JP2002238996A - Leukocyte-removing filter device and leukocyte-removing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously realize high leukocyte removability and a high average processing speed, to obtain a high recovery rate of useful blood components, and to reduce the damage that the useful blood components suffers when removing the leukocytes which are the cause for the side effect of transfusion from a leukocyte containing liquid, in a leukocyte-removing filter device having a layer-like filter material including a porous element layer with a fiber structure to pour a leukocyte containing liquid from the upper side of the filter material and recover the filtered liquid down to the lower layer. SOLUTION: The layer of porous element having the fiber structure is provided a plurality of kinds of layers each having different weight in the fiber structure, and is laminated so that the higher the weight of the structure is, the lower is the layer where the structure is disposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a leukocyte removal filter device and a leukocyte removal method for removing leukocytes from a leukocyte-containing preparation.

[0002]

2. Description of the Related Art In recent years, in the field of blood transfusion, in addition to so-called whole blood transfusion, a recipient of a whole blood product is required in addition to so-called whole blood transfusion, in which an anticoagulant is added to blood collected from a donor. 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 erythrocyte transfusions, platelet transfusions, plasma transfusions, etc., depending on the type of blood component required by the recipient.The blood component preparations used for these transfusions include erythrocyte preparations, platelet preparations, and plasma preparations. and so on.

[0003] In recent years, so-called leukocyte-removed transfusion, in which a blood product is transfused after removing leukocytes mixed in the blood product, has become widespread. These include relatively minor side effects such as headache, nausea, chills, and non-hemolytic fever reactions associated with blood transfusions, as well as alloantigen sensitization that has a serious effect on the recipient, viral infection, and severe GVHD after blood transfusion. This is because it has been clarified that various side effects are mainly caused by leukocytes mixed in blood products used for blood transfusion.

In order to prevent relatively minor side effects such as headache, nausea, chills and fever, it is necessary to remove leukocytes from blood products until the residual ratio becomes 10 ^-1 to 10 ^-2 or less. It is said. It is also said that leukocytes should be removed until the residual ratio becomes 10 ^-4 to 10 ^-6 or less in order to prevent allergen sensitization and virus infection, which are serious side effects.

[0005] 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.

[0006] The filter method is now widely used because it has advantages such as excellent leukocyte removal ability, simple operation, and low cost. Furthermore,
Among the filter methods, the method of removing leukocytes by adhesion or adsorption using a nonwoven fabric as a filter material is currently most widely used because of its excellent leukocyte removal ability. The mechanism of the leukocyte removal by the filter device using the fiber material or the porous material is mainly based on the fact that the leukocytes in contact with the surface of the filter material adhere or adhere to the surface of the filter material.

[0007] Regarding the leukocyte removal ability of the filter device, the current leukocyte removal filter has a residual white blood cell count of 1 ×.
Although it has a leukocyte removal ability of 10 ⁵ or less, under these circumstances, the following three points can be cited as market requirements for a leukocyte removal filter.

The first point is that the recovery rate of useful components is improved, and the operation for recovering useful components remaining in the filter and the circuit due to the presence of physiological saline and air is not required, thereby improving the handling property. It is to make it. In particular, blood, which is a raw material of blood products, is often valuable blood provided by blood donation in good faith, and blood that remains in the leukocyte removal filter and cannot be collected is discarded as it is with the filter. Therefore, it is extremely significant to improve the useful component recovery rate over the current leukocyte removal filter. However, in the leukocyte removal filter using the conventional technology, the leukocyte removal ability of the residual leukocyte count of 1 × 10 ⁵ or less is required too much because the amount of the porous body is increased and the filter volume is increased. It was difficult to improve.

[0009] The second point is to achieve a higher leukocyte removal rate than current leukocyte removal filters and completely prevent serious side effects caused by leukocytes infused into patients. However, with the leukocyte removal filter using the conventional technique, it has been difficult to achieve a high leukocyte removal rate that can completely prevent such side effects by simply increasing the amount of the porous body. As a third point, a high average processing speed has been required in which the preparation processing time must not be longer than the current preparation processing time, while satisfying the first and second requirements.

As an attempt to solve such problems, PCT International Publication No. WO97 / 23266 discloses a porous element having an average pore size of 1 μm or more and less than 100 μm and an average fiber held by the porous element. 0.03μ in diameter
A filter material comprising a fiber structure having a length of not less than m and less than 1 μm, wherein the holding amount of the fiber structure with respect to the filter material is not less than 0.01 wt% and less than 30 wt%, and the ratio of the average pore diameter to the average fiber diameter of the porous element is 2 or more. A leukocyte-removing filter material having a molecular structure of less than 2,000 and a network structure is disclosed.

[0011]

According to the above prior art, the recovery of the useful component and the improvement of the leukocyte removal rate can be achieved by holding the fibers in the porous element and forming the fibrous structure. Because the fiber weight is constant, the filter material with a lower weight in order to increase the average processing speed has a lower leukocyte removal ability, while the filter material with a higher weight in order to increase the leukocyte removal ability has a higher density of red blood cells. The average processing speed at the time of filtration was low, and therefore it was difficult to simultaneously achieve high leukocyte removal ability and high average processing speed.

