CD4 and alkaline phosphatase measurement: Thus, we first observed whether peripheral blood lymphocyte subsets (i.e., CD3+Tlymphocytes, CD4+Tlymphocytes, CD8+cytotoxic T lymphocytes, CD16+CD56+ natural killer cells, CD19+Blymphocytes, and CD4+/CD8+ T lymphocytes) at admission changed in the early stage of AP in order to research the occurrence of AP.