JPH0534337A - Filter for separating leucocyte - Google Patents

Abstract

PURPOSE:To separate leucocytes in blood efficiently and safely by using a porous body of a three-dimensional mesh-shaped continuous structure having continuous open pores as a filter. CONSTITUTION:A filter 1 for separating leucocytes has a construction wherein a porous body 5 formed of polyvinyl formal or polyurethane resin is supported by supporting materials 6a and 6b in a housing 4 having a blood inflow port 2 and a blood outflow port 3. The porous body 5 being the main component of the filter is constructed of a three-dimensional mesh-shaped continuous structure having continuous open pores of most frequent pore diameters 1 to 5mum. The diameters of the continuous open pores are 2 to 4mum desirably in view of clogging and a leucocyte retention rate, and the porosity rate is 75 to 95% desirably in view of the strength of the filter and a speed of separation. Since the flow passage of the filter is formed at the time when the porous body 5 is molded, nonuniformity is little and the possibility of an extraneous substance flowing out at the time of an operation is small. On the occasion of separation of the leucocytes, priming is made by a physiological saline solution and then the leucocytes out of blood constituents are retained by the porous body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leukocyte separating filter. More specifically, the present invention relates to a leukocyte separation filter which has a stable capturing ability for leukocytes and which is free from the possibility of contamination by foreign matter.

[0002]

2. Description of the Related Art The form of blood transfusion has long changed from conventional whole blood transfusion to component transfusion in which only the components required by the patient are transfused. In this component transfusion, the purity of the fractionated blood components is changed. The issue is how to raise it. Conventionally, blood obtained by donating blood is separated into concentrated red blood cell liquid (CRC), concentrated platelet plasma (PC) and platelet poor plasma (PPP) by centrifugation. The blood cell preparation thus separated is widely used for component transfusion to patients who need red blood cells or platelets, but each blood cell preparation contains many white blood cells, and a large amount of white blood cells is produced by the blood transfusion. It is regarded as a problem that it is infused. Leukocytes contained in blood cell preparations need to be removed as much as possible in order to prevent side effects after blood transfusion, and for this reason, many innovations have been made in the past. As the method, there are used a gravity centrifugation method utilizing a difference in specific gravity of blood cells, a method utilizing a capturing material utilizing an action such as adhesion or adhesion of leukocytes, and the like.

Among these methods, the method of using a capturing material is widely used because of its excellent leukocyte removal efficiency and simple procedure, and there are capturing materials such as natural fibers and synthetic fibers, which have a large fiber diameter. In many cases, very small fibers packed in the column as they are or secondary processed into a non-woven fabric are used. However, when such a fiber is used, there is an unavoidable risk of the fiber falling off during the operation, and there is a risk of foreign matter outflow.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel leukocyte separation filter. Another object of the present invention is to provide a leukocyte separation filter that has a high and stable capturing ability for leukocytes and that can efficiently separate leukocytes from blood. A further object of the present invention is to provide a leukocyte separation filter that can safely perform leukocyte separation operation without the risk of foreign matter flowing out during operation. Another object of the present invention is to provide a filter for separating leukocytes, which simplifies the manufacturing process of the filter and has less variation in product performance.

[0005]

[Means for Solving the Problems] The above-described objects are achieved by a leukocyte separation filter comprising a porous body having a three-dimensional reticulated continuous tissue having continuous open pores having a most frequent (most) pore diameter of 1 to 5 μm. .

The present invention is a leukocyte separating filter in which a porous body is made of vinyl formal or polyurethane resin.

[0007]

The white blood cell separation filter of the present invention is characterized by comprising a porous body having a three-dimensional network continuous structure having continuous open pores having a most frequent (most frequent) pore diameter of 1 to 5 μm.

When a leukocyte suspension such as blood is treated with a porous body having a pore size within a certain range as described above in which the matrix is a three-dimensional network continuous tissue, leukocytes contained in the suspension are treated. , Is efficiently trapped while passing through a complicated flow path composed of continuous open pores formed between the matrices of the porous body. Furthermore, since the flow path of the filter is a three-dimensional network continuous structure of the porous body, that is, continuous open pores formed by the matrix of the porous body, the flow path of the filter is formed during the molding of the porous body. Therefore, the production process for producing a leukocyte separation filter using the porous body is extremely simple, and the variation in product performance is stable because it is a continuous structure, and Problems such as the outflow of foreign matter from the body and channel channeling do not essentially occur.

Hereinafter, the present invention will be described in more detail based on the embodiments.

The leukocyte separating filter of the present invention comprises a porous body having a continuous three-dimensional network structure having continuous open pores, and the material of the porous body is polyvinyl formal or polyurethane resin.

