JPH05262656A - Filter for purifying platelet - Google Patents

Abstract

PURPOSE:To provide the filter having an excellent leukocyte-removing rate and a high platelet-recovering rate and used for purifying the platelet. CONSTITUTION:A filter capable of selectively removing leukocytes contained in blood components therefrom is characterized by holding a polymer comprising an alkoxyalkyl (meth)acrylate monomer of the formula (R<1> is H, methyl; R<2>, R<3> are 1-4C alkyl, the sum of the carbon atoms of R<2> and [R<3> being 2-5) as a main component. The method for holding the polymer on the filter includes a coating method, a graft polymerization method using radiations or UV light, and a plasma polymerization method. The filter for purifying the platelets is preferably nonwoven fabric, woven fabric or knit fabric comprising fibers each having a fiber diameter of 1-30mum, preferably 3-20mum, especially preferably a porous filter comprising a polyurethane resin and having a three-dimensional net structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a platelet purification filter for removing white blood cells from a liquid containing platelets.

[0002]

2. Description of the Related Art At present, the form of blood transfusion is shifting from whole blood transfusion to component transfusion in which only the components required by the patient are transfused, and the number and amount of platelet products used are increasing year by year. Also, with the recent increase in the number of patients with thrombocytopenia due to large-dose administration of chemotherapeutic agents to patients with malignant tumors, the importance of platelet transfusion has been increasing.

As a platelet preparation, a bag PC (concentrated platelet plasma Platel) which is currently prepared after collecting blood in a blood bag.
et Concentrate) and apheresis PC obtained by a component blood sampling device, both of which are platelet components separated by a centrifugation method.

However, in the current centrifugation method, P
Since white blood cells (mainly lymphocytes) are inevitable to be mixed in C, the white blood cells in the PC induce side effects such as fever after platelet transfusion, and many patients who have received frequent platelet transfusions are transfused. It is said to cause a refractory effect. As a cause of this,
Anti-HLA (Human lymphocyte antigen Human Leucocyte
Antigen) antibody, LCT (lymphopathic antigen Lympho
It is said that cytotoxic antigen) antibodies were generated.

[0005] Platelet transfusion requires frequent and large amounts of blood transfusion, which results in sensitization of patients to an unspecified large number of antigens. Particularly in patients transfused with 100 units or more of platelet preparation, It is said that LCT antibody is detected in 90% or more thereof. Even if blood platelets are transfused to a patient having these antibodies, the expected blood transfusion effect cannot be obtained because the platelets are destroyed in the body.

Various leukocyte-removing filters have been developed and are on the market until now. Most of them are natural fibers such as natural cellulose, polyester,
Synthetic fibers such as polyamide and polyacrylonitrile, or fibers such as glass fibers are packed in the column as they are, or have a filter part that is secondary processed into a non-woven fabric, etc., mainly in red blood cell preparations such as CRC The purpose was to remove leukocytes mixed in the. Although these leukocyte removal filters have a certain level of performance in removing leukocytes, they also remove platelets at the same time, and when used for removing leukocytes from platelet suspension or whole blood, their effect is not satisfactory. It was suitable.

As a method for solving these problems, a filter having a three-dimensional network continuous structure made of polyurethane resin is described in JP-A-3-173825. The filter for purifying platelets can selectively remove leukocytes mixed in the blood components from the blood components containing white blood cells and platelets such as platelet suspension, whole blood, etc. Although platelet adhesion is relatively low, it is still not sufficient,
Further improvements have been desired to improve the platelet recovery rate.

Similarly, as another method for solving the above-mentioned problems, a filter having a water-soluble, nonionic polymer bonded to the surface is described in JP-A-61-226056. The blood filter has a strongly hydrophilic surface having a water-soluble polymer bonded to the surface thereof, so that platelets do not adhere. However, there is a problem that the white blood cells to be removed are less likely to adhere. Further, a surface having a high water content or a surface having a strong hydrophilicity suppresses the adhesion of platelets, but activates the platelets to cause a change, which results in the formation of microaggregates and the in vivo (i) of the platelets.
It has also been reported to promote metabolism (consumption) in n vivo) (eg, Journalof Bio).
medical Materials Reserc
h, 25, 1991, 875-887 and Journal
of Lab. Clin. Med. , 95, 198
0,289-304, etc.).

Further, as another method for solving the above problems, a filter having a critical surface tension (hereinafter, also simply referred to as CWST) of at least 90 dyne / cm is described in Japanese Patent Laid-Open No. 1-249063. In the filter, a strong hydrophilic surface having a CWST of 90 dyne / cm or more is a surface produced by introducing a hydroxyl group or a carboxyl group, and like the blood filter, it has an advantage that platelets do not adhere, but leukocytes are also present. It had a problem that it became difficult to stick.

