Isotopic organ transplantation has become the best method for treating various end-stage diseases. Transplant immunological research has shown that the frequency and severity of acute rejection reactions in the early post-transplant period are potential important risk factors for chronic graft dysfunction. However, the mechanisms of acute rejection occurrence and development have not yet been fully elucidated, and there is still a lack of other sensitive, accurate, reliable, and convenient indicators for detecting and intervening with transplant rejection at an early stage. This project aims to observe the dynamic changes in the expression levels of peripheral blood lymphocytes CD15s, CD44, CD28, as well as the commonly used clinical monitoring indicators CD4/CD8 and MHC-DR during the process of acute rejection reaction, and their relationship with rejection through a comparative study of 20 pig pancreatic transplant rejection models. The research content includes establishing a pig pancreatic transplant rejection model; The study used flow cytometry to observe the changes in CD15s, CD44, CD28 and CD4/CD8, MHC-DR expression on peripheral blood T lymphocytes of model animals; pathological examination was performed on grafts at different periods after transplantation rejection surgery (rejection reaction process) to assess acute rejection grades, and the relationship between these expressions and the severity of acute rejection was analyzed. The conclusion of this study is that monitoring the surface markers CD15s, CD44, CD28 on peripheral blood lymphocytes has certain application value in recipient immune status monitoring and rejection diagnosis, which is superior to traditional single detection of CD4/CD8 ratio; it also has significance in predicting the severity and outcome of acute rejection. The simultaneous monitoring of the positive rate and fluorescence intensity of adhesion molecules on the membrane surface of various lymphocyte subsets is conducive to providing more information about changes in lymphocyte status. Experts have discussed that the overall research level of this project has reached a leading domestic level.