In the porous body having the above-mentioned structure according to the present invention, the most frequent (most) pore size of continuous open pores is 1 to.
It is desirable that the thickness is 5 μm, preferably 2 to 4 μm.
That is, if the pore diameter is less than 1 μm, the blood to be treated or other blood cells contained in the leukocyte suspension may be captured during the leukocyte removal operation, which may cause clogging. On the other hand, when the pore diameter is more than 5 μm, the frequency of contact with the leukocyte suspension to be treated is reduced, which may reduce the leukocyte capture rate.

The "most frequent (most) pore diameter" in the present invention is a diameter obtained by cutting a porous body arbitrarily, measuring the area of each of the pores dispersed in the entire cross section, and converting it into a circle. When the relationship between the diameter and the number of pores is determined by finding the value, the diameter converted into a circle represents the most number. That is, the pores dispersed on any cut surface of the porous body have various shapes and have various diameters, but each pore is converted into a circle having the same area as the cross-sectional area of the pore, and its diameter is 1
When a curve is drawn on a graph with the horizontal axis at μm intervals and the number of pores (every 1 μm) in that section on the vertical axis, the diameter at the peak of the curve is the mode ( (Most) pore size. At this time, the pores are randomly set to 2,0
It is preferable to count 00 or more. Therefore, the number of pores having the most frequent (most) diameter or more means that the number is small, and it does not mean that particles having a diameter larger than this do not pass through.

The porosity of such a porous material depends on the most frequent (most) pore diameter and the like, but is 75 to 95.
%, And more preferably 80 to 95%. That is, when the porosity is 75% or more, the leukocyte removal treatment operation can be performed in a shorter time, while when the porosity is 95% or less, the strength of the filter is excellent. Further, the thickness of such a porous body depends on the most frequent (most) pore diameter, the porosity, the fine structure of the three-dimensional network continuous structure which is a matrix, and the like, but is more preferably 0.1 to 10 mm. Is preferably about 0.5 to 3 mm. That is, when the thickness of the porous body is 0.1 mm or more, the strength of the filter is excellent,
This is because if the thickness is 10 mm or less, the length of the filtration layer does not become too long and the possibility of clogging decreases.

The porous material according to the present invention is not particularly limited in its material as long as it has a desired structure, but it is desired that it is less likely to damage blood cells. Further, depending on the type of blood product or the like to be treated with a filter, for example, when processing a concentrated red blood cell, it is desired that the material to which platelets are likely to adhere is desired, and when treating concentrated platelet plasma, the material to which platelets are unlikely to be adhered. Is desired.

The polyvinyl formal according to the present invention is
It may be obtained by any method as long as it has a desired structure, but starch, polysaccharides containing amylose such as dextrin and derivatives thereof, anionic surfactant having acid resistance, and If necessary, an inorganic salt such as sodium sulfate, sodium chloride, ammonium sulfate, ammonium chloride, potassium sulfate, or sodium iodide is present in an aqueous polyvinyl alcohol solution containing a pore-forming agent such as a nonionic surfactant, and formaldehyde and Those obtained by the elution method (Japanese Patent Publication No. 47-46455 and Japanese Patent Publication No. 48-20019) in which an acetalization reaction is performed by using an acid catalyst are particularly preferable because they have a desired structure.

The polyurethane resin according to the present invention is preferably a synthetic resin foam of polyurethane, or a synthetic resin porous body coated with a material such as segmented polyurethane which does not easily adhere to blood cells.

