JP3250833B2 - Leukocyte selective capture filter material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter material for selectively capturing leukocytes, which selectively captures leukocytes and allows platelets to pass therethrough. Specifically, when performing transfusion or extracorporeal circulation, leukocyte selection to selectively capture and remove leukocytes in blood or to selectively capture and remove leukocytes mixed when preparing concentrated platelet plasma from blood For capture filter materials.

[0002]

2. Description of the Related Art In recent years, with the progress of immunology and blood transfusion, the concept of component transfusion for transfusing only blood components that a patient really needs from conventional whole blood transfusion has become widespread and implemented. Various blood products such as erythrocyte concentrate (CRC), platelet concentrate (PC), and platelet poor plasma (PPP) used for component transfusion are adjusted by separating and fractionating blood obtained by donating blood by centrifugation. You.

[0003] However, the blood product fractionated by the centrifugation operation contains many leukocytes, and this mixed leukocyte may cause relatively minor side effects such as headache, non-hemolytic fever reaction, chills, and nausea. , Alloantigen sensitization, G after blood transfusion
Inducing serious side effects such as VHD and viral infection has been regarded as a problem, and various measures have been taken to remove leukocytes from blood products.

[0004] 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 fine material such as a nonwoven fabric or a porous material having continuous pores as a filter material. However, the filter method is widely used because of its high leukocyte removal efficiency, simple operation, and low cost.

However, most of the above filter materials are made of a hydrophobic polymer material, so that not only leukocytes but also platelets generally having high adhesiveness are adsorbed and removed. For patients with diseases such as aplastic anemia, thrombocytopenic purpura, and leukemia, transfusing a blood product containing a large amount of platelets such as whole blood, concentrated platelets, and red blood cell concentrate to replenish platelets is not possible. Indispensable, if the above-mentioned filter is used as it is, leukocytes are captured, but platelets necessary for the patient are also adsorbed and removed, and if transfusion is performed without using a filter, there is a concern about post-transfusion side effects. Therefore, development of a filter that suppresses platelet loss and selectively captures white blood cells has been desired.

[0006] The attachment of platelets to the material surface depends on the nature of the material surface. Based on this idea, known techniques for suppressing platelet adhesion include methods of graft polymerizing a hydrophilic monomer on the surface of a filter material and coating a hydrophilic polymer on the surface of the filter material. Have been. However, the material obtained in this way suppresses the adhesion of platelets and makes it difficult for white blood cells to be easily removed, and thus cannot be used as a filter for the purpose of selectively capturing only white blood cells.

Japanese Patent Application Laid-Open No. 55-129755 discloses a method of collecting leukocytes and lymphocytes containing little red blood cells and platelets using a filter having a nonwoven fabric surface coated with an antithrombotic material. However, when this filter is used, although the loss of platelets is small, the capturing power of leukocytes is also small and not satisfactory.

[0008] WO 87/05812 discloses a leukocyte selection method that uses a filter material in which the surface portion of the fiber contains a nonionic hydrophilic group and a basic nitrogen-containing functional group to reduce platelet capture and efficiently capture leukocytes. A removal filter is disclosed. The use of this filter makes it possible to selectively capture and remove leukocytes and has the effect of suppressing the capture of platelets, but the development of a filter that can collect platelets with high adhesiveness in higher yield is desired. Have been.

In order to selectively capture and remove leukocytes and allow platelets to pass, it is necessary to consider the physical and chemical factors of the filter material. The physical factor refers to the physical structure of the filter material.For a fibrous medium such as a nonwoven fabric, the fiber diameter, density, thickness, etc. correspond to this.For a porous body having continuous pores, the pore diameter, porosity, density , Thickness and the like correspond to this. Generally, the physical factor of the filter material greatly contributes to the capture of leukocytes, and to enhance the capture ability, it is configured by using ultrafine fibers with a small fiber diameter, increasing the packing density, and reducing the pore size. It is known. However, when the leukocyte capturing ability is improved by this method, clogging of blood cells is liable to occur, which may cause a long filtration time, and also increases platelet loss due to adsorption and adhesion of platelets to the filter material. Met. Therefore, if an attempt is made to increase the fiber diameter or increase the pore diameter of the porous body in order to suppress the adsorption of platelets to the filter material, the platelet passage ability is improved, There is a problem that the capturing ability of the phenol decreases. For this reason, in order to develop a target leukocyte selective capture filter for this purpose, it was necessary to chemically modify the surface of the filter material so as to capture leukocytes but pass platelets. However, as described above, grafting or coating a hydrophilic monomer or polymer improves platelet passage ability, but may decrease leukocyte capture ability. Therefore, in the chemical treatment of the leukocyte selective capture filter of the present purpose, it is necessary to maintain the leukocyte capture ability, and to hydrophilize platelets,
It was necessary to search for a monomer or polymer having a special structure and composition.

