JPH05194243A - Filter material for selecting and capturing leukocyte - Google Patents

Abstract

PURPOSE:To obtain the subject filter material for selecting and capturing leukocytes capable of efficiently removing the leukocytes while suppressing the loss of blood platelets to a small value. CONSTITUTION:The objective filter material for selecting and capturing leukocytes is characterized as fiber or a polymeric porous substance composed of a body part and a surface part and at least the surface part containing a polyethylene oxide chain having basic nitrogen-containing functional groups and 2-15 recurring units.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leukocyte-selective capture filter material which selectively captures leukocytes and allows platelets to pass through. Specifically, leukocyte selection for selectively capturing and removing leukocytes in blood during blood transfusion or extracorporeal circulation, and for selectively capturing and removing leukocytes mixed when adjusting concentrated platelet plasma from blood. Regarding capture filter material.

[0002]

2. Description of the Related Art In recent years, with the progress of immunology and blood transfusion, the concept of component transfusion, in which only the blood components that a patient really needs, is transfused from the conventional whole blood transfusion has been widely used. Various blood products such as concentrated red blood cell (CRC), concentrated platelet liquid (PC), and platelet poor plasma (PPP) used for component transfusion are prepared by separating and fractionating blood obtained by blood donation by centrifugation. It

However, a large number of leukocytes are contained in the blood product fractionated by centrifugation, and the leukocytes mixed therein are relatively slight side effects such as headache, non-hemolytic fever reaction, chills, and nausea. , Alloantigen sensitization, post-transfusion G
Inducing serious side effects such as VHD and virus infection is regarded as a problem, and efforts have been made to remove leukocytes from blood products.

Methods for removing leukocytes from blood products are roughly classified into a centrifugal separation method utilizing a difference in specific gravity of blood components and a filter method using a porous material having ultrafine fibers such as non-woven fabric or continuous pores as a filter material. However, the filter method is widely used because of its high leukocyte removal efficiency, easy operation, and low cost.

However, since most of the above filter materials are made of hydrophobic polymer materials, not only leukocytes but also platelets, which generally have high adhesiveness, are adsorbed and removed. For patients with diseases such as aplastic anemia, thrombocytopenic purpura, and leukemia, it is not possible to transfuse blood products containing a large amount of platelets such as whole blood, concentrated platelets, and red blood cell concentrate to supplement platelets. Although indispensable, if the above filter is used as it is, white blood cells are captured but platelets necessary for the patient are also adsorbed and removed, and if blood is transfused without using a filter, side effects after transfusion are feared. Therefore, it has been earnestly desired to develop a filter that suppresses platelet loss and selectively captures leukocytes.

The adhesion of platelets to the material surface depends on the nature of the material surface. Based on this idea, as a method for suppressing the adhesion of platelets, a method of graft-polymerizing a hydrophilic monomer on the filter material surface or coating a hydrophilic polymer on the filter material surface is known as a known technique. Has been. However, the material thus obtained suppresses the adhesion of platelets, and at the same time, it becomes difficult to remove the adhesion of leukocytes, so that it cannot be used as a filter for the purpose of selectively capturing only leukocytes.

Japanese Unexamined Patent Publication (Kokai) No. 55-129755 discloses a method for collecting leukocytes and lymphocytes containing a small amount of erythrocytes and platelets using a filter having a non-woven fabric surface coated with an antithrombotic material. However, when this filter was used, the loss of platelets was small, but the capturing power of white blood cells was also small, which was not satisfactory.

[0008] WO87 / 05812 discloses a leukocyte selection which uses a filter material in which the surface portion of the fiber contains a nonionic hydrophilic group and a basic nitrogen-containing functional group, has less platelet capture and efficiently captures leukocytes. A removal filter is disclosed. When this filter is used, leukocytes can be selectively captured and removed, and it has the effect of suppressing the capture of platelets, but it is desired to develop a filter that can collect highly adherent platelets in a higher yield. Came.

