JPH1112183A - Filter medium for removing leukocyte and removal of leukocyte - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leukocyte-removing filter medium high in leukocyte removability per unit volume and good in the flowability of a leukocyte- containing fluid, and to provide a method for using the same. SOLUTION: This leukocyte-removing filter medium comprises ultrafine fibers and short fibers having a specific average fiber diameter and an average fiber length. Therein, the ultrafine fibers are carried on the short fibers, and a network structure is formed with the ultrafine fibers. The short fibers have an average fiber diameter of 1.5-30 μm and an average fiber length of 0.5-10 mm, and the ultrafine fibers have an average fiber diameter of 0.01-1.0 μm. The porosity of the fiber medium is 50-95%, and the ultrafine fiber-holding degree of the filter medium is 0.1-30 wt.%. The ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 2-500. The method for removing leukocyte comprises filtering a leukocyte- containing fluid with the filter medium. The leukocyte-containing fluid includes whole blood preparations, erythrocyte preparations and thrombocyte preparations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leukocyte removal filter material for removing leukocytes from a leukocyte-containing liquid, and a method for removing leukocytes using the filter material.

[0002]

2. Description of the Related Art Conventionally, in the field of blood transfusion, in addition to so-called whole blood transfusion in which a blood collected from a blood donor is added with an anticoagulant, a recipient of a whole blood product is required. What is called component blood transfusion is generally performed in which a blood component is separated and the blood component is transfused. Component transfusions include red blood cell transfusion, platelet transfusion, plasma transfusion, etc., depending on the type of blood component required by the recipient, and blood component products used for these transfusions include red blood cell products,
Platelet preparations, plasma preparations, etc. In recent years, so-called leukocyte-removal transfusion, in which a blood product is transfused after removing leukocytes mixed in the blood product, has become widespread. This includes relatively minor side effects such as headache, nausea, chills, and non-hemolytic fever associated with blood transfusion, alloantigen sensitization that has a serious effect on the recipient, viral infection, and GV after blood transfusion.
This is because it has been revealed that serious side effects such as HD are mainly caused by leukocytes mixed in blood products used for blood transfusion.

[0003] Methods for removing leukocytes from blood products include:
It is roughly divided into a centrifugal separation method that separates and removes white blood cells using the difference in specific gravity of blood components using a centrifugal separator, and a filter material made of a porous material such as a fiber material or a porous material having continuous pores. There are two types of filter methods for removing leukocytes. The filter method is currently most popular because it has advantages such as excellent leukocyte removal ability, simple operation, and low cost.

[0004] The mechanism of the leukocyte removal by a filter using a fiber material or a porous material is mainly based on the adsorption of leukocytes to the surface of the filter material. Therefore, as a technique for improving the leukocyte removing ability of the filter material, for example, Japanese Patent Publication No. 2-13587 discloses a technique using a nonwoven fabric having a small fiber diameter as the filter material. In addition, a lump of fibrous particles (small fiber pieces) having a total length of about 1 mm and a width of about 1 μm to 50 μm and a short fiber that can be woven is dispersed in a dispersion medium. ,
The leukocyte removal filter material produced by removing the dispersion medium from the obtained dispersion is Japanese Patent Publication No. 7-500090,
It is disclosed in JP-A-7-31677 and WO95 / 17236. Further, Japanese Patent Application Laid-Open No. 2-46857 discloses a filter material in which a fibrous material having a diameter of 1 μm or more and a length of 1 μm or more is formed on the surface of a material fiber which is not harmful to blood. The above technique aims at increasing the surface area of the filter material by using a nonwoven fabric or a small fiber piece having a small fiber diameter, and improving the leukocyte removal ability. However, with the filter material of the prior art, the blood filtration time is extended and the pressure loss is increased with the improvement of the leukocyte removal ability, and it is difficult to simultaneously achieve high leukocyte removal ability and good blood filtration characteristics. Met.

[0005]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a leukocyte-removing filter material which has an extremely high leukocyte-removing capacity per unit volume as compared with a conventional filter material and has a good flow of a leukocyte-containing liquid. To provide. A second object of the present invention is to provide a method for removing leukocytes having a good blood flow while efficiently removing leukocytes from leukocyte-containing liquids such as whole blood products, red blood cell products, and platelet products. is there.

[0006]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors, short fibers having an average fiber diameter of 1.5 μm or more and less than 30 μm, an average fiber length of 0.5 mm or more and less than 10 mm, and holding the short fibers A filter material made of ultrafine fibers having an average fiber diameter of 0.01 μm or more and less than 1.0 μm, wherein the porosity of the filter material is 50% or more and less than 95%, and the retention amount of the ultrafine fibers to the filter material is 0.1% by weight or more. Weight percent, the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 2 or more and less than 500, and the first object can be achieved by the leukocyte removal filter material in which the ultrafine fibers form a network structure. Was found.

