Methods (300), devices, and systems of processing blood are described. The method (300) comprises the steps of: obtaining (312) blood from a patient coupled to a single blood processing device to form a closed loop between the patient and the blood processing device; collecting (314) bulk mononuclear blood cells from the blood by leukapheresis implemented using the blood processing device in the closed loop; and enriching (316) concurrently target cells separated from non-target cells in the bulk mononuclear blood cells using the blood processing device in the closed loop.