Blood processing systems and methods for collecting mono nuclear cells

A blood separation system comprising

• a chamber for rotation about a rotational axis to separate whole blood into red blood cells, a plasma constituent carrying platelets, and an interface carrying mono nuclear cells between the red blood cells and plasma constituent, the chamber comprising
• first and second spaced apart walls forming a separation zone having a low-G side located closer to the rotational axis than the other, high-G side, the separation zone including an inlet region where whole blood enters the separation zone to begin separation into red blood cells toward the high-G side and the plasma constituent toward the low-G side and a second region spaced from the inlet region,
• a first port communicating with the low-G side of the inlet region for collecting the plasma constituent in the inlet region of the separation zone,
• a second port communicating with the high-G side of the second region for collecting red blood cells in the second region of the separation zone, and
• a controller operable in a first mode to conduct whole blood into the inlet region of the chamber in a first flow direction toward the second region while collecting red blood cells through the second port and plasma constituent through the first port, and in a second mode to back flow red blood cells through the second port into the second region in a second flow direction toward the inlet region while collecting the interface through the first port.

A blood separation system comprising

• a chamber for rotation about a rotational axis to separate whole blood into red blood cells, a plasma constituent carrying platelets, and an interface carrying mono nuclear cells between the red blood cells and plasma constituent, the chamber comprising
• first and second spaced apart walls forming a separation zone having a low-G side located closer to the rotational axis than the other, high-G side, the separation zone including an inlet region having a radial width where whole blood enters the separation zone to begin separation into red blood cells toward the high-G side and the plasma constituent toward the low-G side and a second region having a radial width spaced from the inlet region,
• a first port communicating with the low-G side of the inlet region for collecting the plasma constituent in the inlet region of the separation zone,
• a second port communicating with the high-G side of the second region for collecting red blood cells in the second region of the separation zone,
• the low-g side including a portion extending toward the second region that is displaced radially into the separation zone toward the high-g side, thereby reducing the radial width of the second region compared to the radial width of the inlet region, and
• a controller operable in a first mode to conduct whole blood into the inlet region of the chamber in a first flow direction toward the second region while collecting red blood cells through the second port and plasma constituent through the first port, and in a second mode to back flow red blood cells through the second port into the second region in a second flow direction toward the inlet region while collecting the interface through the first port.

A method for separating mono nuclear cells from whole blood comprising the steps of

• rotating a separation chamber about a rotational axis,
• introducing whole blood into a first region of the chamber during its rotation to separate the whole blood into a plasma constituent, red blood cells, and an interface between the red blood cells and the plasma constituent, the interface containing mono nuclear cells,
• while conveying whole blood into the first region, collecting the plasma constituent in the first region,
• while conveying whole blood into the first region, collecting the red blood cells in a second region of the chamber spaced from the first region,
• thereafter backflowing red blood cells into the second region in a back flow direction toward the first region, and
• while backflowing red blood cells into the second region, collecting the interface in the first region.