When a basic nitrogen-containing functional group is present on at least a 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 such positively charged filter material, the white blood cells and platelets have a negative charge and thus adhere well to the filter material. However, the leukocyte selective capture filter material of the present invention must be capable of capturing leukocytes and allowing platelets to pass therethrough.
Therefore, the presence of a basic nitrogen-containing functional group that imparts a positive charge alone also captures platelets, and cannot be used as a target filter material.

On the other hand, when blood is brought into contact with various polymer materials, there is a difference between the presence or absence of thrombus and the presence or absence of cell disruption depending on the selection of the material surface. Although this has not been elucidated yet, it is thought 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 materials", "medical polymer materials"). Editorial Committee,
1981). When classifying the material surface from the viewpoint of hydrophilicity and hydrophobicity, polymer materials having a hydrophilic surface generally have low interfacial energy between the material surface and blood, and therefore have a small interaction with proteins and blood cells, It is said that the formation of blood clots and the metamorphosis of cells tend to be suppressed ("Biomaterials Science" Vol. 2, 135,
1982). Therefore, the filter material must be hydrophilic in order to impart platelet-passing properties to the filter material.If 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. A substance having a polyethylene oxide chain has a property of being highly soluble in water because the polyethylene oxide chain has high polarity. It is known that a substance having a polyethylene oxide chain is an excellent blood compatible material having antithrombotic properties. For example, it is known that even when blood is brought into contact with the surface of a polymer material on which polyethylene oxide chains are present, plasma proteins such as albumin and globumin do not adsorb to the material surface, platelet reactivity decreases, and no thrombus formation is observed. (Yoshihito Raft, Medical Polymer Materials, Kyoritsu Shuppan, 1989). In addition, when separating the plasma component from the blood, if a porous membrane made of a substance having a polyethylene oxide chain and acrylonitrile is used, leukocytes, erythrocytes, and platelets are not adsorbed to the surface of the porous membrane, so the plasma component can be separated at a high water permeation rate. It is disclosed that the protein can be separated and the protein contained in the plasma is not adsorbed on the surface of the porous membrane, so that it can be recovered in a high yield (Japanese Patent Application Laid-Open No. 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 the platelets are filtered. It passes without adhering to the material surface. However, the leukocytes also passed at the same time, and could not be used as a target filter material. As described above, when emphasis is placed on capturing leukocytes, platelets are also captured, and when focusing on platelet permeability, leukocytes are generally allowed to pass at the same time.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a leukocyte selective capture filter material which suppresses platelet adsorption as much as possible and selectively captures and removes leukocytes at a high yield. Another object of the present invention is to provide a filter material used in a leukocyte selective capture filter that can be effectively used for platelet transfusion or extracorporeal circulating leukocyte removal therapy for blood and that efficiently removes white blood cells with little platelet adsorption. .

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to include a basic nitrogen-containing functional group and a polyethylene oxide chain having 2 to 15 repeating units in at least the peripheral surface portion of a fiber or a porous polymer having continuous pores. Is 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 ability to capture leukocytes is maintained, and platelets hardly adhere. It was found that the material had the property of passing through, and the filter material of the present invention was developed.

That is, the filter material for selective capture of leukocytes of the present invention is a filter material containing a basic nitrogen-containing functional group and a polyethylene oxide chain at least in the peripheral surface of a polymer or a porous polymer having continuous pores. It is.