Further, in the blood filter having a strong hydrophilic surface as described in the above-mentioned JP-A-61-226056 and JP-A-1-249063, when it comes into contact with a blood cell component in a dry state, a liquid component May cause destruction of blood cell components (hemolysis),
Its use was limited.

Therefore, at present, there is no filter for purifying platelets (and excellent for removing leukocytes) which improves the recovery rate of platelets and suitably removes leukocytes. In order to keep platelet transfusion safer and to maintain a long transfusion effect, it is possible to remove leukocytes, particularly lymphocytes, from blood components containing leukocytes and platelets such as platelet suspension, whole blood, etc. to recover purer platelets. A filter for purifying platelets is required.

[0012]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a novel filter for purifying platelets.

The present invention also provides a filter for purifying platelets, which is capable of selectively removing leukocytes mixed in the blood components from blood components containing leukocytes and platelets such as platelet suspension and whole blood. The purpose is to provide.

A further object of the present invention is to provide a platelet purification filter having a high platelet recovery rate, which solves the above problems.

[0015]

Means for Solving the Problems As a result of intensive studies on various material surfaces in a filter for purifying platelets, the present inventors have found that adhesion of platelets to the surface of the filter is small and CWST is 90 dyne / cm. As a surface with relatively low hydrophilicity, the polymer containing alkoxyalkyl (meth) acrylate as a main component adheres to platelets, suppresses activation, suppresses activation of the complement system, and has an affinity with biological tissues. Focusing on the fact that it is one of the few synthetic polymers that simultaneously satisfy compatibility, it was found that the above objects can be achieved by forming a surface made of a polymer containing the alkoxyalkyl (meth) acrylate as a main component. Based on this, the present invention has been completed.

That is, the present invention relates to (1) a filter for selectively removing leukocytes mixed in blood components from blood components, the filter having the general formula (I)

[0017]

[Chemical 2]

(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are alkyl groups having 1 to 4 carbon atoms, and the total number of carbon atoms of R ² and R ³ is 2). It can be achieved by a filter for purifying platelets, characterized in that a polymer having an alkoxyalkyl (meth) acrylate monomer consisting of a natural number of ˜5) as a main component is retained on the filter surface.

The present invention can also be achieved by (2) a filter for purifying platelets, characterized in that the polymer is retained on the surface of the filter by a chemical bond.

Further, according to the present invention, (3) the filter is
It can also be achieved by the filter for purifying platelets according to the above (2), which is a porous filter made of a polyurethane resin and having a three-dimensional network structure.

Furthermore, the present invention provides the above (1) to (3), wherein the (4) alkoxyalkyl (meth) acrylate monomer is methoxyethyl (meth) acrylate.
It can also be achieved by the filter for purifying platelets described in any of 1.

The present invention can also be achieved by the filter for purifying platelets according to the above (1) or (2), wherein (5) the blood component is a platelet suspension.

The present invention further provides (6) a filter for reducing the number of white blood cells contained in a platelet concentrate, which is represented by the general formula (I):

[0024]

[Chemical 3]

(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are alkyl groups having 1 to 4 carbon atoms, and the total number of carbon atoms of R ² and R ³ is 2). A polymer having an alkoxyalkyl (meth) acrylate monomer composed of a natural number of 5 to 5) as a main component is held on the filter surface, and the critical surface tension of the filter surface is less than 90 dyne / cm. And a device for reducing the white blood cell count of the platelet concentrate.

[0026]

The alkoxyalkyl (meth) acrylate used in the present invention is represented by the above general formula (I), and R ² and R ³ are alkyl having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms. And R ² and R ³
Is a natural number of 2 to 5 in total. For example, methoxymethyl acrylate, methoxyethyl acrylate, methoxypropyl acrylate, methoxyisopropyl acrylate, methoxybutyl acrylate, ethoxymethyl acrylate, ethoxyethyl acrylate, ethoxypropyl acrylate, ethoxyisopropyl acrylate, isopropoxyethyl acrylate, butoxyethyl acrylate. , Methoxymethylmethacrylate, methoxyethylmethacrylate, methoxypropylmethacrylate, methoxybutylmethacrylate, ethoxymethylmethacrylate, ethoxyethylmethacrylate, isopropoxymethylmethacrylate, etc. are preferable, but methoxyethylacrylate is preferable from the viewpoint of economy and operability. is there.

