JPH0769904A - Leukocyte-removing filter - Google Patents

Abstract

PURPOSE:To prepare a leukocyte removing filter capable of removing leukocyte in blood at a high ratio without lowering the blood flow rate. CONSTITUTION:This leukocyte removing filter is composed of a three-layer fiber aggregate packed in a housing. The 1st layer to collect coagulum particles larger than leukocyte and prevent the clogging of the 2nd layer has a fiber diameter of 10-20mum and a bulk density of 0.15-0.2g/cm<3>, the 2nd layer to collect small particles comparable to leukocyte has a fiber diameter of 4-10mum and a bulk density of 0.07-0.17g/cm<3> and the 3rd layer to remove leukocyte at a high ratio and recover erythrocyte has a fiber diameter of 1-4mum and a bulk density of 0.05-0.15g/cm<3>. A fiber aggregate having an average pore diameter of 80-300mum (preferably a mesh of 30-500mum thick) is inserted as a substrate between the 1st layer and the 2nd layer. The substrate inserted between the 1st and the 2nd layers disperses the blood flow direction in the 1st layer and enables the maintenance of the blood flow rate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a filter for removing leukocytes in blood and body fluids.

[0002]

2. Description of the Related Art In the treatment of frequent transfusion patients, it is widely known that leukocyte-removed blood products are transfused to improve non-hemolytic fever reactions that show symptoms such as fever, chills, and scars. Has been.

Normally, there are 10 ⁹ white blood cells in 400 cc of blood, and patients transfused with the blood have anti-H
It produces LA antibody and exhibits a non-hemolytic fever reaction. When 99.9% of leukocytes in the blood are removed, the leukocyte count is lowered to the level of 10 ^{6 in the} above unit dose, and the non-hemolytic fever reaction is prevented.

Further, as it has been revealed that the side effect after blood transfusion is due to the alloimmune reaction caused by leukocytes in blood products, leukocytes in the blood are removed by 99.9% or more in order to prevent the induction of alloimmune. Is required.

There are two methods for removing leukocytes: a method by centrifugation utilizing the difference in specific gravity of blood components and a method using a leukocyte removal filter. Since a high leukocyte removal rate can be obtained by a simple operation, the leukocyte removal filter is available. The use of is widespread.

The leukocyte-removing filter is one in which a housing is filled with an ultrafine fiber nonwoven fabric made of a hydrophobic fiber such as polyester or a porous body, and leukocytes are removed by being trapped and adsorbed on the fiber surface.

In order to remove leukocytes at a high rate, it is preferable to increase the fiber surface area in the fiber assembly, and if the volume of the non-woven fabric is the same, the non-woven fabric having a smaller fiber diameter has a smaller fiber surface area. In a non-woven fabric having the same fiber diameter, the larger the bulk density and the smaller the fiber spacing, the larger the fiber surface area.

Blood products contain blood cell components such as red blood cells, white blood cells, and platelets, plasma, and agglomerates. First, in order to reduce clogging of the ultrafine fiber nonwoven fabric due to the agglomerates, the agglomerates with a large diameter are first A two-layer filter has been proposed in which leukocytes are removed by a filter layer and then white blood cells are removed by a main filter layer. This aims to reduce the clogging of the main filter by arranging the fiber aggregate having a large fiber diameter in the upper layer of the fiber aggregate having a small fiber diameter, but the aggregate of 10 to 20 μm having the same size as the white blood cells. It is not enough to remove the erythrocyte, and blood having a high Ht value has a defect that the filtration time becomes long.

In addition, 3 to 4 in which the prefilter layer is reinforced
It has been proposed to prevent the main filter layer from being clogged with a layered structure (Japanese Patent Laid-Open No. 1-236064). This is because the range of the fiber diameter and the fiber interval of each layer is limited, and the larger diameter of the agglomerate is captured, and the frequency of closing the main filter layer is less than that of the two-layer structure. Since there is no change in that it gradually becomes clogged, it has not been technically solved yet.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a filter for efficiently removing leukocytes in blood by improving the problems of the leukocyte removal filter using a fiber assembly composed of hydrophobic fibers. To aim.

[0011]

SUMMARY OF THE INVENTION The present invention is a fiber assembly filled in a housing, the assembly comprising:
The first layer has a fiber diameter of 10 to 20 μm and a bulk density of 0.15 to 0.
25 g / cubic centimeter, the second layer has a fiber diameter of 4 to 10 μm and a bulk density of 0.07 to 0.17 g / cubic centimeter, and the third layer has a fiber diameter of 1 to 4 μm and a bulk density of 0.05 to 0.15 g / A gist of a leukocyte-removing filter characterized in that a fiber assembly having a cubic centimeter and an average pore diameter of 80 to 300 μm is arranged as a support between the first layer and the second layer.

In the present invention, the fiber assembly is an assembly in which fibers are entangled with each other and hold a large number of continuous shared spaces, and examples thereof include forms such as porous bodies, non-woven fabrics, woven fabrics and meshes.

It is preferable to use hydrophobic fibers such as polyester, polypropylene, polyethylene and polytetrafluoroethylene for the fiber assembly.

In use, the direction of flowing blood through the leukocyte removal filter made according to the present invention is the first in the housing.
Flow from the layer fiber assembly toward the second and third layer fiber assemblies.

The fiber diameter and bulk density of the first layer in the present invention are determined to prevent clogging of the second layer and capture aggregates larger than white blood cells.

The fiber diameter and bulk density of the second layer in the present invention are determined in order to capture microaggregates of the same size as white blood cells.

