Objective To investigate the changes of CD4+,CD8+and B cells in peripheral blood of breast cancer patients detected before and after surgery and following chemotherapy and the relationship with clinical prognosis.Methods Seventy-nine pa-tients with breast cancer who were admitted for treatment in the Department of General Surgery,Shanghai Minhang Central Hospital from July 2015 to March 2017 were enrolled for the study.T cell and B cell counts were detected by flow cytometry in the peripheral blood of breast cancer patients and benign breast cancer patients,and differences were analyzed between the patients of the 2 groups.Then,the relationship between T cell and B cell counts detected in the patients before and after surgery and following chemotherapy and those pa -tients with different TNM staging and molecular typing.Results There were statistical differences in CD4+cell counts and TNM stag-ing between the patients with malignant and benign tumors(P<0.05;P<0.05).There were also statistical differences in CD8+cell counts,when comparisons were made between the patients with malignant and benign tumors, before and after surgery and following chemotherapy,and between different age stages(P<0.05;P<0.05).After chemotherapy, there were statistical differences between different TNM stages(P=0.001)and molecular types(P =0.011).Statistical differences could also be seen in B cells between malignant and benign tumors,between before and after chemotherapy as well as between different age stages(P<0.05;P<0.05;P<0.05).After surgery,statistical differences could also be noted between different TNM stages(P =0.026)and molecular types(P =0.022).CD8+and B cells might be prognostic factors, however, the levels of CD8+and B cells were not necessarily independent predictors of survival after breast cancer treatment.Conclusion The levels of B cells, CD4+and CD8+in peripheral blood have a certain value for the diagnosis and prognosis of breast cancer patients,for this reason,it is worth further research and may promise fu-ture clinical application.