- Lymphapheresis (at the beginning of the study and at 12 months) - This is a procedure for collecting large quantities of white blood cells. A needle is placed in a vein in the arm. Blood flows from the vein through a plastic tube (catheter) into a machine that spins the blood, separating it into its components. The white blood cells (lymphocytes) are removed, and the rest of the blood-plasma, red cells and platelets-is returned to the body through a second needle placed in the other arm.