That is, according to the present invention, the average fiber diameter is 1.5 μm.
m or more and less than 30 μm, short fibers having an average fiber diameter of 0.5 mm or more and less than 10 mm, and the average fiber diameter held by the short fibers is 0.01 μm
A filter material comprising ultrafine fibers having a size of not less than 1.0 μm and less than 1.0 μm, wherein the porosity of the filter material is 50% or more and less than 95%, and the retention amount of the ultrafine fibers with respect to the filter material is 0.1% by weight.
The present invention relates to a leukocyte removal filter material wherein the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 2 or more and less than 500, and the ultrafine fibers form a network structure.

[0008] The leukocyte-removing filter material of the present invention comprises a short fiber having an average fiber diameter and an average fiber length of a specific length,
An appropriate amount of ultrafine fibers having an extremely small fiber diameter was introduced, and the ultrafine fibers formed a network-like structure capable of efficiently capturing leukocytes, so that the ability to remove leukocytes could be significantly improved. In addition, because of the high porosity, it was possible to simultaneously maintain good blood flowability.

Hereinafter, the leukocyte removal filter material of the present invention will be described in more detail. The average fiber diameter of the short fibers and the ultrafine fibers referred to in the present invention is measured by the following procedure. From the leukocyte removal filter material, a portion recognized as substantially uniform is sampled and photographed using a scanning electron microscope or the like. At the time of sampling, the effective filtration cross-sectional area of the filter material is divided by a square having a side of about 0.5 cm, and six places are randomly sampled. In order to perform random sampling, for example, after designating an address to each of the above sections, a section of a necessary portion may be selected by a method such as using a random number table. In addition, for each sampled section, at least 3 places, preferably at least 5 places
Take a photo at 1000x or more. 0.1mm to 10 on this photo
Place a transparent sheet on which grid lines are drawn vertically and horizontally at equal intervals of about mm and measure the width of the fiber at the intersection of the vertical and horizontal lines, that is, the fiber at the grid point, in the direction perpendicular to the fiber axis. This is defined as the fiber diameter. By such a random selection, the width of each of the 100 or more fibers is measured for each of the short fibers and the ultrafine fibers, and the value obtained by number-averaging them is calculated as the average fiber diameter of each of the short fibers and the ultrafine fibers. I do. 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 or become thicker, etc., these data are used. Is deleted.

The short fiber of the present invention has an average fiber diameter of 1.5 μm or more and less than 30 μm. If the average fiber diameter of the short fibers is less than 1.5 μm, the strength of the filter material is reduced, which is not suitable. When the average fiber diameter of the short fibers is 30 μm or more,
When a base material made of short fibers is produced, the inter-fiber distance between short fibers becomes large, making it difficult to form a network structure of ultrafine fibers, which is not suitable. The average fiber diameter of the more preferable short fiber is 2.0 μm or more and less than 20 μm, more preferably
3.0 μm or more and less than 12 μm.

The average fiber diameter of the ultrafine fibers of the present invention is 0.01 μm
It is less than 1.0 μm. Average fiber diameter of ultrafine fiber is 0.01
If it is less than μm, the strength is weak, and fibers are easily cut by white blood cells and other blood cell components that collide when processing a liquid containing white blood cells, which is not suitable. Further, if the average fiber diameter of the ultrafine fibers is 1.0 μm or more, the porosity of the filter material becomes small, the flow of the leukocyte-containing liquid becomes poor, and the surface area of the filter material that adheres to leukocytes becomes small. Not suitable. In order to efficiently contact and capture leukocytes at multiple points, the average fiber diameter of the ultrafine fibers is 0.02
μm or more and less than 0.8 μm, more preferably 0.1 μm or more
More preferably, it is less than 0.6 μm.

In order to maintain a good flow of the leukocyte-containing liquid,
The ratio between the average fiber diameter of the short fibers and the average fiber diameter of the ultrafine fibers is particularly preferably 2 or more and less than 500. If the ratio between the average fiber diameter of the short fibers and the average fiber diameter of the ultrafine fibers is less than 2, the voids of the short fiber base material are closed off by the ultrafine fibers, and the flow of the leukocyte-containing liquid becomes extremely poor. . When the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 500 or more, it is difficult to hold the ultrafine fibers so as to cover the voids of the short fiber base material, and the leukocyte removal ability is extremely reduced. In addition, the entanglement between the ultrafine fibers and the short fibers becomes insufficient, and the ultrafine fibers may fall off the filter material, which is not suitable. More preferably, the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 4 or more and less than 200, more preferably 5
Not less than 100.

The short fiber of the present invention has an average fiber length of 0.5 mm or more.
It is less than 10 mm. The average fiber length of the short fibers is a value obtained by measuring the fiber lengths of 50 or more short fibers and performing a number average.
If the average fiber length of the short fibers is less than 0.5 mm, the strength of the leukocyte removal filter material is insufficient, which is not suitable. When the average fiber length of the short fibers is 10 mm or more, the short fibers are not suitable for producing the filter material because it becomes difficult to uniformly disperse the short fibers throughout the filter material. The average fiber length of the preferred short fiber is 1
mm or more and less than 7 mm, more preferably 2 mm or more and less than 6 mm.

