Objective:To explore the change of membrane protein composition of red blood cells after the blood being filtered by leukocyte filter.Methods:A total of 400ml blood from 20 healthy donors were equally divided into control group and filtered group according to the paired design.SDS-PAGE electrophoresis was done for the red blood cell membrane protein of both groups.Bandscan protein analysis software was used to analyze the composition of membrane protein.Fluorescence degree of polarization was detected by fluorescence polarization method and membrane flowability was counted.Plasma concentration of free hemoglobin(FHb) was detected weekly.Results:The band Ⅰ

Ⅱ and Ⅶ parotein of membrane skeleton of the filtered group decreased significantly compared with those of the control group(P﹤0.01)

and the fluorescence degree of polarization and microviscosity of the filtered group was higher(P﹤0.01).There was significant difference of plasma FHb between filtered group and control group at each week except week 0

and that of the filted group was higher(P﹤0.01).Conclusion: Leukocyte filter can bring damage to erythrocyte membrane protein composition.Membrane microviscosity and plasma concentration of free hemoglobin increase and membrane flowability decreases.