The polymer retained on the surface of the filter of the present invention is not limited to the above-mentioned homopolymer of alkoxyalkyl (meth) acrylate, and the biocompatibility of the alkoxyalkyl (meth) acrylate is not impaired. Can be used by copolymerizing with other monomers. The amount of alkoxyalkyl (meth) acrylate in this case is usually 10 mol% or more, preferably 20 mol% or more in the copolymer. Examples of the monomer to be copolymerized include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, and other alkyl (meth) acrylates, and olefins such as propylene and ethylene. , Acrylonitrile, methacrylonitrile, styrene and the like. A monomer having no hydroxyl group or cationic group in the molecule is preferable because biocompatibility is not easily impaired.
The copolymer may be a random copolymer, a block copolymer, or a graft copolymer, and can be prepared by a known method such as radical polymerization, ionic polymerization, or polymerization using a macromer.

As a method for holding the polymer having an alkoxyalkyl (meth) acrylate as a main component on the surface of the filter, known methods such as a coating method, a graft polymerization method using radiation or ultraviolet rays, and a plasma polymerization method can be exemplified. The plasma polymerization method or the graft polymerization method is preferable because the polymer is bonded to the surface of the filter and elution into blood components does not occur. Here, the bond to the filter surface means that the polymer is bonded to the filter surface by a chemical bond such as a covalent bond,
It is characterized in that it is hardly eluted into a good solvent for the polymer.

Further, the filter for purifying platelets of the present invention includes, for example, porous filters, non-woven fabrics, woven fabrics, knitted fabrics, etc., but preferably has a fiber diameter of 1 to 30 μm.
m, preferably 3 to 20 μm, and a non-woven fabric, a woven fabric, a knitted fabric or the like, and the material thereof includes natural fibers such as cotton and hemp, and synthetic fibers such as nylon, polyester, polyacrylonitrile, and polyolefin. Alternatively, it is a porous filter having an average pore size of 1 to 10 μm, preferably 2 to 8 μm, or a combination of the porous filter and a fibrous filter. Further, the porous filter substrate constituting the filter for purifying platelets of the present invention is not particularly limited, for example, polyolefin,
Halogenated polyolefin, polyester, polyurethane, polysulfone, nylon, polyether sulfone,
Poly (meth) acrylate, butadiene-acrylonitrile copolymer, etheramide-polyamide block copolymer, ethylene-vinyl alcohol copolymer,
Alternatively, a mixture thereof or the like can be given. From the viewpoint of operation, it is preferably polyolefin, halogenated polyolefin, polyurethane, ethylene-vinyl alcohol copolymer, or a mixture thereof.
More preferably, it is a porous filter having a three-dimensional network structure made of a base material made of a polyurethane resin described later.

The blood component used in the present invention is not particularly limited, but is preferably a platelet concentrate or a platelet concentrate for which platelet components have been separated by a component blood sampling device or the like as a platelet preparation for platelet transfusion. A suspension or the like.

Further, the filter for purifying platelets of the present invention has a critical surface tension of 90 dy on the surface of the filter.
less than ne / cm, preferably 75-88 dyne / c
m, more preferably 80 to 85 dyne / cm.

[0032]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

For the filters described in these examples and comparative examples, the critical wet surface tension (hereinafter, CW
The numerical values measured by the following experimental methods are shown for the leukocyte removal rate and the platelet recovery rate by the measurement method of ST) and the hemofiltration experiment.

CWST Measurement Method First, in the CWST measurement, a series of standard liquids whose surface tension was sequentially changed by 2 to 4 dyne / cm were prepared. At least two of the continuous surface tension standard liquids were separately dropped onto a representative portion of the porous substrate and allowed to stand for 10 minutes, after which time observations were made. (Where "wet"
Was defined as having at least 9 out of 10 drops absorbed or apparently wet to the porous substrate within 10 minutes. Also, "non-wetting" was defined as at least 9 out of 10 drops not absorbed or wetted by the porous substrate in 10 minutes. 3.) Measurements were continued using successively higher or lower surface tension liquids until the closest pair of surface tensions, one wet and the other not wet, were identified. The CWST then fell into this range and, for convenience, the average of the two surface tensions was used as the single number representing the CWST.

Appropriate solutions having different surface tensions can be prepared by various methods, and those used in Examples and Comparative Examples of the present invention are as shown in Table 1 below.

[0036]

[Table 1]

Experimental method for leukocyte removal rate and platelet recovery rate
Law Each porous body thickness of 0.5 mm, was incorporated within the predetermined punching to the size of 25mm diameter module (effective area 1.
2 cm ² ). On the other hand, autologous lymphocytes separated by density gradient centrifugation were suspended in PRP collected from CPD-added fresh blood of a healthy person, and the lymphocyte-containing PRP (PLT:
3.5 × 10 ^{5 to} 5.5 × 10 ⁵ / μl, WBC: 3.
5 × 10 ^{3 to} 4.5 × 10 ³ / μl).