In order to selectively capture and remove leukocytes and allow platelets to pass through, it is necessary to consider physical and chemical factors of the filter material. The physical factor indicates the physical structure of the filter material, and in a fibrous medium such as a non-woven fabric, the fiber diameter, density, thickness, etc. correspond to this, and in the case of a porous body having continuous pores, the pore diameter, porosity, density , Thickness, etc. correspond to this. Generally, the physical factor of the filter material greatly contributes to the capture of white blood cells, and in order to enhance the capture ability, it is constituted by using ultrafine fibers having a small fiber diameter, increasing the packing density, and decreasing the pore size. It is known. However, when the leukocyte-capturing ability is improved by this method, blood cells are likely to be clogged, which may cause filtration to take a long time, and increase in platelet loss due to adsorption and adhesion of platelets on the filter material. Met. Therefore, if the fiber diameter is increased or the pore size of the porous body is increased in order to suppress the adsorption of platelets to the filter material, the ability of platelets to pass is improved, There was a problem that the capture ability of the Therefore, in order to develop the leukocyte selective trapping filter for the present purpose, it was necessary to chemically modify the surface of the filter material so that leukocytes could be trapped but platelets could pass through. However, as described above, graft polymerization or coating of a hydrophilic monomer or polymer improves the ability of platelets to pass through, but may reduce the ability of capturing leukocytes. Therefore, the chemical treatment of the leukocyte-selective capture filter of the present purpose requires the hydrophilicity that allows the platelets to pass while maintaining the ability to capture leukocytes.
It was necessary to search for a monomer or polymer having a special structure and composition.

When the basic nitrogen-containing functional group is present in at least the peripheral surface portion of the filter material, the surface of the filter material becomes positively charged. When white blood cells and platelets come into contact with the positively charged filter material as described above, the white blood cells and platelets have a negative charge, and thus adhere to the filter material well. However, the leukocyte-selective capture filter material of the present invention must have a property of capturing leukocytes and allowing platelets to pass through.
Therefore, the presence of the basic nitrogen-containing functional group that imparts a positive charge also traps platelets, and cannot be used as the target filter material.

On the other hand, when blood is brought into contact with various polymeric materials, the presence or absence of thrombus and the presence or absence of cell disruption will differ depending on the selection of the material surface. This has not been clarified yet, but it is considered to be due to the magnitude of the complex interaction between the cells contained in blood and the surface of the material used (“medical polymer material”, medical polymer material). Editing Committee edition,
1981). When the material surface is classified from the viewpoint of hydrophilicity and hydrophobicity, in general, a polymer material having a hydrophilic surface has a small interfacial energy between the material surface and blood, and therefore interaction with proteins and blood cells becomes small. It is said that thrombus formation and cell metamorphosis tend to be suppressed (“Biomaterial Science”, Vol. 2, 135,
1982). Therefore, in order to give the filter material the property of passing platelets, the filter material must be hydrophilic, and when the filter material has a hydrophobic surface, a hydrophilic monomer or polymer is grafted to the filter material. It must be introduced by polymerization or coating.

The hydrophilic substance is generally a substance having a functional group having a high affinity for water, such as a hydroxyl group, a carboxyl group, a carbonyl group, an amide group and a sulfonic acid group, but among them, A substance having a polyethylene oxide chain has a property of being well soluble in water because the polyethylene oxide chain exhibits high polarity. Further, it is known that a substance having a polyethylene oxide chain is an excellent blood compatible material having an antithrombotic property. For example, it is known that even if blood is brought into contact with the surface of a polymer material containing polyethylene oxide chains, plasma proteins such as albumin and globumin do not adsorb to the material surface, and the reactivity of platelets is low and thrombus formation is not observed. (Raito Yoshito, Medical Polymer Material, Kyoritsu Shuppan, 1989). Further, when separating the plasma component from the blood, when a porous membrane composed of a substance having a polyethylene oxide chain and acrylonitrile is used, white blood cells, red blood cells, and platelets are not adsorbed on the surface of the porous membrane, so that the plasma component can be collected at high water permeability It is disclosed that proteins that can be separated and that are contained in plasma are not adsorbed on the surface of the porous membrane, so that they can be recovered in high yield (JP-A-61-176359).

When such a substance having a polyethylene oxide chain, which is an excellent blood-compatible material, is introduced into at least the surface portion of the filter material, the above-mentioned low cell adhesion and blood compatibility are imparted, and platelets are filtered. It will pass without adhering to the material surface. However, since white blood cells also pass through at the same time, they cannot be used as a target filter material. As described above, when focusing on capturing leukocytes, platelets are also captured, and when focusing on the passage property of platelets, leukocytes generally pass through at the same time.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a leukocyte selective trapping filter material which suppresses platelet adsorption as much as possible and selectively traps and removes leukocytes in a high yield. Another object of the present invention is to provide a filter material that can be effectively used for platelet transfusion and extracorporeal circulation leukocyte removal therapy for blood, which is used for a leukocyte selective capture filter with low platelet adsorption and efficient removal of leukocytes. ..

