Method for separating a volume of whole blood into at least three components

1. Method for separating a volume of whole blood contained in a separation bag into at least three components, the method comprising:

centrifuging the separation bag so as to separate therein a first inner layer comprising plasma, a second intermediate layer comprising platelets, a third intermediate layer comprising lymphocytes, monocytes and granulocytes and a fourth outer layer comprising red blood cells, wherein at least the third and fourth layers partially overlap;

transferring, into a plasma component bag connected to the separation bag, a plasma component substantially comprising a first fraction of the first layer;

transferring, into a platelet component bag connected to the separation bag, a platelet component substantially comprising a fraction of the second layer; and

transferring, into a mononuclear cell component bag connected to the separation bag, a mononuclear cell component comprising at least a fraction of the third layer comprising lymphocytes and monocytes;

after transferring the mononuclear cell component into the mononuclear cell component bag and before transferring the red blood cell component from the separation bag into a red blood cell component bag, transferring a volume of storage solution from the red blood cell component bag into the separation bag, and

after transferring said volume of storage solution into the separation bag, transferring, into a red blood cell component bag connected to the separation bag, a red blood cell component comprising the fourth layer and a fraction of the third layer comprising granulocytes.

2. Method according to claim 1 , further comprising filtering the red blood cell component during the transfer thereof into the red blood cell component bag so as to substantially remove therefrom granulocytes, and residual monocytes and lymphocytes.

3. Method according to claim 1 , wherein transferring the red blood cell component from the separation bag into the red blood cell component bag occurs after stopping centrifuging the separation bag.

4. Method according to claim 1 , wherein the red blood cell component is transferred by gravity from the separation bag into the red blood cell component bag.

5. Method according to claim 1 , wherein the step of transferring the platelet component further comprises transferring into the platelet component bag connected to the separation bag, a platelet component comprising a fraction of the second layer and the fraction of the first layer remaining in the separation bag after the transfer of the plasma component into the plasma component bag.

6. Method according to claim 5 , further comprising mixing the fraction of the first layer and the fraction of the second layer of which the platelet component is comprised so as to suspend platelets in plasma before transferring the platelet component into the platelet component bag.

7. Method according to claim 5 , wherein transferring the platelet component into the platelet component bag comprises using at least two successive flow rates, a first flow rate being faster than a second flow rate.

8. Method according to claim 1 , further comprising stopping centrifuging the separation bag after transferring the mononuclear cell component into the mononuclear cell component bag.

9. Method according to claim 1

wherein the transferring into a plasma component bag comprises:

blocking a fluid communication between the separation bag and the mononuclear cell and platelet bags;

allowing a fluid communication between the separation bag and the plasma component bag;

squeezing the separation bag until red blood cells are detected at a first distance from the axis of rotation so as to transfer, into the plasma component bag, a plasma component comprising a first fraction of the first layer;

wherein the transferring into a platelet component bag comprises:

blocking a fluid communication between the separation bag and the plasma component and mononuclear cell bags;

squeezing the separation bag until platelets are detected at a second distance from the axis of rotation so as to transfer, into the platelet component bag, a platelet component comprising the second intermediate layer; and

wherein the transferring into a mononuclear cell component bag comprises:

blocking a fluid communication between the separation bag and the plasma component and platelet bags;

allowing a fluid communication between the separation bag and the mononuclear cell component bag; and

squeezing the separation bag so as to transfer, into the mononuclear cell component bag, a mononuclear cell component comprising at least a fraction of the third layer comprising lymphocytes and monocytes.

10. Method according to claim 9 , wherein the mononuclear cell component transferred into the mononuclear cell component bag has a predetermined volume.

11. Method according to claim 10 , wherein the volume of whole blood is about 450 ml and the volume of the mononuclear cell component is comprised between about 10 ml and about 15 ml.

12. Method according to claim 10 , wherein the volume of whole blood is about 450 ml and the volume of the mononuclear cell component is comprised between about 50 ml and about 60 ml.

13. Method according to claim 9 further comprising, after transferring the mononuclear cell component into the mononuclear cell component bag, stopping centrifuging the separation bag.

14. Method according to claim 9 further comprising, after squeezing the separation bag so as to transfer the plasma component into the plasma component bag and before squeezing the separation bag so as to transfer the platelet component into the platelet component bag:

mixing the second layer and a second fraction of the first layer remaining in the separation bag so as to prepare a platelet component comprising platelets of the second layer suspended in the second fraction of the first layer.

15. Method according to claim 14 , wherein mixing the second layer and a second fraction of the first layer remaining in the separation bag so as to prepare a platelet component comprises:

decreasing the rotation speed from the first rotation speed to a second rotation speed so as to mix the second fraction of the first layer, the second layer, the third layer and a fraction of the fourth layer; and

increasing the rotation speed from the second rotation speed to a third rotation speed so as to separate the platelet component from the third layer and the fourth layer, the third rotation speed being lower than the first rotation speed.

16. Method according to claim 14 , wherein squeezing the separation bag so as to transfer the platelet component into the platelet component bag comprises:

squeezing the separation bag so as to transfer the platelet component at a first flow rate until red blood cells are detected at a second distance from the axis of rotation, the second distance being smaller than the first distance;

squeezing the separation bag so as to transfer the platelet component using at least a second flow rate lower that the first flow rate, following the detection of red blood cells at the second distance from the axis of rotation; and

stopping squeezing the separation bag following the detection of red blood cells at a third distance from the axis of rotation, the third distance being smaller than the second distance.

17. Method according to claim 9 , further comprising filtering the red blood cell component during the transfer thereof into the red blood cell component bag so as to substantially remove therefrom granulocytes, and residual monocytes and lymphocytes.

18. Method according to claim 9 , wherein transferring the red blood cell component from the separation bag into the red blood cell component bag occurs after stopping centrifuging the separation bag.

19. Method according to claim 9 , wherein the red blood cell component is transferred by gravity from the separation bag into the red blood cell component bag.