Reduction of bioactive substances in stored donor blood: prestorage versusbedside leucofiltration

Leucocyte filtration has been suggested to improve transfusion products. We studied the effect of prestorage versus bedside leucofiltration on reducti on of bioactive substances and leucocyte content in donor blood. Forty-five units of whole blood from healthy blood donors were studied. Of these unit s, 9 were stored under standard conditions for 35 d, 9 were leucofiltered a fter donation and then stored for 35 d, and 3 x 9 units were stored for 7, 21 and 35 d, respectively, before leucofiltration. Samples were collected f rom blood units immediately after donation, and before and after leucofiltr ation, and analysed by ELISA and RIA methods for extracellular content of m yeloperoxidase (MPO), eosinophil cationic protein (ECP), histamine (HIS) an d plasminogen activator inhibitor-1 (PAI-1). Leucocyte content was counted in all samples. In non-filtered blood extracellular MPG, ECP, HIS and PAI-1 were accumulated in a storage time-dependent manner, while prestorage leuc ofiltration prevented this accumulation. Leucofiltration after storage for 7, 21 or 35 d did not significantly reduce the accumulated bioactive substa nces, which were similar to levels in non-filtered blood stored for the sam e period of time. Prestorage and bedside leucofiltration on day 7 reduced t he leucocyte content to less than 0.5 x 10(6)/L, whereas the median content in blood stored for 21 or 35 d was only reduced to 32.0 and 52.2 x 10(6)/L , respectively. Prestorage leucofiltration may thus be advantageous to beds ide leucofiltration.