[0015]

Means for Solving the Problems The above object is to include a basic nitrogen-containing functional group and a polyethylene oxide chain having a repeating unit of 2 to 15 in at least the peripheral surface portion of a fiber or a polymer porous body having continuous pores. Achieved by.

That is, when both the basic nitrogen-containing functional group and the polyethylene oxide chain are introduced into at least the surface portion of the filter material, surprisingly, the leukocyte-capturing ability is maintained and the platelets hardly stick to each other. It was found that the property of passing through was imparted, and the filter material of the present invention was developed.

That is, the leukocyte selective capture filter material of the present invention is a filter material in which a basic nitrogen-containing functional group and polyethylene oxide chains are contained in at least the peripheral surface portion of a fiber or a polymer porous body having continuous pores. Is.

The content of basic nitrogen atoms in the surface portion of the filter material of the present invention is preferably 0.2 to 4.0% by weight, more preferably 0.3 to 1.5% by weight. The repeating unit of the polyethylene oxide chain is 2 to 15, and the content of the polyethylene oxide chain portion is preferably 2.0 to 22.0% by weight, more preferably 3.0 to 15.0% by weight. If the content of the basic nitrogen-containing functional group is less than 0.2% by weight, the amount of positive charges on the surface of the filter material may be insufficient and the leukocyte capturing ability may be reduced. This is because adhesion to the surface of the filter material may occur, and platelet permeability may be reduced. In addition, the repeating unit of the polyethylene oxide chain exceeds 15, or 2
This is because if it exceeds 2.0% by weight, the leukocyte-capturing ability may decrease, and if it is less than 2.0% by weight, platelets are likely to adhere to the filter material. The content of the basic nitrogen-containing functional group and the content of the polyethylene oxide chain can be measured by, for example, elemental analysis, infrared absorption spectrum or nuclear magnetic resonance spectrum.

Materials having a basic nitrogen-containing functional group that can be introduced into the leukocyte selective capture filter material of the present invention include:
Primary amino group, secondary amino group, tertiary amino group, 4
Examples thereof include a quaternary ammonium group and a nitrogen-containing aromatic ring group such as a pyridyl group and an imidazoyl group. Specific examples thereof include dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate in view of availability and handling. Further, as the material having a polyethylene oxide chain of the present invention, methoxytriethylene glycol,
Methacrylate (repeating unit of polyethylene oxide chain = 3), methoxytetraethylene glycol, methacrylate (repeating unit of polyethylene oxide chain = 4), methoxypentaethylene glycol methacrylate (repeating unit of polyethylene oxide chain =)
5) and the like.

As described above, the filter material of the present invention is characterized in that the basic nitrogen-containing functional group and the polyethylene oxide chain having a repeating unit of 2 to 15 are contained in at least the surface portion of the filter material. ing. In other words, the filter material of the present invention has a body portion and a surface portion separately formed, and only the surface portion is composed of a substance having the basic nitrogen-containing functional group and a polyethylene oxide chain whose repeating unit is 2 to 15. Alternatively, the body portion and the surface portion are integrally formed, or both the body portion and the surface portion, that is, the entire filter material has the basic nitrogen-containing functional group and the repeating unit of 2 units.
It may consist of a substance having a polyethylene oxide chain of ˜15.

Generally, a fibrous medium such as a non-woven fabric or a porous body having continuous pores has a hydrophobic surface, and the basic functional group or polyethylene for the filter material having such a hydrophobic surface is used. The introduction of the oxide chain is carried out by coating the filter material with a copolymer of a polymerizable monomer having a basic nitrogen-containing functional group and a polyethylene oxide chain having a repeating unit of 2 to 15, and This is accomplished by graft polymerizing the filter material.

When a polymer containing a basic nitrogen-containing functional group and a polyethylene oxide chain is introduced on the surface of the material by coating, another polymer having a high blood compatibility and having no basic nitrogen-containing functional group and polyethylene oxide chain is used. It is also preferable to use a copolymer with a monomer. The polymerizable monomer that can be used is not particularly limited, for example,
Examples thereof include acrylic acid derivatives, methacrylic acid derivatives, allyl alcohol, styrene derivatives, acrylonitrile and the like. Among these, acrylic acid or methacrylic acid ester is preferable from the viewpoint of easy availability and handleability, and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and the like are particularly effective for keeping the coating material on the material surface stably. There is also excellent.

