Objective To investigate the changes in counts of T-lymphocyte subsets, natural killer cell (NK cell) and the levels of serum soluble interleukin-2 receptor(sIL-2R) after perioperative allogeneic whole-blood transfusion or erythrocyte suspention (SAG-M blood) blood transfusion. Methods Thirty patients undergoing elective refection for rectal cancer, were randomly allocated to receiving 400 ml of allogeneic whole-blood (n = 15 ) or 400 ml of SAG-M blood (n = 15 ) during perioperative period, respectively. Indirect immunofluorescence technique and enzyme-linked immunosorbent assay were used to determine the counts of T--lymphocyte subsets, NK cells and to detect levels of serum sIL-2R 1 day and 5 day after operation.Results The counts of CD3 +, CD. + and NK cells in both groups decreased significantly after operation (P