Cell removal method, cell removal system, and white blood cell removal method

A cell removal system that is mountable on a centrifugal separator and removes predetermined cells from a body fluid, comprising:

• a body fluid bag that receives a body fluid, the body fluid bag having a first end portion and a second end portion, wherein the first end portion and the second end portion are provided at opposing ends of the body fluid bag;
• a first body fluid component bag that receives a first body fluid component having a relatively high cell concentration in the body fluid;
• a second body fluid component bag that receives a second body fluid component having a relatively low cell concentration in the body fluid;
• a first channel that connects the first body fluid component bag and the body fluid bag;
• a second channel that connects the second body fluid component bag and the body fluid bag;
• a filter that is provided in the first channel and removes predetermined cells from a body fluid component passing through the channel;
• a first on-off valve that opens and closes the first channel, and that is connected to the first channel at a position closer to the body fluid bag than the filter in the first channel;
• a second on-off valve that opens and closes the second channel;
• a preservation liquid supply circuit that is connected to the first channel at a position closer to the body fluid bag than the filter and the first on-off valve, and that supplies a preservation liquid for preserving the first body fluid component;
• and
• a blood collection channel configured to receive blood collected from a human body,
• the first channel and the second channel being connected to the first end portion of the body fluid bag, the first end portion configured to be mounted on the centrifugal separator on a side of a direction of a centrifugal force generated by the centrifugal separator, and wherein
• the blood collection channel is connected to the second end portion of the body fluid bag, and the second channel does not have any filter.