According to the present invention, a high recovery rate can be obtained without reducing the size and complicating operations so as to impair the leukocyte removing ability, and the leukocyte removing ability per unit volume is extremely higher than that of the conventional filter material. To provide a leukocyte-removing filter device which is high and has a good flow of a leukocyte-containing liquid, and further provides a leukocyte-removing filter material having good blood compatibility, which has little adverse effect on blood cells such as red blood cells and platelets. The purpose is to: It is another object of the present invention to provide a method for efficiently removing leukocytes from a leukocyte-containing liquid at a high average processing speed.

[0013]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that even a conventionally known layered filter material in which porous elements are laminated, a plurality of porous elements having different fiber structure weights. In addition, it has been found that a filter device having this as a main part can solve the above-described problem if the structure has a multilayer structure in which the basis weight gradually increases toward the lower layer side.

In addition, in the above-mentioned leukocyte removal filter device, the present inventors inject a leukocyte-containing liquid from the upper layer side of a layered filter material and collect a liquid filtered to a lower layer side, thereby obtaining a leukocyte-containing liquid. The inventors have found a method for efficiently removing the liquid, and have completed the present invention.

That is, the leukocyte removal filter device according to the present invention has a layered filter material including a plurality of layers of a porous element having a fibrous structure on at least the surface, and a leukocyte-containing liquid is injected from the upper layer side of the filter material. A leukocyte removal filter device from which the liquid filtered to the lower layer side is collected, there are a plurality of types of basis weight of the fiber structure, the more the porous element having a higher basis weight fiber structure, the lower the lower side Characterized in that they are layered so as to be arranged in the same manner.

By using the leukocyte-removing filter device of the present invention having the above-described structure, a high leukocyte-removing ability and a high average processing speed can be simultaneously achieved, and a high recovery rate of useful blood components can be obtained. Takes less damage.

Here, the porous element is a minimum structural unit constituting a filter material in a leukocyte removal filter device, and is a fiber aggregate, a porous membrane, or a sponge-like continuous porous body. For the purpose of the present invention, a fiber aggregate is preferable, and examples of the form include a nonwoven fabric, a woven fabric, and a knitted fabric. A nonwoven fabric that has been often used for a leukocyte removal filter is particularly preferable.

As the material of the porous element, any material can be used as long as it can form a nonwoven fabric, a woven fabric, a knitted fabric, a porous membrane, a sponge-like continuous porous body, and the like. , Polyolefin, polyamide, polyurethane, polystyrene, polyacrylonitrile, cellulose, cellulose acetate, and the like, but are not limited to the above examples.

The fibrous structure formed on the surface of the porous element is such that the fiber is present so as to cover the pores of the porous element, which is the base material, by being adhered or entangled, and does not easily fall off or elute. Say the part that is fixed. The fibrous structure only needs to be formed uniformly on at least the surface of the porous element, and even if the fibrous structure is distributed deep inside the porous element, it may be formed on one surface of the porous element or on both surfaces. It may be distributed.

As the material of the fiber forming the fibrous structure, any material can be used as long as it is fibrous and can be fibrillated by physical and chemical defibration. Examples thereof include polyester, polyolefin, polyamide, polyurethane, polystyrene, polyacrylonitrile, cellulose acetate, and aramid. It is not limited to the above examples.

The form of the fibrous structure is such that the fibers are retained without unevenness on the surface of the porous element base material, form network-like holes having a uniform average pore size, and are compressed in the thickness direction. It is desirable to maintain a certain level of bulkiness without having to do so.
In such a case, both high leukocyte removal performance and high filtration speed can be achieved.

Preferably, the average pore diameter of each of the porous elements contained in the filter material has a plurality of types.
The porous elements having smaller average pore diameters are layered so as to be arranged on the lower layer side. Thereby, higher leukocyte removal ability and average processing speed can be achieved.

Preferably, each of the porous elements contained in the filter material has an average pore diameter of 1 μm or more and 100 μm or more.
It is a porous element of less than μm. When the average pore size is less than 1 μm, the eyes are too clogged and the leukocyte-containing liquid does not easily flow. Conversely, when the average pore size is 100 μm or more, it is often difficult to form a uniform fibrous structure on the surface. Not suitable for the purpose of the invention.

Preferably, in the porous element having a fibrous structure on at least the surface, the average fiber diameter of the fibers forming the fibrous structure of each porous element is 0.02.
3 μm or more and less than 1 μm. Fibers having an average fiber diameter of less than 0.03 μm of the fibers forming the fibrous structure are brittle, and when processing the leukocyte-containing liquid at a high speed, the fibers are liable to be cut due to colliding leukocytes and other blood components. It is not preferred for the purpose of the invention. Further, fibers having an average fiber diameter of 1 μm or more are not preferable for the purpose of the present invention, because the opening ratio of the filter material becomes small and the flow of the leukocyte-containing liquid becomes poor.

Preferably, the filter material comprises a first porous element having at least a first fibrous structure having a basis weight of 0.1 g / m ² or more and less than 1.0 g / m ² , Is disposed on the upper layer of the porous element of
Lower than that of the fibrous structure of 0.01 g / m ² or more.
A second porous element having at least a surface of a second fiber structure of less than 3 g / m ² .