The leukocyte-removing filter material of the present invention may be composed of a branched fiber in which short fibers and ultrafine fibers are integrated, that is, branch-like ultrafine fibers are branched from short fibers serving as a trunk. Such a branched fiber and a monofilament short fiber and / or an ultrafine fiber may be mixed. The term “branched fiber” as used herein refers to a fiber having both a trunk-like short fiber having a large fiber diameter and a branch-like ultrafine fiber having a small fiber diameter. In other words, the main component is a branched fiber having an average fiber diameter of 1.5 μm or more and less than 30 μm and an average fiber length of 0.5 mm or more and less than 10 mm and a branch-like fiber having an average fiber diameter of 0.01 μm or more and less than 1.0 μm. It is a leukocyte removal filter material.

The material of the single fiber-like short fiber of the present invention or the branched fiber having both the trunk-like short fiber and the branch-like ultrafine fiber is:
Any of polyurethanes, polyesters, polyolefins, polyamides, polystyrenes, polyacrylonitriles, celluloses, cellulose acetates, and the like can be used as long as they can form short fibers and branched fibers in a desired form. The monofilament short fibers of the present invention and the trunk-like short fibers in the branched fibers are more preferably in a non-linear form such as a curved or meandering form. If the short fibers are in a linear form, the short fibers are in contact with each other along the fiber axis, and it is not preferable because blood is difficult to flow in the contacted portion and the filtration time is prolonged. Non-linear short fibers are preferable because good blood flowability can be ensured, and a network structure of ultra-fine fibers can be formed and held in the space of the short fiber base material.

Further, in the leukocyte-removing filter material of the present invention, the retention amount of the ultrafine fibers with respect to the filter material is small.
It is preferable that the content be 0.1% by weight or more and less than 30% by weight. If the retained amount is less than 0.1% by weight, it is not suitable because a sufficient amount of ultrafine fibers for capturing leukocytes in the leukocyte-containing liquid cannot be obtained. If the holding amount is 30% by weight or more, the amount of the ultrafine fibers introduced into the short fiber base material becomes too large, and the voids in the short fiber base material are closed, so that the leukocyte-containing liquid does not flow. The amount of microfiber retained in the filter material is 0.5% by weight or more and less than 25% by weight, and more than 2% by weight
More preferably, it is less than 20% by weight.

The measurement of the amount of retained ultrafine fibers can be measured by various methods. For example, it can be determined from the change in weight before and after holding the ultrafine fibers on the short fiber base material. In addition, only ultrafine fibers are dissolved and extracted from the filter material, and the extracted components are analyzed by differential scanning calorimetry, high performance liquid chromatography, nuclear magnetic resonance spectrum, elemental analysis,
The quantification may be performed by using an X-ray or infrared spectrum. When the ultrafine fibers are made of cellulose, the leukocyte-removing filter material of the present invention is immersed and shaken in a solution in which cellulase is dissolved, and the cellulose of the ultrafine fibers is decomposed into glucose. It may be obtained by quantifying the amount.

In the leukocyte removal filter material of the present invention, the porosity is preferably 50% or more and less than 95%.
If the porosity of the filter material is less than 50%, the flow of the leukocyte-containing liquid is poor and not suitable. If the porosity is 95% or more,
Since the mechanical strength of the filter material is weak, the filter material is crushed when the leukocyte-containing liquid is treated, and the filter material no longer functions as a filter material. A more preferable porosity is 70% or more and less than 90%.

The porosity is measured by measuring the dry weight (W ₁ ) of the filter material cut into a predetermined area, and measuring the thickness to calculate the volume (V). This filter material is immersed in pure water, degassed, and the weight (W ₂ ) of the hydrated filter material is measured. From these values, the porosity is determined by the following calculation formula. Note that ρ in the following calculation formula
Is the density of pure water. Porosity (%) = (W ₂ −W ₁ ) × ρ × 100 / V

In the leukocyte-removing filter material of the present invention, ultrafine fibers having an extremely small average fiber diameter form a network structure. Such a network structure is held on a base material made of short fibers. In the present invention, the network structure composed of ultrafine fibers is held by the short fiber base, and the network structure exists so as to cover the space between the short fibers as the base and is fixed to the short fiber base. Means that it is being done.

The physical structure of the leukocyte removal filter material of the present invention will be described below. In the leukocyte removal filter material of the present invention, the average fiber diameter is 0.01μm or more 1.0μm
A plurality of microfibers having a mean fiber diameter of 1.5 μm or more and less than 30 μm and an average fiber length of 0.5 mm or more and less than 10 mm are held by a short fiber base material. However, the ultrafine fibers forming the network structure are not bundled, and a plurality of ultrafine fibers are physically entangled to form a network structure. As the mesh structure referred to in the present invention,
When the ultrafine fibers have a curved structure, a structure in which curved meshes are connected may be mentioned.

If the network structure formed by the ultrafine fibers is uniformly held by the short fiber base material in a cross section perpendicular to the flow of the leukocyte-containing liquid, leukocytes can be efficiently captured. It is preferred. The fact that the network structure is uniformly held on the short fiber base in the cross section perpendicular to the flow of the leukocyte-containing liquid means that the filter material is randomly sampled in the cross section perpendicular to the flow of the leukocyte-containing liquid. Introduced amount (density) of microfiber in each part of
Is substantially equal, and the amount of introduction can be actually determined by measuring the variation in the amount of microfibers present in a fixed amount of filter material in each portion of the sampled leukocyte removal filter material.

