mPGES-1−/− mice after the induction of psoriasis, we confirmed the effect of PGD2 in IMQ-induced psoriasis pathology under the condition of mPGES-1 deficiency using antagonists specific for each PGD2 receptor (DP) subtype DP1 and DP2. Here, PTGDR is linked to psoriasis.