Leukocyte-removing filter device and system and method of using thereof

A leukocyte-removing system comprising:

• a leukocyte-removing filter device comprising:
• (a) a flat casing comprising opposite flat main walls fluid-tightly connected by a side wall structure to define an internal space of said casing, each main wall vertically extending and having a width and a height, said side wall structure having a width defined by a distance between said opposite flat main walls, wherein said casing has a top and a bottom portion which are spaced apart vertically of said casing, and wherein the width or height of each main wall, whichever is shorter, is at least two times the width of the side wall structure,
• said top portion having an inlet for blood and an outlet for leukocyte-removed blood, and
• said top portion vertically extending from a top end of said casing over a length one-third or less the entire vertical length of the casing as measured from the top end of the casing;
• and
• (b) a filter medium comprising at least one filter material sheet extending within said internal space of the casing along said flat main walls to partition said internal space into an inlet-side chamber communicating with said inlet and an outlet-side chamber communicating with said outlet, said outlet-side chamber not discontinuously varying in horizontal cross-sectional area more than 10% over the entire inner space of the outlet-side chamber from its inner bottom portion to its inner uppermost portion,
• inlet connecting means fluid-tightly connected to the inlet for aseptically connecting a part preceding the leukocyte-removing filter device to said inlet,
• at least one satellite bag, and
• outlet connecting means for fluid-tightly directly connecting said outlet of the leukocyte-removing filter device to said at least one satellite bag, said outlet connecting means comprising a tube,
• wherein said leukocyte-removing system is entirely in an aseptic state.

A method for removing leukocytes from blood, which comprises the steps of:

• (1) providing a leukocyte-removing filter device comprising:
• (a) a flat casing comprising opposite flat main walls fluid-tightly connected by a side wall structure to define an internal space of said casing, each main wall vertically extending and having a width and a height, said side wall structure having a width defined by a distance between said opposite flat main walls, wherein said casing has a top and a bottom portion which are shaped apart vertically of said casing, and wherein the width or height of each main wall, whichever is shorter, is at least two times the width of the side wall structure,
• said top portion having an inlet for blood and an outlet for leukocyte-removed blood, and
• said top portion vertically extending from a top end of said casing over a length one-third or less the entire vertical length of the casing as measured from the top end of the casing, and
• (b) a filter medium comprising at least one filter material sheet extending within said internal space of the casing along said flat main walls to partition said internal space into an inlet-side chamber communicating with said inlet and an outlet-side chamber communicating with said outlet, said outlet-side chamber not discontinuously varying in horizontal cross-sectional area more than 10% over the entire inner space of the outlet-side chamber from its inner bottom portion to its inner uppermost portion;
• (2) allowing blood to flow into the inlet of said filter device and pass through said filter medium contained in said filter device to thereby remove leukocytes from the blood, and discharging leukocyte-removed blood from the outlet of said filter device.

A method for removing leukocytes from blood, which comprises the steps of:

• (1) providing at least one leukocyte-removing system comprising:
• (A) a leukocyte-removing filter device comprising:
• (a) a flat casing comprising opposite flat main walls fluid-tightly connected to a side wall structure to define an internal space of said casing, each main wall vertically extending and having a width and a height, said side wall structure having a width defined by a distance between said opposite flat main walls, wherein said casing has a top and a bottom portion which are spaced apart vertically of said casing, and wherein the width or height of each main wall, whichever is shorter, is at least two times the width of the side wall structure,
• said top portion having an inlet for blood and an outlet for leukocyte-removed blood, and
• said top portion vertically extending from a top end of said casing over a length one-third or less the entire vertical length of the casing as measured from the top end of the casing, and
• (b) a filter medium comprising at least one filter material sheet extending within said internal space of the casing along said flat main walls to partition said internal space into an inlet-side chamber communicating with said inlet and an outlet-side chamber communicating with said outlet, said outlet-side chamber not discontinuously varying in horizontal cross-sectional area more than 10% over the entire inner space of the outlet-side chamber from its inner bottom portion to its inner uppermost portion,
• (B) inlet connecting means fluid-tightly connected to the inlet for aseptically connecting a part preceding the leukocyte-removing filter device to said inlet,
• (C) at least one satellite bag, and
• (D) outlet connecting means for fluid-tightly directly connecting said outlet of the leukocyte-removing filter device to said at least one satellite bag, said outlet connecting means comprising a tube;
• (2) allowing blood to flow into the inlet of said filter device through said inlet connecting means,and pass through said filter medium contained in said filter device to thereby remove leukocytes from the blood, and discharging leukocyte-removed blood from the outlet of said filter device;
• and
• (3) transferring leukocyte-removed blood to said at least one satellite bag through said outlet connecting means.