A tangential flow filtration device for the preparation of a leukocyte-enriched population of cells, selectively removing blood components such as plasma, platelets, and erythrocytes, comprising: a collecting unit (1) having a cylindrical cross-flow chamber (3) and a filter chamber (4) separated by a filter (5) arranged between them, where the filter (5) communicates the fluid from the cross flow chamber (3) with the filter chamber (4)； the diameter of the filter (5) is substantially equal to the diameter of the cross flow chamber (3)； the cylindrical cross flow chamber (3) having an inlet (6) and an outlet (7)； the inlet (6) is arranged adjacent to the retentate surface of the filter (5) to introduce a sample of leukocyte-containing blood components into the cross flow chamber (3) and parallel to the retentate surface of the filter (5) ； and the outlet (7) is adjacent to and perpendicular to the center of the filter retaining surface (5)； the filter chamber (4) having an outlet (8)； a recovery unit (2) comprising a cover (9), an inlet (10) and an outlet (11), the cross flow chamber (3) and the recovery unit (2) being interconnected in a loop, where the inlet of the cross flow chamber (6) communicates the fluid with the outlet of the recovery unit (11), and the outlet of the cross flow chamber (7) communicates the fluid with the inlet of the recovery unit (10)； a pump (14) for pumping fluid into the cross flow chamber (3) through the inlet (6), and configured to introduce fluid into the cylindrical cross flow chamber at an input rate between 5 and 100 times higher to the filtration rate； where this arrangement causes the fluid from the cross flow chamber (3) to flow spirally towards the center of the filter (5) creating a swirling movement of the fluid, the filter (5) having an average pore size that It ranges from 3 to 8 microns, so that the flow of the sample through the filter (5) enriches the sample of blood components in leukocytes, and the collecting unit (1)
