ObjectiveTo learn further the local immunity changes of rectal cancer after neoadjuvant therapy and improve the cognition of this project. MethodsSixty cases of paraffin-embedded sections of the excised specimen from the two groups of middle and low rectal cancer patients, with (therapy group) or without (control group) neoadjuvant therapy, were studied respectively. Tumor infiltrating lymphocytes (TIL) in the two groups were counted under microscope, and also, dendritic cells (DC) were counted and morphology and distribution of the DCs were recorded through immunohistochemistry stain with monoclonal antibody, S-100. ResultsTILs and DCs in the two groups mainly assembled in the pericancerous tissues. The positive rate of TIL in therapy group was 75.00% (45/60) and 90.00% (54/60) in control group (χ2=10.58, P=0.014). S-100 positive DCs were (36.85±11.17)/HPF versus (26.50±7.68)/HPF in the therapy group and control group, respectively (P=0.001). ConclusionNeoadjuvant therapy for rectal cancer can influence the local tumor immunity enviroment by reducing TILs and increasing DCs.