The filter material for capturing leukocytes of the present invention is preferably a fibrous medium such as a non-woven fabric or a porous body having continuous pores. It is known that the physical structure of the filter material greatly contributes to the capture of leukocytes, and the selection of the filter material is also an important factor in improving the ability to capture leukocytes. That is, when a fibrous medium such as a non-woven fabric is used as the filter material, the average fiber diameter is 0.3 μm or more and less than 3.0 μm, more preferably 1.0 μm or more,
It is preferably less than 2.0 μm. The packing density when the container is filled with the fibrous medium is 0.1 g / cm ³ or more,
It is preferably less than 0.3 g / cm ³ . Average fiber diameter is 0.3
When it is less than μm and the packing density is 0.3 g / cm ³ or more,
This may cause clogging of blood cells and increase in pressure loss, and if the average fiber diameter is 3.0 μm or more and the packing density is less than 0.1 g / cm ³ , the leukocyte trapping ability may be reduced. Is.

The average fiber diameter in the present invention means a value obtained by the following procedure. That is, a part of the filter element, which is considered to be substantially uniform and constitutes the filter, is sampled and photographed by using a scanning electron microscope or the like. At the time of sampling, the effective filtration cross-sectional area portion of the filter element is divided into squares each having a side of 0.5 to 1 cm, and 3 or more, preferably 5 or more of them are randomly sampled. In order to perform random sampling, for example, after designating an address to each of the above-mentioned sections, a method of using a random number table or the like may be used to select a section of a required number or more. Also, for each sampled section, photograph at least 3 locations, preferably at least 5 locations. The diameters of all the fibers shown in the photograph thus obtained are measured. Here, the diameter means the width of the fiber in the direction perpendicular to the fiber axis. The value obtained by dividing the sum of the measured diameters of all fibers by the number of fibers is defined as the average fiber diameter. However,
If multiple fibers overlap and the width cannot be measured due to the shadow of other fibers, or if multiple fibers have melted and become thick fibers, fibers with significantly different diameters are mixed. If so, these data are deleted. By the above method, the average fiber diameter is calculated from the data of 100 fibers or more, preferably 1000 fibers or more.

When a porous material having continuous pores is used as the filter material, it is desirable that it has an average pore diameter of 3 to 50 μm. If the average pore size is less than 3 μm, blood cells may become clogged, pressure loss may increase, and filtration may take a long time.
This is because if the average pore size exceeds 50 μm, the leukocyte-capturing ability may decrease. Here, the average pore size in the present invention is an average pore size of one porous body before being filled in a container, and is measured by a Coulter porometer 2 (Coulter Electronics and Limited, USA) in an MFP (Mean Flow Pore).
Size).

When the hydrophobic filter material is coated with a polymer having a basic nitrogen-containing functional group and a polyethylene oxide chain, the filter material is soaked in a solution prepared by dissolving the polymer in an appropriate solvent, and then an excess of It can be carried out by a simple operation such as removing the solution from the filter material by squeezing and then drying with hot air. Further, in order to prevent the polymer from falling out of the filter material, heat can be applied to the coated filter material to further enhance the adhesiveness between the filter material and the polymer. In addition, the graft polymerization of a polymerizable monomer having a basic nitrogen-containing functional group and a polyethylene oxide chain having a repeating unit of 2 to 15 onto the filter material is carried out by impregnating the filter material with a solution of the polymerizable monomer, It can be carried out by a simple method of irradiating with radiation and washing with a suitable washing liquid such as water.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples. The leukocyte removal rate and the platelet recovery rate in the following examples are values obtained by the following equations (1) and (2), respectively. The white blood cell concentration before filtration was determined by counting the number of white blood cells in the blood diluted with Turk's solution by an optical microscope, and the white blood cell concentration after filtration was diluted 1.1 times with acridine orange solution. The number of leaked leukocytes was counted for the obtained sample using a fluorescence microscope. The platelet concentration was measured by measuring a sample diluted 250,000 times with an automatic blood cell counter.

[0028]

Example 1 Copolymer of methoxytriethylene glycol methacrylate (hereinafter abbreviated as MTGMA; polyethylene oxide chain repeating unit = 3), 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) and dimethylaminoethyl methacrylate (hereinafter abbreviated as DMAMA). Was synthesized by conventional solution radical polymerization. Polymerization conditions were HEMA, DMAMA and MTGMA in molar fractions of 0.92, 0.03 and 0.05, and the total amount was 1
To the ethanol solution adjusted to be mol / l, 2.2'-azobis (2.4-dimethylpareronitrile) (V-65) was added at 1/200 mol / 1 as an initiator, and 5
The polymerization reaction was carried out at 5 ° C. for 8 hours. The polymer was purified by adding the solution after the reaction to water and precipitating the polymer.