Here, the basis weight of the fibrous structure means the weight of the fibrous structure per unit area of one porous element.
It is a value measured by gravimetric method or extraction method.
The weight by the weight measurement method can be obtained from a change in weight before and after the formation of the fibrous structure on the porous element having a known area, and can be used when the weight is relatively large. On the other hand, the basis weight by the extraction method is used in order to obtain a higher accuracy than the gravimetric method when the basis weight is relatively small, and only the fibers of the fibrous structure are dissolved and decomposed and extracted, and the extracted components are quantified. Is the way. In this embodiment, this extraction method is adopted.

If a porous element having a fibrous structure for efficiently trapping lymphocytes and the like having a relatively small diameter and low adhesiveness is simply arranged directly below a porous element having no fibrous structure, The leukocyte fraction, which is relatively easy to remove, is too fine and undesirably only unnecessarily reduces the processing speed. Therefore, in the lower layer of the porous element having no fibrous structure, the lymphocytes are captured to some extent, and a relatively small-weight porous element that does not cause a large resistance to the leukocyte fraction that is easy to remove is arranged. When the porous element having a large basis weight is layered stepwise on the lower layer side, high removal performance can be obtained without lowering the processing speed.

Here, in order to achieve higher leukocyte removal than conventional filters, lymphocytes having a relatively small diameter and low adhesion among leukocytes are efficiently brought into contact with the filter material at multiple points and captured. For that purpose, it is preferable that the basis weight of the fiber structure is 0.1 g / m ² or more. However, if the basis weight is 1.0 g / m ² or more, the flow of the leukocyte-containing liquid becomes extremely poor, which is not suitable for the purpose of the present invention. Therefore, it is preferable that the basis weight of the fibrous structure of the porous element on the lower layer side necessary for achieving high leukocyte removal ability be 0.1 g / m ² or more and less than 1.0 g / m ² .

Further, a porous element having a basis weight of 0.3 g / m ² or more is layered on the lower layer side of the porous element having no fiber structure, and a lower layer side has a basis weight of 0.1 g.
/ M ² or more 1.0 g / m if a porous element having less than ² of the fiber structure was subjected to blood filtration test was carried out using a filter device comprising a filter material layer and layered, took too long to filtration . When disassembled after filtration, many clogging of the porous element was observed, which is considered to have caused a reduction in the processing speed. On the other hand, when the basis weight of the fiber structure was set to less than 0.01 g / m ² in the same filter device, the effect of increasing leukocyte removal by the fiber structure was not substantially exhibited. Therefore, the basis weight of the fiber structure on the surface of the porous element on the upper layer side is preferably 0.01 g / m ² or more and less than 0.3 g / m ² .

Preferably, the average pore size of the first fiber structure is 1 μm or more and less than 10 μm, the average pore size of the second fiber structure is 3 μm or more and less than 10 μm, and the average pore size of the first fiber structure is Larger than the pore diameter, and the upper layer of the second fiber structure does not hold the fiber structure,
And a third having an average pore diameter of 10 μm or more and less than 100 μm.
Are arranged.

That is, in order to achieve higher leukocyte removal than conventional filters, lymphocytes having a relatively small diameter and low adhesion among leukocytes are efficiently brought into contact with the filter material at multiple points and captured. It is necessary that the average pore diameter of the fiber structure be less than 10 μm. However, if the average pore diameter is less than 1 μm, the flow of the leukocyte-containing liquid becomes extremely poor, which is not suitable for the purpose of the present invention.
Therefore, it is preferable that the average pore diameter of the fibrous structure on the surface of the porous element necessary for achieving high leukocyte removal ability on the lower layer side be 1 μm or more and 10 μm.

However, if a porous element for efficiently trapping lymphocytes having a relatively small diameter and low adhesion is efficiently disposed just below the porous element having no fibrous structure, it is relatively difficult to collect. The leukocyte fraction which is easily removed is too fine and unnecessarily lowers the processing speed unnecessarily. Therefore, in the lower layer of the porous element having no fibrous structure, a certain amount of lymphocytes is captured, and, for the leukocyte fraction that is easy to remove, a relatively small average pore size that does not cause a large resistance is arranged. When a porous element having a smaller average pore diameter is further layered stepwise on the lower layer side,
As in the case of the basis weight of the fibrous structure, high removal performance can be obtained without lowering the processing speed.

With respect to this intermediate porous element, a porous element having an average pore diameter of less than 3 μm is overlaid on the lower layer side of the porous element having no fiber structure, and the lower layer is further provided with a fiber. When a blood filtration test is performed using a filter device including a layered filter material in which porous elements having an average pore diameter of 1 μm or more and less than 10 μm are laminated, the filtration takes a very long time. Since many clogging was observed in the porous element having an average pore diameter of less than 3 μm, it is considered that this caused a reduction in the processing speed. On the other hand, when the average pore diameter of the fiber structure of the intermediate porous element was 10 μm or more, the effect of increasing the leukocyte removal by the fiber structure was not substantially exhibited. Therefore, the average pore diameter of the fiber structure on the surface of the intermediate porous element is 3 μm.
It is preferable that it is not less than 10 μm.

Preferably, the surface of the filter material is coated with a graft polymer or a polymer material. As a result, the surface of the filter material is modified to a surface to which platelets or red blood cells are not easily adhered, the recovery rate of platelets and red blood cells is improved, and only white blood cells can be removed.