One embodiment of the leukocyte separation filter of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the leukocyte separation filter of the present invention. In the present embodiment, the leukocyte separation filter 1 has a porous body 5 made of polyvinyl formal or polyurethane resin having the above-described structure in a housing 4 having a blood inlet 2 and a blood outlet 3. It is provided across the internal space. In order to hold the porous body 5 in the housing 4 in such a leukocyte separation filter 1, for example, liquid-permeable support materials 6a and 6b are provided before and after the porous body 5, and the support materials 6a and 6b are provided.
It is optional to sandwich the porous body 5 with. The white blood cell separation filter 1 is actually used by being incorporated in a circuit as shown in FIG. 2, for example. In the circuit shown in FIG. 2, a blood bag 7 containing a blood component to be processed and a physiological saline bag 8 containing physiological saline are positioned above the leukocyte separation filter 1 and are respectively clamps 9a and 9b. Filter 1 for separating white blood cells by liquid guiding tubes 10a and 10b equipped with
, Which is in communication with the blood inlet port 2, while a physiological saline solution collection bag 11 and a blood collection bag 12 for collecting the treated blood component are positioned below the white blood cell separation filter 1. The blood flow outlets 3 of the leukocyte separation filter 1 are communicated with the liquid guide tubes 10c and 10d, which are provided with clamps 9c and 9d, respectively. In the white blood cell separation operation, first, with the clamps 9b and 9c opened and the clamps 9a and 9d closed, physiological saline is flown from the physiological saline bag 8 to the leukocyte separation filter 1 to prime the inside of the leukocyte separation filter 1. The physiological saline used for priming is the saline recovery bag 1
Recovered to 0. After the priming, this time, the clamps 9a and 9d are opened, the clamps 9b and 9c are closed, and blood components are separated from the blood bag 7 by the white blood cell separation filter 1.
Shed on. In the white blood cell separation filter 1, when the blood component passes through the porous body 5 having the above-mentioned configuration, the white blood cell component is adsorbed and captured by the porous body 5 to separate the white blood cells. The blood component from which the white blood cell component has been removed in this manner is recovered in the blood recovery bag 12 in communication therewith. After the blood components have been flushed from the blood bag 7, in order to collect the blood remaining in the leukocyte separation filter 1, the clamp 9b is further opened and physiological saline is again poured into the leukocyte separation filter 1 for leukocyte separation. Blood collection bag 12 that pushes out the blood remaining in the filter 1
And when almost all blood components have been collected, the clamp 9d is closed and the clamp 9c is opened to recover the physiological saline used for blood recovery in the physiological saline recovery bag 11 to complete the leukocyte separation operation. .

[0018]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 A polyvinyl formal porous body having a most frequent (most) pore diameter of 2 to 3 μm and a porosity of 86% had a thickness of 1.3 mm and a filtration area of 1
A white blood cell separation filter as shown in FIG. 1 having a size of 00 cm ² was prepared, and 400 ml of blood was collected on the white blood cell separation filter using the circuit shown in FIG. (CRC) 1 unit was run by natural head. As a result, the time required for the treatment is 6 minutes, and the blood cell count in the CRC before and after the treatment is automatically measured by a blood cell counter (Sysmex NE-6000, Toa Medical Electronics Co., Ltd.).
After the calculation, the absolute number of each blood cell component was calculated based on the liquid volume, and the leukocyte removal rate was calculated from this.
%, The recovery rate of red blood cells was 98%, and the platelet removal rate was 90%.

Example 2 A polyurethane resin porous body having a most frequent (most) pore diameter of 2 to 3 μm and a porosity of 82% had a thickness of 1.0 mm and a filtration area of 50 c.
A white blood cell separation filter as shown in FIG. 1 was prepared for m ² and further 200 ml of blood was collected on the white blood cell separation filter using the circuit as shown in FIG. 10 units of PC) was flown at an infusion rate (about 4 ml / min.). As a result, the dropping rate does not slow down, and the blood cell counts in the PC before and after the treatment are automatically measured with a blood cell counter (Sysmex NE-6000, manufactured by Toa Medical Electronics Co., Ltd.) and a flow cytometer (Cyto-ACE1).
50, manufactured by JASCO Corporation, the absolute number of each blood cell component was calculated based on the liquid volume, and the leukocyte removal rate was calculated from the absolute number, which was 99.9%, and the platelet recovery rate was also calculated. Was 95%.

[0021]

As described above, the present invention is a leukocyte separation filter comprising a porous body having a three-dimensional reticulated continuous tissue having continuous open pores having a most frequent (most) pore diameter of 1 to 5 μm. It has a high and stable capturing ability for leukocytes, and can efficiently separate leukocyte components from leukocyte suspensions such as blood, and there is no fear of contamination by foreign substances due to the dropping of the filter medium during operation, It is possible to safely perform leukocyte removal operation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a leukocyte separation filter of the present invention.

FIG. 2 is a circuit diagram showing a blood processing circuit incorporating an embodiment of the leukocyte separation filter of the present invention.

[Explanation of symbols]

1 ... Leukocyte separation filter, 2 ... Blood inlet, 3 ... Blood outlet, 4 ... Housing, 5 ... Polyvinyl formal porous body, 6a, 6b ... Support material, 7 ... Blood bag, 8 ... Saline solution bag, 9a , 9b, 9c, 9d ... Clemme,
10a, 10b, 10c, 10d ... Liquid conducting tube, 11
... Saline saline bag, 12 ... Blood bag.

Claims (3)

[Claims] 1. A filter for separating leukocytes comprising a porous body having a continuous three-dimensional network structure having continuous open pores having a most frequent (most frequent) pore diameter of 1 to 5 μm. 2. The leukocyte separation filter according to claim 1, wherein the porous body is made of polyvinyl formal. 3. The leukocyte separation filter according to claim 1, wherein the porous body is made of a polyurethane resin.