In the leukocyte-removing filter material of the present invention, it is particularly preferable that the ultrafine fibers are substantially uniformly introduced into the entire filter material and are held by the short fiber base material to form a substantially uniform network structure. That is, in the leukocyte-removing filter material of the present invention, the amount of microfibers introduced in each part of the filter material randomly sampled in a cross section perpendicular to the flow of the leukocyte-containing liquid is substantially equal, and in each part, It is particularly preferable that the distributions of the sizes of the meshes are substantially equal and almost the same mesh-like structure is formed. More specifically, a uniform network structure is formed when the network structure at each part of the filter material sampled at random is a network having a size similar to that observed by an electron microscope. , And a state that is recognized to be almost the same. When a uniform network structure is not formed, the distribution of the mesh size in each part differs greatly when the network structure in each part of the filter material sampled at random is observed. Is also a state that can be clearly determined to be different.

In order for the ultrafine fibers to form a network structure in the filter material of the present invention, the average fiber diameter must be 0.01 μm or more.
It is necessary that ultrafine fibers having a size of less than 1.0 μm have properties such as a curved shape. Further, even an ultrafine fiber which does not originally have a curved shape can be processed by heat treatment, mechanical treatment or various chemical treatments so as to be suitable for the present invention.

The following is an example of a method for producing ultrafine fibers that can be used in the present invention. Average fiber diameter is 0.01μm or more
The ultrafine fibers of less than 1.0 μm include regenerated cellulose, purified cellulose, splittable fibers represented by microporous splittable acrylic fibers, etc., as well as JP-B-47-37648 and JP-A-50-56.
No. 50, the splittable conjugate fiber obtained by a known method described in JP-A-53-38709, etc., or physically stirred using a mixer or the like, or jet a high-pressure liquid flow,
It can be produced by, for example, treating with a high-pressure homogenizer.

Also, as a fiber material that is easily curved,
Cellulose, polyacrylonitrile, polyester, polyolefin, polyamide, etc. are suitable, but when processed into ultrafine fibers with an average fiber diameter of 0.01 μm or more and less than 1.0 μm, the ultrafine fibers may be bent by heat treatment or mechanical treatment. Any material that can be used can be used.

After the regenerated cellulose fiber or the purified cellulose fiber among the above-mentioned splittable fibers is subjected to an acid treatment or an alkali treatment as required, the mixture is physically treated with a mixer or the like in a liquid for 30 to 90 minutes. The fibril fiber obtained by stirring and fibrillating is particularly preferable because it becomes an ultrafine fiber having an average fiber diameter of 0.01 μm or more and less than 1.0 μm, and has a curved shape so that a network structure is easily formed. However, the above-mentioned fibril fibers may include thick fibril fibers having a fiber diameter of 1.0 μm or more, and such fibril fibers do not contribute to significantly increasing the leukocyte removal ability. For this reason, it is preferred that the suspension of fibril fibers obtained by physically stirring with a mixer or the like be filtered through a suitable filter medium such as a mesh to remove the fibril fibers having a large fiber diameter.

Further, a known sea-island type fiber is used as a raw material, which is subjected to a heat treatment or a mechanical treatment in advance as required, and the raw material fiber is processed into a curved shape.
Since the average fiber diameter obtained by dissolving and removing the sea component using various solvents and having a mean fiber diameter of 0.01 μm or more and less than 1.0 μm also has a curved shape, it constitutes the leukocyte removal filter material of the present invention. It can be used as an ultrafine fiber.

In the case of producing a branched fiber in which short fibers and ultrafine fibers are integrated, the above-mentioned splittable fiber or splittable composite fiber is physically stirred using a mixer or the like, or a high-pressure liquid stream is injected. Alternatively, when it is treated with a high-pressure homogenizer, it can be obtained by treating under relatively weak conditions such that the split, branch-like ultrafine fibers do not separate from the short fibers as the trunk. Among them, a method of obtaining a branched fiber using a regenerated cellulose fiber or a purified cellulose fiber is particularly preferable because the operation is easy and the network structure is easily formed because the branch-like fibril fiber has a curved shape. As a method for producing a branched fiber from a cellulose fiber such as a regenerated cellulose fiber or a purified cellulose fiber, a cellulose fiber cut to an appropriate fiber length is subjected to an acid treatment or an alkali treatment as necessary, and then a mixer, etc. By physically stirring in a liquid for several minutes in a liquid to produce ultrafine fibril fibers from the cellulose fibers as the trunk. Further, the cellulose fiber can be sand-washed with a paper file, or can be manufactured using a beater such as a beater or a refiner.