As the polymer material provided on the surface, a polymer material having a nonionic hydrophilic group is preferable. Examples of the nonionic hydrophilic group include a hydroxyl group, an amide group, and a polyether chain. Examples of a monomer that can be used for synthesizing a polymer material having a nonionic hydrophilic group include 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate.
-Hydroxyethyl acrylate, vinyl alcohol (prepared by hydrolyzing a polymer obtained by polymerizing vinyl acetate), methacrylamide, N-vinylpyrrolidone, and the like. Among the above monomers, 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate are preferred from the viewpoints of availability, ease of handling during polymerization, and processing performance of a leukocyte-containing liquid.

The polymer material used for the surface graft polymerization or the coating of the polymer material has a polymerizable monomer having a nonionic hydrophilic group and / or a basic nitrogen-containing functional group as a monomer unit of 0.1 to 40%. It is preferred that the copolymer contains less than mole%. As the basic nitrogen-containing functional group, a primary amino group, a secondary amino group,
Examples include a tertiary amino group, a quaternary ammonium group and the like, and a nitrogen-containing aromatic ring group such as a pyridyl group and an imidazole group.

Examples of the polymerizable monomer having a basic nitrogen-containing functional group include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, 3-dimethylamino-2-hydroxypropyl methacrylate, and bis (hydroxyethyl) amino-2. A derivative of methacrylic acid such as -hydroxypropyl methacrylate, a vinyl derivative of a nitrogen-containing aromatic compound such as allylamine, p-vinylpyridine, or 4-vinylimidazole, and a compound obtained by reacting the above vinyl compound with an alkyl halide or the like. A quaternary ammonium salt can be mentioned. Among the above polymerizable monomers, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and bis (hydroxyethyl) amino-2-hydroxypropyl methacrylate are preferred from the viewpoint of ease of handling at the time of polymerization and processing performance of a leukocyte-containing liquid.

When the monomer unit content of the polymerizable monomer having a basic nitrogen-containing functional group in the obtained copolymer is less than 0.1 mol%, the effect of suppressing platelet adhesion to the filter material surface is not so high. It is not preferable because it is not seen. Further, when the monomer unit content of the polymerizable monomer having a basic nitrogen-containing functional group in the copolymer is 40 mol% or more, useful components such as not only white blood cells but also platelets and red blood cells adhere to the filter material surface. It is not preferable because it becomes easy.

Next, a method for manufacturing the leukocyte removal filter device of the present invention will be described with reference to FIG. 1, but the present invention is not limited thereto. For example, single fineness 1.5
After cutting the dtex cellulose fiber to an appropriate length,
It is immersed in an aqueous sulfuric acid solution and subjected to an acid treatment while stirring gently. After the acid-treated cellulose fiber is washed with water and vigorously stirred in water for preferably 15 to 90 minutes using a mixer, the cellulose fiber fibrillates and becomes finer. 0
Fibers of 3 μm or more and less than 1 μm can be obtained. This treatment is particularly preferable because the fiber diameter is extremely small and a bent fiber can be easily obtained, so that the fiber structure is easily held by the porous element. For fibrillation, a high-pressure fluid stream may be sprayed instead of a mixer, or a high-pressure homogenizer, a disc refiner, or the like may be used.

Subsequently, the obtained fiber is preferably treated with 0.0
A fiber dispersion is obtained by dispersing in a dispersion medium to a concentration of from 01 g / L to 3 g / L. Water is preferred as the dispersion medium. Fig. 1 (a) of a fiber dispersion liquid such as a polyester nonwoven fabric
Is filtered through the porous element substrate 1 shown in FIG. Preferably, the average pore diameter of the porous element substrate 1 is 1 μm or more and less than 100 μm. As a result of this filtration, as shown in FIG. 1 (b), the remaining fibers are entangled with the pores in the upper part of the porous element substrate 1 to form the fiber structure 2, and the porous element 3 having the fiber structure 2 on the surface is formed. Is completed. Hereinafter, in the present specification, the above operation is referred to as papermaking. The basis weight of the fiber structure with respect to the porous element can be adjusted by changing the concentration of the fiber dispersion or the like. In addition, for the purpose of adjusting the adhesiveness of the blood component, surface modification with a polymer having a nonionic hydrophilic group may be performed, but is not particularly limited, and may be performed by a known method as necessary. Good.

The basis weight of the fibrous structure 2 with respect to the porous element substrate 1 can be adjusted by changing the concentration of the fiber dispersion or the like. Further, preferably, the porous element 3 holding the fiber structure 2 is dried and then coated with a polymer, so that the fiber is fixed so as not to be easily dropped or eluted in the preparation. Of course, the method of holding the fiber structure on the porous element substrate is such that the fibers are present so as to cover by bonding or entanglement to the pores of the porous element substrate, so that they do not easily fall off or elute by the preparation. The technical means is not limited to the above examples as long as the technical means is fixed.

