Reagent and method for classifying leucocytes

1. A reagent for classifying leucocytes, wherein said reagent comprises;

a) a surfactant for lysing erythrocytes and partly damaging cell membrane of leucocytes, wherein the only said surfactant in the reagent is at least one of the surfactants selected from the group consisting of a cationic surfactant, an amphoteric surfactant, and the combination thereof,

b) an organic compound having phenyl or heterocyclic group, wherein when said surfactant is a cationic surfactant, said organic compound is an organic compound having an anionic group; when said surfactant is an amphoteric surfactant or a combination of amphotheric and cationic surfactants, said organic compound is an organic compound having an anionic or cationic group; and

c) a buffer for adjusting pH.

2. The reagent for classifying leucocytes according to claim 1 , wherein said reagent further comprises an alcohol.

3. The reagent for classifying leucocytes according to claim 2 , wherein the cationic surfactant is at least one of the quaternary ammonium salts represented by formula I,

wherein R 1 is C 6-14 alkyl or C 6-14 alkenyl; R 2 and R 3 are independently C 1-4 alkyl or C 1-4 alkenyl; R 4 is C 1-4 alkyl, C 1-4 alkenyl, or benzyl; and X is a halogen atom.

4. The reagent for classifying leucocytes according to claim 3 , wherein R 1 is hexyl, octyl, decyl or dodecyl; R 2 and R 3 are independently methyl, ethyl or propyl.

5. The reagent for classifying leucocytes according to claim 2 , wherein the amphoteric surfactant is at least one of those represented by formula II,

wherein R 5 is C 6-14 alkyl or C 6-14 alkenyl; R 6 and R 7 are independently C 1-4 alkyl or C 1-4 alkenyl.

6. The reagent for classifying leucocytes according to claim 5 , wherein R 5 is hexyl, octyl, decyl or dodecyl; R 6 and R 7 are independently methyl, ethyl or propyl.

7. The reagent for classifying leucocytes according to claim 2 , wherein said reagent further comprises at least one of acidic organic compounds and/or pigments.

8. The reagent for classifying leucocytes according to claim 7 , wherein the cationic surfactant is at least one of the quaternary ammonium salts represented by formula I,

wherein R 1 is C 6-14 alkyl or C 6-14 alkenyl; R 2 and R 3 are independently C 1-4 alkyl or C 1-4 alkenyl; R 4 is C 1-4 alkyl, C 1-4 alkenyl, or benzyl; and X is a halogen atom.

9. The reagent for classifying leucocytes according to claim 8 , wherein R 1 is hexyl, octyl, decyl or dodecyl; R 2 and R 3 are independently methyl, ethyl or propyl.

10. The reagent for classifying leucocytes according to claim 7 , wherein the amphoteric surfactant is at least one of those represented by formula II,

wherein R 5 is C 6-14 alkyl or C 6-14 alkenyl; R 6 and R 7 are independently C 1-4 alkyl or C 1-4 alkenyl.

11. The reagent for classifying leucocytes according to claim 10 , wherein R 5 is hexyl, octyl, decyl or dodecyl; R 6 and R 7 are independently methyl, ethyl or propyl.

12. The reagent for classifying leucocytes according to claim 1 , wherein said buffer is a buffer for adjusting the pH of the reagent within the range of from 2 to 6.

13. The reagent for classifying leucocytes according to claim 12 , wherein the cationic surfactant is at least one of the quaternary ammonium salts represented by formula I,

wherein R 1 is C 6-14 alkyl or C 6-14 alkenyl; R 2 and R 3 are independently C 1-4 alkyl or C 1-4 alkenyl; R 4 is C 1-4 alkyl, C 1-4 alkenyl, or benzyl; and X is a halogen atom.

14. The reagent for classifying leucocytes according to claim 13 , wherein R 1 is hexyl, octyl, decyl or dodecyl; R 2 and R 3 are independently methyl, ethyl or propyl.

15. The reagent for classifying leucocytes according to claim 12 , wherein the amphoteric surfactant is at least one of those represented by formula II,

wherein R 5 is C 6-14 alkyl or C 6-14 alkenyl; R 6 and R 7 are independently C 1-4 alkyl or C 1-4 alkenyl.

16. The reagent for classifying leucocytes according to claim 15 , wherein R 5 is hexyl, octyl, decyl or dodecyl; R 6 and R 7 are independently methyl, ethyl or propyl.

17. The reagent for classifying leucocytes according to claim 1 , wherein the cationic surfactant is at least one of the quaternary ammonium salts represented by formula I,

wherein R 1 is C 6-14 alkyl or C 6-14 alkenyl; R 2 and R 3 are independently C 1-4 alkyl or C 1-4 alkenyl; R 4 is C 1-4 alkyl, C 1-4 alkenyl, or benzyl; and X is a halogen atom.

18. The reagent for classifying leucocytes according to claim 17 , wherein R 1 is hexyl, octyl, decyl or dodecyl; R 2 and R 3 are independently methyl, ethyl or propyl.

19. The reagent for classifying leucocytes according to claim 1 , wherein the amphoteric surfactant is at least one of those represented by formula II,

wherein R 5 is C 6-14 alkyl or C 6-14 alkenyl; R 6 and R 7 are independently C 1-4 alkyl or C 1-4 alkenyl.

20. The reagent for classifying leucocytes according to claim 19 , wherein R 5 is hexyl, octyl, decyl or dodecyl; R 6 and R 7 are independently methyl, ethyl or propyl.

21. A method for classifying leukocytes using the reagent according to claim 1 , comprising steps of adding said reagent to a whole blood sample for classifying leukocytes into four groups consisting of three groups corresponding to lymphocytes, monocytes and eosinophils and one group corresponding to neutrophils and basophils, and counting each group by measuring the size and the shape thereof, wherein the measurement of the size of the cells is performed by using laser scattering with a low angle scattered light at a measurement angle ranging from 2 to 6 degrees and the measurement of the shape of the cells is performed by using laser scattering with a high angle scattered light at a measurement angle ranging from 8 to 20 degrees; wherein a scattergram produced by counting each group using low angle scattered light and high angle scattered light provides the monocyte group spaced apart from the remaining leukocyte groups.

22. A reagent for classifying leucocytes, said reagent consisting essentially of:

a) a surfactant for lysing erythrocytes and partly damaging cell membrane of leucocytes, said surfactant is at least one of the surfactants selected from the group consisting of a cationic surfactant, an amphoteric surfactant, and the combination thereof,

b) an organic compound having phenyl or heterocyclic group, wherein when said surfactant is a cationic surfactant, said organic compound is an organic compound having an anionic group; when said surfactant is an amphoteric surfactant or a combination of amphoteric and cationic surfactants, said organic compound is an organic compound having an anionic or cationic group;

c) a buffer for adjusting pH; and

d) optionally, an alcohol, an acidic organic compound and/or pigments.