The effect of previous blood transfusion on lymphocyte subsets and natural killer cell function in patients with...

To elucidate the possible influence of previous blood transfusion on immune functions, the transfusion history of 153 patients admitted to hospital for elective colorectal surgery was correlated with lymphocyte subsets and natural killer (NK) cell function. The subsets determined were CD2, CD3, CD4, CD8, CD16, CD20, CD56, CD57 and HLA-DR-positive. The NK cell function was determined by measuring the killing capacity against cFDA-labelled K562 target cells monitored via a flow-cytometer. We found that 42 patients (27%) had been transfused before surgery, of these 13 had been transfused less than 30 days before surgery and 29 (19%) transfused more than 30 days before (median 10 years, range 0.1-37 years). In transfused patients, we found a significantly reduced number of B lymphocytes (CD20; p = 0.01), a reduction in HLA-DR-positive cells (p = 0.02) and a just significant reduction of NK cell function in transfused compared to nontransfused patients. The reduction in NK cell function is marginal and the NK cell function is within normal range, and probably without clinical significance. Reduction in NK cell function has been described before, whereas the reduction in B cells has not been reported earlier. The results may suggest an impaired humoral immunity and a minor reduction in cellular immunity in patients following blood transfusion.