The content of the basic nitrogen atoms in the surface portion of the filter material of the present invention is desirably 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 preferably 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. When the content of the basic nitrogen-containing functional group is less than 0.2% by weight, the positive charge on the surface of the filter material becomes insufficient, and the ability to capture leukocytes may be reduced. This is because sticking to the surface of the filter material may occur and platelet permeability may decrease. Further, the repeating unit of the polyethylene oxide chain exceeds 15, or 2
If the content is more than 2.0% by weight, the capturing ability of leukocytes may be reduced. If the content is less than 2.0% by weight, platelets tend 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, for example, by elemental analysis, infrared absorption spectrum, and nuclear magnetic resonance spectrum.

Examples of the material having a basic nitrogen-containing functional group which 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 include dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate from the viewpoint of easy availability and handleability. Further, as the material having a polyethylene oxide chain of the present invention, methoxytriethylene glycol,
Methacrylate (polyethylene oxide chain repeating unit = 3), methoxytetraethylene glycol, methacrylate (polyethylene oxide chain repeating unit = 4), methoxypentaethylene glycol methacrylate (polyethylene oxide chain repeating unit =
5) and the like.

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

Generally, a fibrous medium such as a non-woven fabric or a porous body having continuous pores has a hydrophobic surface, and the above-mentioned basic functional group or polyethylene is added to a filter material having such a hydrophobic surface. The introduction of an oxide chain is performed by coating a 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; It is achieved by graft polymerization to the filter material.

When a polymer containing a basic nitrogen-containing functional group and a polyethylene oxide chain is introduced onto the surface of the material by coating, other blood-compatible polymerizable polymers that do not have a basic nitrogen-containing functional group and a polyethylene oxide chain. It is also preferable to use a copolymer with a monomer. The polymerizable monomer that can be used is not particularly limited, for example,
Acrylic acid derivatives, methacrylic acid derivatives, allyl alcohol, styrene derivatives, acrylonitrile and the like can be mentioned. Among them, acrylic acid or methacrylic acid ester is preferable from the viewpoint of availability and handleability, and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and the like are particularly effective in stably holding the coating material on the material surface. There is also excellent.

As the filter material for capturing leukocytes of the present invention, a fibrous medium such as a nonwoven fabric or a porous body having continuous pores is preferable. 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 leukocyte capture ability. That is, when a fibrous medium such as a nonwoven 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,
Desirably less than 2.0 μm. Further, the filling density when the fibrous medium is filled in a container is 0.1 g / cm ³ or more,
Less than 0.3 g / cm ³ is preferred. Average fiber diameter is 0.3
μm, the packing density is 0.3 g / cm ³ or more,
Clogging of blood cells and an increase in pressure loss may be caused, 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 ability to capture leukocytes may be reduced. It is.

In the present invention, the average fiber diameter means a value determined according to the following procedure. That is, a part of the filter element, which is regarded as substantially uniform, constituting the filter is sampled and photographed using a scanning electron microscope or the like. At the time of sampling, the effective filtration sectional area of the filter element is divided by a square having a side of 0.5 to 1 cm, and three or more, preferably five or more are randomly sampled from among them. In order to perform random sampling, for example, after specifying an address in each of the above sections, a section at a necessary place or more may be selected by a method such as using a random number table. For each sampled section, three or more, preferably five or more locations are photographed. The diameter of all the fibers in the photograph thus obtained is measured. Here, the diameter refers to the width of the fiber in a direction perpendicular to the fiber axis. The value obtained by dividing the sum of the diameters of all the measured fibers by the number of fibers is defined as the average fiber diameter. However,
When multiple fibers are overlapped and their width cannot be measured due to the shadow of other fibers, or when multiple fibers are melted and become thicker, fibers with significantly different diameters are mixed. If so, these data are deleted. By the above method, the average fiber diameter is determined from data of 100 or more, preferably 1,000 or more.

