The present application provides a method of upregulating an expression of immumodulatory cells in vitro comprising treating the immumodulatory cells with IL-25 to increase an expression of PD-L1. The present application also provides a method for treatment of immune disorders by the aforementioned methods. The present application also provides a method to suppress an expression of immumodulatory cells comprising suppressing an expression of PD-L1. The immumodulatory cells can be human monocytes or hMSCs. The present application further provides a method for treatment of immune-evasive diseases by using the aforementioned method to suppress an expression of immumodulatory cells.