 - Two sessions of lymphapheresis, one at the beginning of the study and one a year later-to collect lymphocytes. For this procedure, whole blood is drawn through a needle in an arm vein, much like donating a unit of blood. The blood then flows through a catheter plastic tube into a cell separating machine, where the white blood cells are extracted and removed. The red cells and plasma are then returned to the body through a needle in the other arm. The procedure takes about 60 to 90 minutes. 