When a porous body having continuous pores is used as a filter material, it is desirable that the porous body has an average pore diameter of 3 to 50 μm. If the average pore size is less than 3 μm, clogging of blood cells, an increase in pressure loss, and a longer filtration time are concerned.
If the average pore size exceeds 50 μm, there is a possibility that the ability to capture leukocytes may be reduced. Here, the average pore diameter in the present invention is an average pore size of one porous body before filling in a container, and is an MFP (Mean Flow Pore) measured by a Coulter Porometer 2 (Coulter Electronics and Limited, USA).
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 immersed in a solution obtained by dissolving the polymer in a suitable solvent, A simple operation such as squeezing the solution from the filter material and then drying with hot air can be performed. Further, in order to prevent the polymer from falling off from the filter material, heat can be applied to the coated filter material to further enhance the adhesion between the filter material and the polymer. Further, the graft polymerization of the polymerizable monomer having a polyethylene oxide chain having a basic nitrogen-containing functional group and a repeating unit of 2 to 15 to the filter material, after impregnating the filter material with a solution of the polymerizable monomer, Irradiation can be performed by a simple method of irradiating and washing with an appropriate washing liquid such as water.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to embodiments. The leukocyte removal rate and platelet recovery rate in the following examples are values obtained by the following equations (1) and (2), respectively. The leukocyte concentration before filtration was determined by counting the number of leukocytes of the blood diluted 10-fold with the Turk's solution using an optical microscope, and the leukocyte concentration after filtration was diluted 1.1-fold with acridine orange solution. The number of the leaked white blood cells was counted for the specimen thus obtained using a fluorescence microscope. The platelet concentration was determined 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; repeating unit of polyethylene oxide chain = 3), 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), and dimethylaminoethyl methacrylate (hereinafter abbreviated as DMAMA) Was synthesized by conventional solution radical polymerization. The polymerization conditions were such that the molar fractions of HEMA, DMAMA and MTGMA were 0.92, 0.03 and 0.05, and the total amount was 1
To an ethanol solution adjusted to mol / l, 2.2′-azobis (2.4-dimethylpareronitrile) (V-65) as an initiator was added at 1/200 mol / 1, and 5
The polymerization reaction was performed at 5 ° C. for 8 hours. The polymer was purified by adding the solution after the reaction to water and precipitating the polymer.

Ten nonwoven fabrics (about 0.1 g) having an average fiber diameter of 1.8 μm were obtained by measuring the effective filtration area to 21.5 × 21.5.
mm in a container having an inlet and an outlet for blood, so that the packing density of the nonwoven fabric is 0.2 g / cm ^3, and a 1% ethanol solution of the above polymer is charged into the container so that air does not enter. Was flowed at a flow rate of 2 l / min for 20 minutes to remove excess polymer solution. Furthermore, at 40 ° C., 1
The container after coating is vacuum dried for 5 hours, and then dried at 120 ° C. for 4 hours in order to improve the adhesion between the polymer and the nonwoven fabric.
Heat treated for hours. The content of basic nitrogen atoms contained in the filter material surface 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-mentioned leukocyte selective removal filter was incorporated in a blood circuit, and 0.79 g / mi using a syringe pump.
31.6 g of concentrated platelet solution was treated at a constant flow rate of n. The blood volume, leukocyte concentration, and platelet concentration before and after filtration were determined, and the leukocyte removal rate and platelet recovery rate were determined by 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 set to 0.85, 0.10, and 0.05, respectively. The filter material was coated with the polymer to obtain a leukocyte selective capture filter. The platelet concentrate was treated in the same blood circuit, and the leukocyte removal rate and platelet recovery rate were determined. Table 1 shows the results.

[0032]

Comparative Example 1 A homopolymer composed of only HEMA was synthesized as a coating polymer by the same operation as in Example 1, and the polymer was coated on a filter material made of a nonwoven fabric similar to that in Example 1 to obtain a leukocyte selective capture filter.
The concentrated platelet solution was processed in the same blood circuit, and the leukocyte removal rate and the platelet recovery rate were determined. Table 1 shows the results.

[0033]

[Comparative Example 2] HEMA and DMM containing no MTGMA
A copolymer having a molar fraction of A of 0.97 and 0.03 was synthesized, and the polymer was coated on a filter material made of the same nonwoven fabric as in Example 1 to obtain a filter for capturing leukocytes. The concentrated platelet solution was processed in the blood circuit, and the leukocyte removal rate and the platelet recovery rate were determined. Table 1 shows the results.

[0034]

[Comparative Example 3] HEMA and DDMA not containing MTGMA
A copolymer having a molar fraction of A of 0.90 and 0.10 was synthesized, and the polymer was coated on a filter material made of the same nonwoven fabric as in Example 1 to obtain a filter for capturing leukocytes. The concentrated platelet solution was processed in the blood circuit, and the leukocyte removal rate and the platelet recovery rate were determined. Table 1 shows the results.