Next, as shown in FIG.
The layers 3 are layered to form a layered filter material 4. Lamination
The order in which they are performed is, for example,
Porous with average pore size of 13μm without fiber structure on the surface
Element 1A (66 g / m weight) ^Two4), average also
Porous element 1B having a pore diameter of 10 μm (basis weight 40 g /
m^Two), And then a porous element substrate having an average pore diameter of 10 μm.
Material 1 (weight per fiber before holding 20 g / m^Two) On the surface, average
The basis weight formed by the fiber with a fiber diameter of 0.3 μm
0.1 g / m^TwoElement holding fiber structure 2
3, a porous element substrate 1 ′ having an average pore diameter of 10 μm
(20 g / m of basis weight before fiber holding)^Two) On the surface, average fiber
The basis weight formed by the fiber having a diameter of 0.3 μm is 0.
3g / m^TwoElement holding fiber structure 2 '
Let 3 'be 14 sheets. In the present invention, each porous element
The number of sheets and the like are not limited to the examples, and the size of the apparatus is not limited.
It may be adjusted appropriately according to the size and the like.

The above-mentioned layered filter material is used as a main part,
By properly filling a container having a blood inlet and a filtrate outlet according to a known method, the leukocyte removing apparatus of the present invention can be obtained. The present device may include another filter material on the upper layer side and / or the lower layer side of the layered filter material which is the main part. In general, leukocyte-containing liquids often contain microaggregates, and a prefilter can be used for the purpose of reducing clogging due to such microaggregates. Also, depending on the shape of the container, a post filter can be used to prevent uneven flow.
As the pre-filter and the post-filter, a fiber aggregate having an average fiber diameter of 8 μm to 50 μm or an average pore diameter of 20 μm is used.
A continuous porous body having pores of m to 200 μm is preferably used.

The cross-sectional area perpendicular to the flow direction of the leukocyte-containing liquid of the filter material of the leukocyte removal filter device is preferably 3 cm ² or more and less than 150 cm ² . Cross section is 3
If it is less than cm ² , the flow of the leukocyte-containing liquid becomes extremely poor, which is not preferable. If the cross-sectional area is 150 cm ² or more, the thickness of the filter must be reduced, and high leukocyte removal ability cannot be achieved, and the size of the filter device affects the recovery rate, which is not preferable.

The leukocyte-containing liquid to be filtered by the leukocyte-removing filter device of the present invention described above 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 device capacity per unit is 3 mL or more and 20 mL.
It is preferred to treat the leukocyte-containing liquid with a leukocyte removal filter device that is less than. Here, one unit is about 300
Refers to whole blood products or concentrated red blood cell products in the amount of mL to 500 mL. If the device volume per unit is less than 3 mL, a high leukocyte removal rate cannot be easily achieved, which is not preferable. If the unit capacity per unit is 20 mL or more, the loss of useful components in the unrecoverable leukocyte-containing liquid remaining inside the device, in other words, the amount of useful components, is not preferable.

When the leukocyte-containing liquid is a concentrated platelet preparation, it is preferable to treat the leukocyte-containing liquid with a leukocyte removal filter device having a device capacity per unit of 1 mL or more and less than 10 mL. Here, 5 units means about 170 mL
Refers to a concentrated platelet product in a volume of ２００200 mL. If the device capacity per 5 units is less than 1 mL, a high leukocyte removal rate cannot be easily achieved, which is not preferable. If the device capacity per 5 units is 10 mL or more, unrecoverable useful components remaining inside the device increase, which is not preferable.

When removing leukocytes from a blood product for transfusion at a blood center using the leukocyte removal filter device of the present invention, it is preferable to filter the leukocyte-containing liquid at a rate of 20 g / min to 100 g / min. .

The leukocyte removal filter device of the present invention is used not only for removing leukocytes which cause various side effects after blood transfusion from the preparation for transfusion but also for removing leukocytes in extracorporeal circulation therapy for autoimmune diseases. be able to. Extracorporeal circulation therapy for autoimmune diseases consists of removing leukocytes from body fluids by continuously filtering the patient's body fluid, which is a leukocyte-containing fluid, with a leukocyte removal filter device and returning the recovered fluid to the body. .

The present invention also provides a method for removing leukocytes, comprising injecting a leukocyte-containing liquid from the upper layer side of the filter material and collecting the liquid filtered to the lower layer side using the leukocyte-removing filter device. Disclose.

[0050]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited only to these Examples. Various numerical values used in the examples were measured by the following methods. (Measurement of average pore diameter of porous element)
When the mercury intrusion pressure is 6.898 kPa (1 psia), the mercury intrusion amount is 0%, and the mercury intrusion pressure is 18.27 MPa (26).
The pore diameter corresponding to the 50% mercury intrusion when the mercury intrusion at 50 psia) was taken as 100% was defined as the average pore diameter.

(Measurement of average pore diameter of fibrous structure formed on the surface of porous element) Since it cannot be determined by the above-mentioned mercury intrusion method, the surface of the porous element having the fibrous structure is scanned with a scanning electron microscope. A photograph was taken with a Hitachi S-2460N), the area of each binarized hole was determined by image processing, and the area was calculated as the number average of the diameter when converted to a circle.