Next, an example of a method for producing the leukocyte removal filter material of the present invention will be described below. Filter material consisting of ultrafine fibers and short fibers, filter material consisting only of branched fibers,
As a method for producing the filter material of the present invention, such as a filter material comprising a branched fiber and a monofilament short fiber and / or ultrafine fiber, there is a papermaking method using a fiber dispersion. As a papermaking method, a dispersion is prepared by dispersing fibers in an appropriate dispersion medium containing water, a surfactant, a thickener, and the like, and the dispersion is poured into an appropriate container, and once collected, drained. And a method of drying the obtained filter material. In such a papermaking method, the concentration of the fiber in the dispersion medium is preferably from about 0.01 g / L to about 3 g / L, and when a surfactant or a thickener is added, the concentration is about 0.03 g / L.
Preferably it is from 01% to about 5%. Further, in the production of the dispersion of the fiber, for the purpose of improving the handleability in the production process, for example, the paper may be formed on a suitable base fabric such as a nonwoven fabric or a mesh, or the filter material may be formed on the base fabric after the formation. You may sandwich it.

Further, as post-processing, about 3 kg / cm ² or more and about 2
It can also be processed with a high pressure liquid stream of less than 00 kg / cm ² . Such post-processing is preferable because it can increase the entanglement between the fibers and increase the mechanical strength. A second object of the present invention is to provide a method for removing leukocytes having a good blood flow while efficiently removing leukocytes from leukocyte-containing liquids such as whole blood products, red blood cell products, and platelet products. is there. The present inventors have found that the above-mentioned second object is achieved by filtering a leukocyte-containing liquid using a filter device appropriately filled with the leukocyte-removing filter material of the present invention.

That is, the leukocyte removal method of the present invention comprises treating a leukocyte-containing liquid with a leukocyte removal filter device filled with the leukocyte removal filter material of the present invention, and collecting the filtered liquid. More specifically, 1) an inlet, 2) a filter including the leukocyte removal filter material of the present invention, and
3) A method for removing leukocytes from a leukocyte-containing liquid, which comprises injecting a leukocyte-containing liquid from an inlet using a device including an outlet, and collecting the liquid filtered by a filter from the outlet.

The filter device filled with the leukocyte-removing filter material referred to here is a filter device appropriately filled with the filter material of the present invention, and another filter is provided upstream and / or downstream of the filter material of the present invention. It may contain materials. In particular, it is preferable to arrange a pre-filter for removing microaggregates contained in the leukocyte-containing liquid on the upstream side of the filter material of the present invention, and a non-woven fabric having an average fiber diameter of about 10 μm to 50 μm is preferable as the pre-filter. Used.

The leukocyte-containing liquid to be filtered by the leukocyte-removing filter device of the present invention includes a whole blood preparation, a concentrated erythrocyte preparation, a concentrated platelet preparation, and a body fluid. When the leukocyte-containing liquid is a whole blood product or a concentrated erythrocyte product, the filter device capacity per unit is 3 mL or more and 20 mL.
It is preferable to treat the leukocyte-containing liquid with a leukocyte-removing filter device of less than. Here, one unit is about 300
Refers to whole blood products or concentrated red blood cell products in volumes of mL to 550 mL. If the capacity of the filter device per unit is less than 3 mL, it is not preferable because a high leukocyte removal rate cannot be achieved. Filter device capacity per unit
If the volume is 20 mL or more, the loss of useful components in the unrecoverable leukocyte-containing liquid remaining in the filter device, in other words, the amount of useful components, is not preferable.

When the leukocyte-containing liquid is a concentrated platelet preparation, the volume of the filter device per 5 units is 1 mL or more and 10 mL.
It is preferable to treat the leukocyte-containing liquid with a leukocyte-removing filter device of less than. Here, 5 units means about 170
Refers to a concentrated platelet product in the volume of mL to 200 mL. If the volume of the filter device per 5 units is less than 1 mL, there is a high possibility that a high leukocyte removal rate cannot be achieved, which is not preferable. If the capacity of the filter device per 5 units is 10 mL or more, unrecoverable useful components remaining in the filter device increase, which is not preferable.

When blood transfusion is performed simultaneously with blood transfusion at the hospital bedside using the filter device filled with the leukocyte removal filter material of the present invention, leukocytes should be at least 1 g / min.
Preferably, the leukocyte-containing liquid is filtered at a rate of less than g / min. On the other hand, when using a filter device filled with the leukocyte removal filter material of the present invention to remove leukocytes from a blood product for transfusion at a blood center, the leukocyte-containing liquid is filtered at a speed of 15 g / min or more and less than 100 g / min. Is preferred.

Further, by using the filter device filled with the leukocyte-removing filter material of the present invention, in addition to removing leukocytes which cause various side effects after blood transfusion from the blood product for transfusion, it is also useful for extracorporeal circulation of autoimmune diseases. It can be used in therapy to remove leukocytes. The extracorporeal circulation therapy for an autoimmune disease is a method of removing leukocytes from a body fluid by continuously filtering the body fluid of the patient, which is a leukocyte-containing fluid, and returning the collected fluid to the body. As described above, the leukocyte-removing filter material of the present invention has an extremely high affinity for leukocytes, and thus can efficiently process a leukocyte-containing liquid without lowering the processing speed.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail based on examples, but the scope of the present invention is not limited only to these examples.