The fiber diameter and bulk density of the third layer in the present invention are such that the fiber is easy to manufacture, the red blood cells are prevented from being clogged, and the average interfiber spacing when passing concentrated red blood cells is maintained. It was decided. White blood cells can be collected at a high rate by removing white blood cells in the third layer.

In the present invention, the above-mentioned three-layer fiber assembly is used to remove aggregates and leukocytes in blood at a high rate.

However, in order to capture and remove the agglomerates on the fiber surface and block the fiber space,
It was found that as the agglomerates were removed in large numbers, the first layer gradually became clogged, eventually reducing the flow rate of the entire layer.

Therefore, as a result of studying a method which does not reduce the flow rate of the entire layer even if a clogging point occurs in the first layer,
By disposing the support between the first layer and the second layer, the effect of less clogging and less decrease in the flow rate was obtained.

The conventional method has the effect of capturing and removing the aggregates stepwise while keeping the blood flow direction constant, but has the drawback that the clogging points converge because the blood flow direction is not dispersed. First by arranging the support
It was possible to maintain the blood flow by distributing the blood flow direction of the layers.

When a support is arranged between the second layer and the third layer, there is no effect of dispersing the blood flow direction in the first layer, and the second layer is used.
It is not preferable because the layer is clogged.

In the present invention, the support means the first layer and the second layer.
It refers to a thin filter layer having a thickness of 30 to 500 μm that separates layers, and a mesh-like form is preferably used.

In the present invention, the average pore size means the size of the space formed by fibers intersecting at right angles.

The average pore size is measured as follows. TYR
Fine particles of various sizes (diameters) are prepared using a standard mesh manufactured by ER. The particulate material need not be specified, but may be polyethylene or polyvinyl chloride. Next, the fiber aggregate in the housing measures the maximum diameter of the fine particles when passing the fine particles and the minimum diameter of the fine particles when not passing the fine particles. The average value of the maximum diameter and the minimum diameter of the above measurement is defined as the average pore diameter of the fiber assembly.

In the present invention, the average pore size of the support disposed between the first layer and the second layer is in the range of 80 to 300 μm. If it is less than 80 μm, the thickness of the support becomes small, and it is difficult to maintain the blood flow rate.
When it exceeds m, the thickness of the support becomes large and a drift occurs, which is not preferable.

[0027]

The leukocyte removal filter of the present invention has the effect of removing leukocytes in blood at a high rate without losing the blood flow rate.

[0028]

EXAMPLES The effects of the present invention will be shown by examples. In the following examples and comparative examples, leukocyte removal rate and red blood cell recovery rate, which are evaluation items, were calculated by the following formula. Leukocyte removal rate = {1- (white blood cell count after filtration) / (white blood cell count before filtration)} × 100 Red blood cell recovery rate = (Ht value after filtration) / (Ht value before filtration) ×
100

In order to fill the filter, a polyolefin housing having a filtration area of 40 cm 2 and a capacity of 30 cc was prepared.

As a filter material, a fiber diameter of 13 μm
And a polyester non-woven fabric having a bulk density of 0.2 g / cubic centimeter (hereinafter referred to as A) and a polyester non-woven fabric having a fiber diameter of 5.5 μm and a bulk density of 0.12 g / cubic centimeter (hereinafter referred to as B).
Say. ), The fiber diameter is 1.8 μm, and the bulk density is 0.10 g /
Cubic centimeter polyester non-woven fabric (hereinafter referred to as C) is further used as a support, having an average pore diameter of 96 μm and a thickness of 18
A polyester mesh of 0 μm (hereinafter referred to as “D”) was prepared.

As an example, the housing is filled in the order of A-D-B-C, 1 unit of concentrated red blood cells derived from whole blood 400 on the 10th day after blood collection is filled without priming, and the head difference is 1
The filtration was performed according to the filling order of the nonwoven fabric at m. As a result of measuring the white blood cell count and Ht value before and after filtration, the white blood cell removal rate was 9%.
It was 9.9% and the red blood cell recovery rate was 97%. In addition, the time from immediately after filling the blood until the blood bag became empty was measured as the filtration time, and was 6 minutes 11 seconds.

As Comparative Example 1, A- was used without using a support.
The housing was filled in the order of B-C, and the same test as the example was performed. As a result, the leukocyte removal rate was 99.8%, the red blood cell recovery rate was 92%, and the filtration time was 18 minutes and 35 seconds.

As Comparative Example 2, the housing was filled in the order of D-A-B-C, and the same test as that of the example was conducted. As a result, the leukocyte removal rate was 99.9% and the red blood cell recovery rate was 91.
%, The filtration time was 10 minutes 49 seconds.

As Comparative Example 3, the housing was filled in the order of A-B-D-C, and the same test as that of the embodiment was conducted. As a result, the leukocyte removal rate was 99.5% and the red blood cell recovery rate was 85.
%, The filtration time was 25 minutes and 13 seconds.

As can be seen from the above results, in comparison with the comparative example, the example has the shortest filtration time and excellent leukocyte removal rate / erythrocyte recovery rate.

Claims (1)

[Claims] 1. A fiber aggregate filled in a housing, wherein the first layer has a fiber diameter of 10 to 20 μm, a bulk density of 0.15 to 0.25 g / cubic centimeter, and a second layer of fibers. The diameter is 4 to 10 μm, the bulk density is 0.07 to 0.17 g / cubic centimeter, and the third layer has a fiber diameter of 1 to 4 μm and a bulk density of 0.0.
A leukocyte-removing filter, which is 5 to 0.15 g / cm 3 and has a fiber assembly having an average pore diameter of 80 to 300 μm as a support between the first layer and the second layer.