(Measurement of Average Fiber Diameter) Using a scanning electron microscope (S-2460N manufactured by Hitachi, Ltd.), the sample surface was magnified by 5
Photographed at 00x. Using a polystyrene latex having a known diameter as a scale, the diameter was calculated by numerically averaging the diameters of 100 or more fibers randomly selected from photographs.
In addition, when the sample for measuring the average fiber diameter is a fibrous porous element, it means the average fiber diameter of the porous element, and in the case of a porous element holding a fiber structure, and the fiber structure In the case where the fibrils obtained by defibrating the fibers used for formation are fixed on an appropriate sample stage, the average fiber diameter of the fibrous structure is meant.

(Measurement of basis weight of fiber structure) Cellulase (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in acetic acid / sodium hydroxide buffer (pH = 4.8) to a concentration of 0.5 mg / mL. Then, several filter materials having a fiber structure having a known area were immersed in the solution and immersed at 50 ° C. for 24 hours.
After visually confirming that the cellulose fiber was completely dissolved, glucose in the decomposed liquid was quantified according to the operation procedure of a commercially available glucose determination reagent (glucose CII-Test Wako: manufactured by Wako Pure Chemical Industries, Ltd.). From the obtained amount of glucose, the weight of the fibrous structure per unit area of one porous element was calculated and used as the basis weight.

(Measurement of Leukocyte Residual Rate) The volume of the concentrated red blood cells before filtration (hereinafter, referred to as a pre-filtration liquid), the volume of the recovered liquid, and the number of leukocytes were measured, and the leukocyte residual rate was determined according to the following equation. Leukocyte residual ratio = (the number of leukocytes in the unit volume of the collected solution) / (the number of leukocytes in the unit volume of the filtered solution) Here, the volumes of the pre-filtered solution and the collected solution are each determined by the specific gravity of the blood product (1. 075). In addition, the leukocyte count of the pre-filtration solution was measured by injecting the pre-filtration solution diluted 10-fold with the Turk solution into a Bürker-Türk type hemocytometer and counting the leukocyte count using an optical microscope. .

(Measurement of the number of leukocytes in the recovered liquid) First, the recovered liquid was treated with a leuco plate solution (manufactured by SOBIODA) for 5 minutes.
Diluted 1-fold. After mixing the diluent well, 6 ~
Left for 10 minutes. This was centrifuged at 2750 × g for 6 minutes, and the supernatant was removed to adjust the liquid volume to 1.02 g. After thoroughly mixing the sample solution, the mixture was injected into a nadget type hemocytometer, and the number of white blood cells was counted using an optical microscope.

[Example 1] As a porous element as a substrate, a polyester nonwoven fabric ("Microweb" manufactured by Asahi Kasei Kogyo Co., Ltd.) having an average fiber diameter of 1 µm manufactured by a melt blow method was used. Average pore size of porous element substrate is 10μ
m, the thickness was 0.10 mm, the bulk density was 0.23 g / m ³ , and the basis weight was 20 g / m ² .

Next, a method for preparing fibers will be described. A Bemberg yarn (manufactured by Asahi Kasei Kogyo) having a single fineness of 1.5 dtex (average fiber diameter: 12 μm) was used as the cellulose fiber.
The fiber was cut to a fiber cut length of about 3 mm, immersed in a 5.5 wt% sulfuric acid aqueous solution, and subjected to an acid treatment at 70 ° C. for 60 minutes while gently stirring. After the treatment, the fibers are washed with water, and 1.5 g of the obtained fibers are dispersed in 1 L of water. When the mixture is vigorously stirred at 10,000 rpm for 15 to 90 minutes in water using a mixer, the fibers are fibrillated and finely divided, and the desired average fiber diameter becomes 0.0
Fibers of 3 μm or more and less than 1 μm can be obtained. In this example, stirring was performed for 15 minutes to obtain fibers having an average fiber diameter of 0.3 μm.

The fiber dispersion was coated with a Bemberg fiber having a basis weight of 0.2 g / m ^{2 on} one side of the polyester nonwoven fabric.
And 0.5 g / m ² . The basis weight of the fiber with respect to the porous element substrate was confirmed by an extraction method using cellulase, and it was confirmed that a predetermined amount was retained. As a result, the average pore diameter of the porous element having the fiber structure on the surface was 9 μm and 8 μm, respectively.

In preparing the filter material, six pre-filters having an average pore diameter of 130 μm and a nonwoven fabric having an average pore diameter of 13 μm (basis weight: 6
6 g / m ² ), two porous elements (average pore diameter 10 μm) having a basis weight of 40 g / m ² , and a basis weight of 0.2 g / m ^2.
Element having an average fiber diameter of 9μ
m), and a leukocyte removal filter including 14 porous elements (average pore diameter: 8 μm) each having a fibrous structure having a basis weight of 0.5 g / m ^{2 on} the surface was prepared (filter area: 45 cm ^2). ). Filter capacity is 18
mL.

The porous element of a nonwoven fabric having an average pore diameter of 13 μm, the porous element of a nonwoven fabric having an average pore diameter of 10 μm, and the porous element having a fibrous structure on its surface were prepared using hydroxyethyl methacrylate and bis (hydroxyethyl) amino-2-
Coating treatment was performed with an ethanol solution of a copolymer composed of hydroxypropyl methacrylate. As a result, the fibers are fixed so as not to be easily dropped or eluted in the preparation.