[0039]

EXAMPLE 1 fiber diameter of about 12μm commercial flocculent refined cellulose fibers (Tencel ^R, manufactured by Kotoruzu Corporation) of cut so that the fiber length of about 5mm to. This cut fiber is immersed in an aqueous solution of sodium hydroxide (1% by weight) at about 5 ° C.
Stir gently for 60 minutes. After washing with water, it was immersed in an aqueous solution of sulfuric acid (3% by weight) and treated at 70 ° C. for 30 minutes with gentle stirring at 60 rpm. After washing with water again, the purified cellulose fiber was dispersed in water to a concentration of 2.0 g / L, and the mixture was vigorously stirred at 10,000 rpm for 30 minutes using a mixer. Further, the obtained dispersion is meshed with polypropylene mesh (#
50). By performing such a treatment, a suspension of fibril fibers in which purified cellulose fibers were fibrillated was prepared. When the obtained fibril fiber was photographed and observed with a scanning electron microscope, the average fiber diameter was 0.4
μm.

Next, a polyethylene terephthalate fiber having an average fiber diameter of about 3 μm was cut into a fiber length of about 3 mm and dispersed in water. When dispersing, use a commercially available surfactant (Tween
^R20 ) was added to a concentration of 0.1% by weight. By adding fibril fibers to this dispersion, a dispersion in which both polyethylene terephthalate fibers and fibril fibers were dispersed was obtained. The total fiber concentration was 0.25 g / L, and the content of fibril fibers in the total fiber weight was 7% by weight.

A polypropylene mesh (# 200)
It was cut into a square of 30 cm × 30 cm, placed on the bottom of a funnel-like papermaking apparatus, and further stored pure water to a height of about 1 cm from the mesh surface. The above-mentioned dispersion liquid (3.6 L) was gently poured into the mixture, stirred gently, and then drained from the bottom of the papermaking apparatus. The filter material formed on the mesh was vacuum dried at 40 ° C. for 16 hours. The filter material thus produced had a basis weight of about 40 g / m ² . The obtained filter material formed a network structure, the porosity was 86%, and the ratio of the average fiber diameter between the short fibers and the ultrafine fibers was 7.5.

Platelet-rich plasma was removed from whole blood prepared by adding 56 mL of CPD to 400 mL of blood by centrifugation within 8 hours after blood collection, and a concentrated erythrocyte preparation (hematocrit 60%) containing MAP as a erythrocyte preservation solution was added. ) Is prepared and 4
Stored at ５5 ° C. for 5 days. Produced by the spunbond method, the average fiber diameter was filtered above concentrated erythrocyte preparation in the filter which is filled with a filling density of 0.26 g / cm ³ is effective filtration sectional area of 33μm and 12μm of nonwoven fabric container 45cm ^2, Microaggregates in blood were removed.

Five sheets of the filter material obtained by the papermaking are stacked, and filled into a container having an effective filtration area of 36.0 cm ² (6.0 cm × 6.0 cm) so that the packing density becomes 0.22 g / cm ^3. A filter device having a device capacity of 5 mL was prepared. Using a circuit having an inlet and an outlet, incorporating this filter device, a concentrated erythrocyte preparation (100 mL) that had been left at room temperature of 22 to 25 ° C after removing microaggregates was injected through the inlet, and the filter device was used. The solution was discharged from the outlet through port and collected by filtration. Filtration was performed with a head of 1.0 m. The time required for filtration (filtration time) and the number of leukocytes before and after filtration were measured to determine the ability to remove leukocytes. The white blood cell count before filtration was determined by injecting a 10-fold dilution with a Turk's solution into a Barker-Turk type hemocytometer and counting the white blood cells using an optical microscope. The number of leukocytes after filtration was measured as follows. After thoroughly mixing the diluted solution diluted 5-fold with the leuco plate solution, the mixture was allowed to stand at room temperature for 6 to 10 minutes, centrifuged at 2750 × g for 6 minutes, and the supernatant was removed to adjust the amount to 1.02 g. This solution was injected into a nadget-type hemocytometer, and the number of white blood cells was counted using an optical microscope. The leukocyte removal ability was determined from the leukocyte counts before and after filtration, which were measured as described above. Leukocyte removal ability = -Log (white blood cell count after filtration / white blood cell count before filtration) As a result, the white blood cell removal ability was 4.7 and the filtration time was 5.1 minutes.

[0044]

Comparative Example 1 The same fibril fiber and polyethylene terephthalate short fiber as in Example 1 were used.
A dispersion to which 0.25 g / L of a surfactant was added was prepared. However, the content of fibril fibers in the total fiber weight is 0.
05% by weight. This dispersion is paper-made and the basis weight is about 40 g / m ²
Was prepared. The obtained filter material hardly formed a network structure, the porosity was 88%, and the ratio of the average fiber diameter of the short fibers to the ultrafine fibers was 7.5. When the concentrated red blood cell preparation was filtered using the same filter device and method as in Example 1, the leukocyte removal ability was 1.8 and the filtration time was
It was 3.6 minutes.