[0035]

[Comparative Example 4] Using a non-woven fabric having no coating on the filter medium, the concentrated platelet solution was treated in the same blood circuit as in Example 1, and the leukocyte removal rate and the platelet recovery rate were determined. Table 1 shows the results.

[0036]

Example 3 HEMA, DMAMA and methoxypolyethylene glycol methacrylate having different numbers of repeating units of polyethylene oxide chain (hereinafter abbreviated as MPGMA)
Was coated on a nonwoven fabric, and the concentrated platelet solution was treated to determine the leukocyte removal rate and the platelet recovery rate.
As the MPGMA, a copolymer having a polyethylene oxide chain having three repeating units was used, and the molar content of DMAMA was 10 mol% and the molar content of MPGMA was 5 mol%. The polymerization was carried out under the same conditions as in Examples 1 and 2 and Comparative Examples 1 to 4 described above. A non-woven fabric having an average fiber diameter of 1.2 μm was used as a filter material, and the effective filtration cross-sectional area was 30 × 30 mm.
Then, 10 nonwoven fabrics (about 0.6 g) were packed in a container having an inlet and an outlet for blood so that the packing density became 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 230 g of the concentrated platelet solution was treated at a flow rate of 1.2 m and a flow rate of 5 g / min using a blood circuit incorporating the filter, the leukocyte removal rate was 9%.
9.8% and the platelet recovery was 90.5%. Table 1 shows the results.

[0037]

Example 4 Except that the number of repeating units of MTGMA was 9, a polymer (hereinafter referred to as HDM-
9), coated with the same nonwoven fabric filter material as in Example 3, processed the concentrated platelet liquid using the same blood circuit as in Example 3, and determined the leukocyte removal rate and platelet recovery rate. However, the leukocyte removal rate is 98.0%,
The platelet recovery was 92.7%. Table 1 shows the results.

[0038]

Embodiment 5 MPGMA and DMA Having 9 Repeating Units
A nonwoven fabric having an average fiber diameter of 1.2 μm is immersed in an aqueous solution (1000 ml) containing MA in a molar content of 33% or 67% and a polymerizable monomer in a weight% of 2.0% by weight. And degassed. 3.6 gGy (1.2 gamma) was applied to this aqueous solution.
(kGy / h) irradiation for graft polymerization. The nonwoven fabric was taken out, sufficiently washed with water, dried with hot air at 40 ° C. for 15 hours, and further vacuum-dried for 2 hours to dry the nonwoven fabric. As a result, the graft ratio was 12.8%. The nonwoven fabric after grafting thus obtained was treated with a concentrated platelet liquid using the same blood circuit as in Example 3, and the leukocyte removal rate and platelet recovery rate were determined. The leukocyte removal rate was 98.4.
%, And the platelet recovery was 91.3%. The graft ratio is a value determined according to the following equation (3). Table 1 shows the results
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).
The platelet 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. 0.0%. Table 1 shows the results.

[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).
The platelet 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. 0.4%. Table 1 shows the results.

[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 immersed in l), and deaerated by passing nitrogen through. 3.6 kG of γ-ray was added to this aqueous solution.
Irradiation of y (1.2 kGy / hour) was performed to perform graft polymerization. Take out the non-woven fabric and wash it thoroughly with water.
After drying with hot air for 5 hours, vacuum drying was further performed for 2 hours, and the nonwoven fabric was dried. As a result, the graft ratio was 18%.
The nonwoven fabric after grafting thus obtained was treated with a concentrated platelet liquid using the same blood circuit as in Example 3, and the leukocyte removal rate and platelet recovery rate were determined. The leukocyte removal rate was 64.6%. The platelet recovery was 98.8%. Table 1 shows the results.

[0042]

[Table 1]

[0043]

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 fields of platelet transfusion and leukocyte removal therapy for immunological disorders. It provides a means.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification symbol FI // B01D 39/00 A61M 5/16 334X (58) Investigated field (Int.Cl. ⁷ , DB name) A61K 35/14 A61M 1/02 A61M 1/34 A61M 5/165 B01D 15/00 B01D 39/00 BIOSIS (STN) CAPLUS (STN) MEDLINE (STN) EMBASE (STN)

Claims (1)

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