The concentrated erythrocytes (MAP) stored at 4 ° C. for 7 days
(CRC) 325 g was filtered with the above leukocyte removal filter device. The filtration of the concentrated red blood cells by the filter device was performed at a drop of 1 m, and the concentrated red blood cells were injected from the upper layer side of the filter material. Filtration was performed until the concentrated red blood cells disappeared from the blood bag, and the blood filtered from the lower layer side of the filter material was collected (hereinafter, the collected concentrated red blood cells are referred to as a collected liquid). The average processing rate when the concentrated red blood cells were filtered was 25 g / min.

As a result, the leukocyte residual rate was 10 ^−5.75 , and a high average processing speed and a high leukocyte removal rate were achieved. The free hemoglobin before and after the filtration was compared, but no difference was observed. It was found that the blood component was not damaged by the filter material.

Example 2 Fibers were prepared in the same manner as in Example 1, and the same porous element as the substrate as in Example 1 was used. The fiber dispersion was coated with a Bemberg fiber having a basis weight of 0.2 g / m ² , 0.7
g / m ² , the average pore diameter of the porous element having a fibrous structure on the surface was 9 μm and 6 μm, respectively.
μm.

In preparing the filter material, six pre-filters having an average pore diameter of 130 μm and two porous elements (having a basis weight of 66 g / m ² ) having an average pore diameter of 13 μm were arranged in order from the inlet port side to the outlet port side. ^Two porous elements having a pore size of 10 μm (basis weight 40 g / m ² ) and a basis weight of 0.2 g
/ 14 sheets porous element (average pore size 9 .mu.m) having fibrous structure m ² to the surface, the porous element basis weight has a surface fiber structure of 0.7 g / m ² (average pore size 6 [mu] m) 1
A leukocyte-removing filter containing four layers was prepared (filter area: 45 cm ² ). The filter capacity was set to 18 mL, and the coating treatment was performed in the same manner as in Example 1.

When a filtration test was conducted in the same manner as in Example 1, the average processing speed was 18 g / min. As a result, the leukocyte residual ratio was 10 ^−6.0 , and a high average processing speed and a high leukocyte removal ratio were achieved. The free hemoglobin before and after filtration was compared, but no difference was found.

Embodiment 3 Next, still another embodiment of the leukocyte removal filter device according to the present invention will be described. Preparation of the fiber was performed in the same manner as in Example 1, and the same porous element as the substrate as in Example 1 was used. When the fiber dispersion was paper-formed such that the basis weight of Bemberg fibers was 0.1 g / m ² and 0.3 g / m ² with respect to one surface of the polyester nonwoven fabric, the average pore diameter of the porous element having the fiber structure was 9% each. 0.5 μm and 8.5 μm.

In preparing the filter material, six pre-filters having an average pore diameter of 130 μm and two porous elements (having a basis weight of 66 g / m ² ) having an average pore diameter of 13 μm were arranged in order from the inlet port side to the outlet port side. ^Two porous elements having a pore size of 10 μm (basis weight 40 g / m ² ) and a basis weight of 0.1 g
/ M ² of fibrous structures (average pore size: 9.5 μm) on the surface, and a porous element having a fiber weight of 0.3 g / m ^{2 on} the surface (average pore size: 8.5 μm)
m) to prepare a leukocyte removal filter containing 14 layers (filter area: 45 cm ² ). The filter capacity was set to 18 mL, and the coating treatment was performed in the same manner as in Example 1.

When a filtration test was conducted in the same manner as in Example 1, the average processing speed was 30 g / min. As a result, the leukocyte residual rate was 10 ^−5.5 , and a high average processing speed and a high leukocyte removal rate were achieved. The free hemoglobin before and after filtration was compared, but no difference was found.

[Comparative Example 1] Next, a description will be given of a comparative example in which the leukocyte filter device according to the present invention does not have an overlying structure such as a filter material. In this comparative example, the basis weight of the fibrous structure on the surface of the porous element is only one. Preparation of the fiber was performed in the same manner as in Example 1 above.
The same porous element as that of Example 1 was used as the substrate. When the fiber dispersion was made into paper so that the basis weight of Bemberg fibers was 0.2 g / m ^{2 on} one surface of the polyester nonwoven fabric, the average pore diameter of the porous element having a fiber structure on the surface was 9 μm.

In preparing the filter material, six pre-filters having an average pore diameter of 130 μm, two porous elements (average weight: 66 g / m ² ) having an average pore diameter of 13 μm were arranged in order from the inlet side to the outlet side. ^Two porous elements having a pore size of 10 μm (basis weight 40 g / m ² ) and a basis weight of 0.2 g
A leukocyte removal filter including a stack of 28 porous elements (average pore diameter: 9 μm) having a fibrous structure of / cm ^{2 on} the surface was prepared (filter area: 45 cm ² ). For comparison, the number of each of the prefilter, the nonwoven fabric, and the porous element constituting the filter is the same as that of the filter of the above embodiment. The filter capacity was 18 mL.

When a filtration test was performed in the same manner as in Example 1, the average processing speed was 30 g / min. As a result, the leukocyte residual rate was 10 ^−4.0 and the average processing speed was high, but a satisfactory level of leukocyte removal rate was not obtained. The free hemoglobin before and after the filtration was compared, but no difference was observed. It was found that the blood component was not damaged by the filter material.