[0045]

Comparative Example 2 The same fibril fiber and polyethylene terephthalate short fiber as in Example 1 were used.
A dispersion to which 0.25 g / L of a surfactant was added was prepared. However, the fibril fiber content in the total fiber weight is 55
% By weight. This dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . The obtained filter material has a network structure with very small pores in which the voids of the short fibers are covered with fibril fibers, the porosity is 79%, and the ratio of the average fiber diameter of the short fibers to the ultrafine fibers is 7.5. there were. When the concentrated erythrocyte preparation was filtered using the same filter device and method as in Example 1, the blood flow stopped when about 20 g of blood was treated.

[0046]

Comparative Example 3 The same fibril fiber and polyethylene terephthalate short fiber as in Example 1 were used.
A dispersion to which 0.25 g / L of a surfactant was added was prepared. The content of fibril fibers in the total fiber weight was 7% by weight. This dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . 150 ° C while compressing this filter material
For 30 minutes. The obtained filter material formed a network structure, the porosity was 42%, and the ratio of the average fiber diameter between the short fibers and the ultrafine fibers was 7.5. When the concentrated red blood cell preparation was filtered using the same filter device and method as in Example 1, the leukocyte removal ability was 4.3 and the filtration time was 75 minutes.

[0047]

Comparative Example 4 A nonwoven fabric of polyethylene having an average fiber diameter of 0.6 μm manufactured by flash spinning was freeze-pulverized with liquid nitrogen to obtain a fine fiber mass. This fine fiber mass was added to a dispersion in which polyethylene terephthalate short fibers containing the same surfactant as in Example 1 were dispersed. The total fiber concentration was 0.25 g / L, and the content of polyethylene microfiber lump was 10% by weight. This dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . The obtained filter material did not form a network structure, the porosity was 81%, and the ratio of the average fiber diameter of the ultrafine fibers consisting of short fibers and polyethylene fibers was 5. When the concentrated red blood cell preparation was filtered using the same filter device and method as in Example 1, the leukocyte removal ability was 2.8 and the filtration time was 8.3 minutes.

[0048]

[Comparative Example 5] An average fiber diameter of about 34 μm and an average fiber length of about 3
Short fibers made of polyethylene terephthalate having a thickness of mm were dispersed in water containing a surfactant, and the same fibril fibers as in Example 1 were added to the dispersion. Total fiber concentration is 0.25g / L
And the content of fibril fibers was 10% by weight. This dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . The obtained filter material hardly formed a network structure, the porosity was 84%, and the ratio of the average fiber diameter of the ultrafine fibers consisting of short fibers and polyethylene fibers was 85.
When the concentrated erythrocyte preparation was filtered in the same manner as in Example 1, the leukocyte removal ability was 1.6 and the filtration time was 3.3 minutes.

[0049]

EXAMPLE 2 Short fibers made of polyethylene terephthalate having an average fiber diameter of about 6.4 μm and an average fiber length of about 3 mm were dispersed in water containing a surfactant, and the same fibril fibers as in Example 1 were dispersed in the dispersion. Was added. Total fiber concentration is 0.25g
/ L, and the fibril fiber content was 10% by weight.
This dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . The obtained filter material had a network structure, the porosity was 82%, and the ratio of the average fiber diameter of the short fibers to the fibril fibers was 16. When the concentrated red blood cell preparation was filtered using the same filter device and method as in Example 1, the leukocyte removal ability was 4.5 and the filtration time was 4.7 minutes.

Table 1 shows the results of Examples 1 and 2 and Comparative Examples 1 to 5.
Summarized in

[Table 1]

[0051]

EXAMPLE 3 regenerated cellulose fiber having a fiber diameter of about 15 [mu] m (Bemberg ^R NP spinning fiber, manufactured by Asahi Kasei Corporation) was cut to have a fiber length of about 5mm to. This cut fiber is immersed in an aqueous solution of sodium hydroxide (1% by weight) at about 5 ° C.
The mixture was gently mixed at 60 rpm for 60 minutes. After washing with water, it was immersed in an aqueous solution of sulfuric acid (3% by weight) and treated at 70 ° C. for 30 minutes with gentle stirring at 60 rpm. After washing with water again, the regenerated cellulose fiber was dispersed in water so as to have a concentration of 2.0 g / L, and the mixture was vigorously stirred at 10,000 rpm for 5 minutes using a mixer. In this way, the regenerated cellulose fiber was used as a branched fiber composed of a trunk fiber and a branch-like fibril fiber branched from the trunk fiber, and a dispersion containing the branched fiber was prepared. The obtained fibril fiber of the branched fiber and the fibril fiber separated from the trunk fiber were photographed with a scanning electron microscope and observed. The average fiber diameter was 0.5 μm.

In the prepared fiber dispersion, the total fiber concentration was 0.5 g / L, and the content of the ultrafine fibers present in the dispersion including the branch-like fibril fibers was 13% by weight. This fiber dispersion was paper-made to prepare a filter material having a basis weight of about 40 g / m ² . The obtained filter material had a network structure, the porosity was 83%, and the ratio of the average fiber diameter between the trunk fiber and the ultrafine fiber was 30. When the concentrated red blood cell preparation was filtered using the same filter device and method as in Example 1, the leukocyte removal ability was 4.0 and the filtration time was 5.2 minutes.