5 ml of the above-mentioned lymphocyte-containing PRP was allowed to flow with a drop of 10 cm, and WBC before and after passing through the porous body,
After the PLT was measured, it was calculated by the following formula 1 and formula 2.

[0039]

[Equation 1]

[0040]

[Equation 2]

Example 1 A polyurethane porous filter (manufactured by Toyo Polymer Co., Ltd .: Rubicell) was placed under argon gas (0.1 Tor).
r), 100 W, 20 seconds after low temperature plasma irradiation,
Supplying methoxyethyl acrylate in the gas phase, 0.9
Graft polymerization was performed at Torr for 5 minutes. The pore size after washing the filter with methanol was 5 μm.
Then, CWST and graft ratio (weight of grafted polymer / weight of substrate before grafting × 1) for the filter
00 [%]) was measured and subjected to filtration experiments to measure leukocyte removal rate and platelet recovery rate. The results obtained are shown in Table 2.

Example 2 A polyurethane porous filter (manufactured by Toyo Polymer Co., Ltd .: Rubicell) under argon gas (0.2 Torr) was used.
r), 100 W, 30 seconds after low temperature plasma irradiation,
By supplying methoxybutyl acrylate in the gas phase, 0.6
Graft polymerization was performed at Torr for 5 minutes. The pore size after washing the filter with methanol was 4 μm.
Then, CWST and graft ratio (weight of grafted polymer / weight of substrate before grafting × 1) for the filter
00 [%]) was measured and subjected to filtration experiments to measure leukocyte removal rate and platelet recovery rate. The results obtained are shown in Table 2.

Comparative Example 1 Polyurethane porous filter used as a substrate in Examples 1 and 2 (manufactured by Toyo Polymer Co., Ltd .: Rubycell)
After washing with methanol, CWST and graft ratio (weight of grafted polymer / weight of substrate before grafting × 1
00 [%]) was measured and subjected to filtration experiments to measure leukocyte removal rate and platelet recovery rate. The results obtained are shown in Table 2.

[0044]

[Table 2]

Reference Example To examine the adhesion of platelets to the material surface, the materials shown in Table 3 were subjected to a platelet adhesion test. That is, human fresh platelet-rich plasma anticoagulated with sodium citrate was brought into contact with the material surface for 30 minutes, rinsed with physiological saline and fixed with glutaraldehyde, and the number of adhered platelets was observed with an electron microscope.

The results obtained are shown in Table 3 below, but the adhesion of platelets to the alkoxyalkyl (meth) acrylate surface was small.

[0047]

[Table 3]

[0048]

The filter for purifying platelets of the present invention has a polymer containing an alkoxyalkyl (meth) acrylate as a main component on its surface. The alkoxyalkyl (meth) acrylate has only an ether bond and an ester bond as a polar group in the molecule, and these polar groups are different from nitrogen atom (amino group, imino group), carboxyl group and the like. Since it does not have strong electrostatic interaction with biological components, it is difficult for foreign matter to be recognized by tissues and body fluids. Moreover, since the alkoxyalkyl (meth) acrylate does not have a large hydrophobic group and has appropriate hydrophilicity, it does not have a strong hydrophobic interaction with biological components. Considering the contact between the material surface and blood components, a surface with less protein denaturation, multi-layer absorption, activation, etc. is preferable, and hydrophobic interactions and electrostatic interactions that are major interactions between substances are reduced. Are considered useful. The filter of the present invention has a polymer containing an alkoxyalkyl (meth) acrylate as a main component on the surface, and as a result, the adhesion of platelets is small and the recovery rate of platelets is improved.

According to the present invention, it is possible to provide a leukocyte-removing agent and a leukocyte-removing filter which have an excellent leukocyte removal rate and a high platelet recovery rate. Such leukocyte-removing agent and leukocyte-removing filter are useful as a platelet purification filter and a leukocyte-removing filter for preventing side effects in blood transfusion such as platelets and fresh blood.

Claims (1)

[Claims] 1. A filter that selectively removes leukocytes mixed in blood components from blood components,
General formula (I): (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are alkyl groups having 1 to 4 carbon atoms, and
A polymer containing an alkoxyalkyl (meth) acrylate monomer consisting of R ² and R ³ as a natural number of 2 to 5) is held on the filter surface. Platelet purification filter.