The purpose of this study is to evaluate the efficacy and safety of Adipose-derived Mesenchymal Stem Cells (AD-MSCs) with moderate to severe psoriasis. Any adverse events related to AD-MSCs infusion will be monitored.The primary outcome is the reduction rate of PASI(Psoriasis Area and Severity Index) and treatment response will be computed from PASI before and after AD-MSCs infusion.