Leukocyte filtration does not affect lymphocyte subpopulations and NK cell function in recipients of blood transfusions.

Background and objectives: The possible immunosuppressive action of blood transfusion has aroused great interest recently, particularly with respect to its effects on tumor growth and recurrence rate of malignant disease. Materials and methods: The effect of blood transfusion on lymphocyte subpopulations and NK cell function preoperatively and 6 months postoperatively was studied in 129 patients treated with elective surgery for colorectal malignancy. Forty-two patients (33%) received blood transfusions, 21 of them randomly allocated to receive leukocyte-depleted blood products. Investigation was by means of conventional laboratory methods. Results: In 21 patients receiving a median of 3 units of non-leukocyte-depleted blood products (NLD), a significant reduction in CD4+ lymphocytes (44% vs. 40%, p<0.01) occurred. In contrast, no significant changes in CD4+ lymphocytes were observed in the 21 patients transfused with leukocyte-depleted blood products (LD). However, with respect to lymphocyte subpopulations and NK cell function, differences between the NLD and LD groups were not significant. There was a marginal decrease in HLA-DR+ lymphocytes in the NLD patients without a history of previous transfusion. Conclusions: There seems to be no major change in lymphocyte subpopulations and NK cell function 6 months after blood transfusion. Thus we cannot confirm our previous findings of a reduced number of CD20+ cells after blood transfusion.