Ten non-woven fabrics (about 0.1 g) having an average fiber diameter of 1.8 μm have an effective filtration cross-sectional area of 21.5 × 21.5.
A non-woven fabric is filled in a container having an inlet and an outlet for blood of 2 mm so that the packing density of the non-woven fabric is 0.2 g / cm ^3, and a 1% ethanol solution of the above polymer is placed in this container so that air does not enter, and nitrogen At a flow rate of 2 l / min for 20 minutes to remove excess polymer solution. 1 at 40 ° C
Vacuum dry the container after coating for 5 hours, then at 4 ° C at 120 ° C to improve the adhesion between polymer and non-woven fabric.
Heat treated for hours. The content of basic nitrogen atoms contained in the surface of the filter material of the obtained leukocyte-selective capture filter was 0.31% by weight, and the content of polyethylene oxide chains was 4.86% by weight.

The above leukocyte selective removal filter was incorporated into a blood circuit, and 0.79 g / mi was obtained using a syringe pump.
31.6 g of concentrated platelet fluid was processed at a constant flow rate of n. The blood volume before and after filtration, the leukocyte concentration, and the platelet concentration were determined, and the leukocyte removal rate and the platelet recovery rate were determined using equations (1) and (2). The leukocyte removal rate was 94.0.
%, And the platelet recovery rate was 92.4%.

[0031]

Example 2 A polymer was synthesized in the same manner as in Example 1 except that the mole fractions of HEMA, DMAMA, and MTGMA were 0.85, 0.10, and 0.05, and the same nonwoven fabric as in Example 1 was used. A white blood cell selective capture filter was obtained by coating the filter material consisting of the above with the polymer, and the concentrated platelet liquid was treated in the same blood circuit to determine the leukocyte removal rate and the platelet recovery rate. The results are shown in Table 1.

[0032]

Comparative Example 1 As a coating polymer, a homopolymer containing only HEMA was synthesized by the same operation as in Example 1, and the same non-woven fabric filter material as in Example 1 was coated with the polymer to obtain a leukocyte selective trapping filter.
The concentrated platelet liquid was processed in the same blood circuit to obtain the leukocyte removal rate and the platelet recovery rate. The results are shown in Table 1.

[0033]

[Comparative Example 2] HEMA and DMM without MTGMA
A copolymer having a mole fraction of A of 0.97 or 0.03 was synthesized, and a filter material made of the same non-woven fabric as in Example 1 was coated with the polymer to obtain a leukocyte trapping filter. The concentrated platelet liquid was processed in the blood circuit, and the leukocyte removal rate and the platelet recovery rate were calculated. The results are shown in Table 1.

[0034]

[Comparative Example 3] HEMA and DMAM without MTGMA
A copolymer having a mole fraction of A of 0.90 or 0.10 was synthesized, and a filter material made of the same non-woven fabric as in Example 1 was coated with the polymer to obtain a leukocyte trapping filter. The concentrated platelet liquid was processed in the blood circuit, and the leukocyte removal rate and the platelet recovery rate were calculated. The results are shown in Table 1.

[0035]

[Comparative Example 4] Using a non-woven fabric having no coating on the filter medium, the concentrated platelet liquid was treated in the same blood circuit as in Example 1 to determine the leukocyte removal rate and the platelet recovery rate. The results are shown in Table 1.

[0036]

Example 3 MEMA and DMAMA and methoxypolyethylene glycol methacrylate having different number of repeating units of polyethylene oxide chain (hereinafter abbreviated as MPGMA)
Non-woven fabric was coated with the terpolymer of and the concentrated platelet liquid was treated to obtain leukocyte removal rate and platelet recovery rate.
A copolymer (hereinafter abbreviated as HDM-3) in which the number of repeating units of polyethylene oxide chains is 3 is used as the MPGMA and the molar content% of DMAMA is 10% by mole and the molar content% of MPGMA is 5% by mole. The polymerization was carried out under the same conditions as in Examples 1 and 2 and Comparative Examples 1 to 4 above. Non-woven fabric with an average fiber diameter of 1.2 μm is used as the filter material, and the effective filtration area is 30 × 30 mm.
In a container having an inlet and an outlet for blood, 10 non-woven fabrics (about 0.6 g) were filled so that the packing density was 0.15 g / cm ³ , to obtain a leukocyte selective capture filter. HDM-
The non-woven fabric was coated with the 3 copolymer to obtain a leukocyte selective capture filter. When a blood circuit incorporating the filter was used to process 230 g of concentrated platelet liquid at a flow rate of 1.2 g and a flow rate of 5 g / min, the leukocyte removal rate was 9%.
It was 9.8% and the platelet recovery rate was 90.5%. The results are shown in Table 1.