[0053]

Example 4 Ten filter materials of the present invention produced in the same manner as in Example 1 were stacked, and the effective filtration area was 45 cm ² (6.7%).
cm × 6.7 cm). The average fiber diameter of polyethylene terephthalate is about 33 on this filter material.
4 nonwoven fabrics having a basis weight of 50 g / m ² and a mean fiber diameter of polyethylene terephthalate of about 12 μm and a basis weight of 30 g / m ²
It was piled six non-woven fabric of m ^2. From the upstream side of the blood, a nonwoven fabric with an average fiber diameter of about 33 μm, a nonwoven fabric with an average fiber diameter of about 12 μm,
A filter device was prepared by stacking the filter materials of the present invention in this order. The packing density of the filter material of the present invention is 0.22 g / c
m ³ and the volume of the filter device was 25 mL.

Two units (600% of hematocrit) of the concentrated erythrocyte preparation stored at 4 to 5 ° C. for 7 days were allowed to reach room temperature of 22 to 25 ° C., and filtered using a circuit incorporating the above filter device. . Filtration was performed while adjusting using a roller clamp so that the flow rate was about 8 g / min.

The white blood cell count before and after filtration was measured,
Leukocyte removal ability was determined. The measurement of the white blood cell count before filtration was performed in the same manner as in Example 1, but the measurement of the white blood cell count after filtration was performed by an extremely sensitive method described below.
5% Ficoll 400DL EBSS solution (hereinafter referred to as Ficoll solution) in a bag containing the filtered blood (recovery liquid)
Was added while shaking and mixing with the same volume as the recovery solution, and the recovery bag was fixed on a plasma separation stand and allowed to stand for 40 minutes. After standing, the supernatant was gently collected so as not to disturb the sedimented erythrocyte layer, and then Ficoll solution was added again, and the same operation was repeated. The supernatant collected by the two operations was dispensed into a Corning 25350 centrifuge tube, centrifuged at 840 × g for 15 minutes, and the supernatant was discarded with an aspirator, taking care not to suck up the sediment. 200 mL of hemolyzed blood (1.145% ammonium oxalate physiological saline) was added to each centrifuge tube, mixed by shaking, and the supernatant was discarded with an aspirator in the same manner as described above. Collect the sediment in a 15-mL centrifuge tube, add hemolysate to make the total volume 15 mL, leave it at room temperature for 10 minutes, centrifuge at 468 xg for 10 minutes, leave 0.5 mL containing the sediment, and supernatant. Was discarded. After the solution containing the precipitate was sufficiently stirred to form a single cell suspension, 50 μL of a fluorescent staining solution (69.9 mg / L acridine orange solution) was added, followed by further stirring. By setting the leukocyte recovery rate in the above series of operations to 55%, injecting a solution containing a fluorescent staining solution into a nadget type hemocytometer, and counting the number of leukocytes using an optical microscope,
The white blood cell count after filtration was determined. As a result, the leukocyte removal ability was 6.7, and the number of remaining leukocytes was 8.6 × 10 ² .

[0056]

The leukocyte-removing filter material of the present invention is a leukocyte-removing filter material having an extremely high leukocyte-removing ability per unit volume and a good flow of a leukocyte-containing liquid. Further, by using the leukocyte removal filter material of the present invention, it is possible to provide a leukocyte removal method that simultaneously achieves a high leukocyte removal rate and good blood flow.

Claims (2)

[Claims] (1) an average fiber diameter of 1.5 μm or more and less than 30 μm;
A filter material comprising short fibers having an average fiber length of 0.5 mm or more and less than 10 mm and ultrafine fibers having an average fiber diameter of 0.01 μm or more and less than 1.0 μm held by the short fibers, wherein the porosity of the filter material is 50% Not less than 95%, the retention amount of the ultrafine fibers to the filter material is 0.1% by weight or more and less than 30% by weight, and the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the ultrafine fibers is 2
The leukocyte-removing filter material, wherein the ultrafine fibers form a network structure. 2. 1) Inlet, 2) Average fiber diameter is 1.5μm or more
A filter material comprising a short fiber having a mean fiber length of less than 30 μm and an average fiber length of 0.5 mm or more and less than 10 mm, and an ultrafine fiber having an average fiber diameter of 0.01 μm or more and less than 1.0 μm held by the short fiber. Ratio of the fine fibers to the filter material is 0.1% by weight to less than 30% by weight, and the ratio of the average fiber diameter of the short fibers to the average fiber diameter of the fine fibers is 2 to 500%. A filter containing the above-mentioned filter material, wherein the ultrafine fibers form a network structure, and 3) an outlet, and injecting a leukocyte-containing liquid from an inlet through the outlet. Recovering the liquid filtered by the method described in (1), the method comprising removing leukocytes from the leukocyte-containing liquid.