Abstract: An object of the present invention is to provide a separation system and a separation material for efficiently separating white blood cells or mononuclear cells from a biological fluid containing blood cell components. White blood cells or mononuclear cells can be efficiently separated by contacting a biological fluid containing blood cell components with a separation material having an average fiber diameter of at least 2.0 ?m but not more than 6.0 ?m and an air permeability coefficient M of at least 6.2 but not more than 35 to capture white blood cells on the separation material, and recovering the captured white blood cells or mononuclear cells using a detachment solution.

Abstract: The present invention aims to provide a mononuclear cell preparation material capable of improving the mononuclear cell recovery while reducing granulocyte contamination, and a mononuclear cell preparation method which improves the mononuclear cell recovery. Provided is a mononuclear cell preparation material for removing granulocytes from blood to prepare mononuclear cells, which includes a nonwoven fabric made of a polyamide resin. Also provided is a method for preparing mononuclear cells using a device with the mononuclear cell preparation material packed in a container, the method including the steps of: (A) passing blood through the mononuclear cell preparation device from an inlet side to an outlet side of the device, thereby capturing granulocytes in the device; and (B) passing a washing solution through the mononuclear cell preparation device from the inlet side to the outlet side of the device, thereby recovering mononuclear cells remaining in the device.

Abstract: An object of the present invention is to provide a separation system and a separation material for efficiently separating white blood cells or mononuclear cells from a biological fluid containing blood cell components. White blood cells or mononuclear cells can be efficiently separated by contacting a biological fluid containing blood cell components with a separation material having an average fiber diameter of at least 2.0 ?m but not more than 6.0 ?m and an air permeability coefficient M of at least 6.2 but not more than 35 to capture white blood cells on the separation material, and recovering the captured white blood cells or mononuclear cells using a detachment solution.