[Comparative Example 2] The preparation of the fiber was carried out in the same manner as in Example 1, and the same porous element as the substrate as in Example 1 was used. When the fiber dispersion was paper-made such that the basis weight of Bemberg fibers was 0.5 g / m ² with respect to one surface of the polyester nonwoven fabric, the average pore diameter of the porous element having a fiber structure on the surface was 8 μm.

In preparing the filter material, in order from the inlet side to the outlet side, six pre-filters having an average pore diameter of 130 μm, two porous elements having an average pore diameter of 13 μm (basis weight: 66 g / m ² ), and ^Two porous elements having a pore size of 10 μm (basis weight 40 g / m ² ) and a basis weight of 0.5 g
/ Porous element having fiber structure on the surface of the m ² was prepared leukocyte-removing filter containing a laminate of 28 sheets (average pore size 8 [mu] m) (filter area 45cm ^2). The filter capacity was set to 18 mL, and the coating treatment was performed in the same manner as in Example 1.

When a filtration test was performed in the same manner as in Example 1, the average processing speed was as low as 10 g / min. As a result, the leukocyte residual rate was 10 ^−5.0 , and a satisfactory level of leukocyte removal rate was not obtained. The free hemoglobin before and after filtration was compared, but no difference was found.

[0075]

The leukocyte-removing filter device and leukocyte-removing method of the present invention can simultaneously achieve high leukocyte-removing ability and high average processing speed when removing leukocytes that cause side effects of blood transfusion from a leukocyte-containing liquid. Since a high recovery rate of useful blood components is obtained and the damage to the useful blood components is small, it is very useful as a leukocyte removal filter device and a leukocyte removal method used at the time of blood transfusion.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view schematically showing a porous element substrate used as a filter material of a leukocyte removal filter device according to the present invention. FIG. 1B is a simplified cross-sectional view showing a state in which the fibrous structure is held on the surface of the porous element substrate shown in FIG. 1A. FIG. 1C is a cross-sectional view schematically showing a part of a filter material including the porous element layer shown in FIG. 1B.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Porous element base material, 2 ... Fiber structure, 3 ... Layer of porous element having fiber structure, 4 ... Filter material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 71/06 B01D 71/06 4L047 B32B 5/26 B32B 5/26 D04H 1/42 D04H 1/42 W / / A61K 35/14 A61K 35/14 Z F term (reference) 4C077 AA12 BB02 BB03 KK11 KK25 LL02 LL15 LL17 MM09 PP02 PP08 PP10 PP12 PP13 PP19 4C087 BB34 DA14 MA66 NA06 ZC80 4D006 HA42 JB01 KB14 MA03A03 MC03 MA03A03 MC03 BA12 BA13 BB02 BB03 BB08 BB10 DA01 DA03 4F100 AJ06 AK01D AK25 AK41 AL01 AL04D BA02 BA03 BA04 BA05 BA10A BA10C BA10D BA25 CC00D DG06A DG06B DG06C AB13A12A13C

Claims (8)

[Claims] 1. A layered filter material including a plurality of layers of a porous element having a fibrous structure on at least the surface thereof, wherein a leukocyte-containing liquid is injected from the upper layer side of the filter material and filtered to the lower layer side. A leukocyte removal filter device from which a liquid is collected, there are a plurality of types of basis weight of the fibrous structure, and a porous element having a fibrous structure having a high basis weight is overlaid so as to be disposed on a lower layer side. A leukocyte removal filter device. 2. The porous element included in the filter material has a plurality of types of average pore diameters, and the porous elements having smaller average pore diameters are layered so as to be arranged on a lower layer side. The leukocyte removal filter device according to claim 1. 3. The leukocyte removal filter device according to claim 1, wherein each of the porous elements included in the filter material is a porous element having an average pore diameter of 1 μm or more and less than 100 μm. 4. The porous element having a fiber structure on at least the surface thereof, wherein each of the porous elements has an average fiber diameter of 0.03 μm or more and less than 1 μm. The leukocyte removal filter device according to any one of claims 1 to 3, wherein: Wherein said filter material having a basis weight and a first porous element having at least on the surface of the first fibrous structure of less than 0.1 g / m ² or more 1.0 g / m ^2, the first disposed on the upper layer of the porous element, the basis weight having the first at least the surface of the second fibrous structure is low and less than 0.01 g / m ² or more 0.3 g / m ² than the fiber structure The leukocyte removal filter device according to any one of claims 1 to 4, comprising: a porous element (2); 6. An average pore diameter of the first fibrous structure is 1 μm.
m or more and less than 10 μm, and the average pore diameter of the second fibrous structure is 3 μm or more and 10 μm or more.
The third layer, which is less than and larger than the average pore size of the first fiber structure, does not hold the fiber structure in the upper layer of the second fiber structure, and has an average pore size of 10 μm or more and less than 100 μm. The leukocyte removal filter device according to claim 5, wherein a porous element is arranged. 7. The leukocyte removal filter device according to claim 1, wherein the surface of the filter material is coated with a graft polymer or a polymer material. 8. Using the leukocyte removal filter device according to any one of claims 1 to 7, injecting a leukocyte-containing liquid from the upper layer side of the filter material and collecting the liquid filtered to the lower layer side. Characteristic leukocyte removal method.