[0037]

Example 4 A polymer (hereinafter referred to as HDM-) was prepared in the same manner as in Example 3 except that the number of repeating units of MTGMA was 9.
(Abbreviated as 9) was coated and coated with the same non-woven filter material as in Example 3, and the concentrated platelet liquid was treated using the same blood circuit as in Example 3 to obtain leukocyte removal rate and platelet recovery rate. However, the leukocyte removal rate is 98.0%,
The platelet recovery rate was 92.7%. The results are shown in Table 1.

[0038]

Example 5 MPGMA and DMA having 9 repeating units
A nonwoven fabric having an average fiber diameter of 1.2 μm was immersed in an aqueous solution (1000 ml) containing MA in a molar content of 33% and 67% and a polymerizable monomer weight% of 2.0% by weight, and nitrogen was ventilated. Degassed. Γ-rays of 3.6 kGy (1.2
(kGy / hour) for irradiation for graft polymerization. The non-woven fabric was taken out, thoroughly washed with water, dried with hot air at 40 ° C. for 15 hours, and further vacuum dried for 2 hours. The non-woven fabric was dried. The graft ratio was 12.8%. The thus obtained non-woven fabric after grafting was treated with a concentrated platelet liquid using the same blood circuit as in Example 3, and the leukocyte removal rate and the platelet recovery rate were determined. As a result, the leukocyte removal rate was 98.4.
%, And the platelet recovery rate was 91.3%. The graft ratio is a value calculated according to the following formula (3). The results are shown in Table 1.
Shown in.

[0039]

Comparative Example 5 A polymer similar to that of Example 3 except that the number of repeating units of MPGMA was 18 (hereinafter referred to as HDM-18
Abbreviated), and the platelet concentrate was processed using the same blood circuit as in Example 3, and the leukocyte removal rate and the platelet recovery rate were determined. The leukocyte removal rate was 87.2% and the platelet recovery rate was 94. It was 0.0%. The results are shown in Table 1.

[0040]

Comparative Example 6 A polymer similar to that of Example 3 except that the number of repeating units of MPGMA was 30 (hereinafter, HDM-30
Abbreviated), and the platelet concentrate was processed using the same blood circuit as in Example 3, and the leukocyte removal rate and the platelet recovery rate were determined. The leukocyte removal rate was 80.3% and the platelet recovery rate was 96. It was 0.4%. The results are shown in Table 1.

[0041]

Comparative Example 7 An aqueous solution containing only 2.0% by weight of a macromer having 30 repeating units of MPGMA (1000 m
A non-woven fabric having an average fiber diameter of 1.2 μm was dipped in 1), and nitrogen was ventilated to remove the air. Γ-rays of 3.6 kG were added to this aqueous solution.
Graft polymerization was carried out by irradiation with y (1.2 kGy / hour). Take out the non-woven fabric, wash it thoroughly with water, and at 40 ° C for 1
After drying with a hot air for 5 hours and further vacuum drying for 2 hours to dry the nonwoven fabric, the graft ratio was 18%.
The thus obtained non-woven fabric after grafting was treated with a concentrated platelet liquid using the same blood circuit as in Example 3, and the leukocyte removal rate and the platelet recovery rate were determined. As a result, the leukocyte removal rate was 64.6%. The platelet recovery rate was 98.8%. The results are shown in Table 1.

[0042]

[Table 1]

[0043]

EFFECTS OF THE INVENTION By using the filter material of the present invention for a leukocyte removal filter, leukocytes can be efficiently removed while suppressing the loss of platelets, which is effective in the field of leukocyte ablation therapy for platelet transfusion and immune disorder. It provides a means.

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Claims (1)

[Claims] 1. A filter material is a polymer porous body having fibers or continuous pores composed of a body portion and a surface portion, and at least the surface portion of the filter material has a basic nitrogen-containing functional group and a repeating unit of 2 to 2. A leukocyte selective trapping filter material comprising 15 polyethylene oxide chains.