Quenching methods for red blood cell pathogen inactivation

1. A method of treating a red blood cell composition comprising:

(a) mixing

(i) an effective amount of a pathogen-inactivating compound comprising a functional group which is, or which forms, a reactive electrophilic group;

(ii) an effective amount of a quencher comprising a thiol group, wherein the thiol is capable of reacting with the reactive electrophilic group of the pathogen-inactivating compound;

(iii) a composition comprising red blood cells; and

(iv) about 0.5 to 1.5 equivalents of base, wherein an equivalent means a molar amount that is equivalent to the molar amount of quencher in the mixture;

in a treatment solution or diluent solution;

wherein the treatment solution or diluent solution comprises one or more of dextrose, adenine, mannitol, citrate, and citric acid; and

wherein the mixture of step (a) after addition of the treatment solution or diluent solution comprises between about 40 mM and 100 mM chloride ion;

(b) replacing the solution used during treatment of the red blood cell composition in step (a) with a final additive solution, such that the concentration of the quencher in the mixture is decreased to less than about 10 mM,

wherein the level of dehydration of the treated red blood cell composition is decreased relative to the level of dehydration of a red blood cell composition treated according to a method comprising step (a), but excluding step (b) and/or with 2.0 or greater equivalents of base.

2. The method of claim 1 , wherein the base is of sufficient amount to reduce the level of an unwanted reaction of the pathogen-inactivating compound with red blood cells in the mixture, relative to the mixture without the base.

3. The method of claim 1 , wherein the treatment solution comprises one or more of phosphate and chloride.

4. The method of claim 1 , wherein the diluent solution comprises phosphate.

5. The method of claim 1 , wherein the composition comprising red blood cells (iii) further comprises an additive solution.

6. The method of claim 2 , wherein the unwanted reaction of the pathogen-inactivating compound with red blood cells is modification of the red blood cells by the pathogen-inactivating compound.

7. The method of claim 1 , wherein the base and the quencher are mixed with the red blood cell composition prior to, at the same time, or no more than about 30 minutes after mixing the pathogen-inactivating compound with the red blood cell composition.

8. The method of claim 1 , wherein the base and the quencher are mixed together prior to mixing either the base or the quencher with the red blood cell composition.

9. The method of claim 1 , wherein the base is NaOH.

10. The method of claim 1 wherein the base comprises about 0.75 to 1.25 equivalents of base, wherein an equivalent means a molar amount that is equivalent to the molar amount of quencher in step (a) of the mixture.

11. The method of claim 1 , wherein the base comprises about 1 equivalent of base, wherein an equivalent means a molar amount that is equivalent to the molar amount of quencher in step (a) of the mixture.

12. The method of claim 1 , wherein the resulting mixture of step (a) has a pH at 37° C. of about 6.5 to 7.1.

13. The method of claim 1 , wherein the quencher comprises cysteine or a derivative of cysteine.

14. The method of claim 1 , wherein the quencher is glutathione or a pharmaceutically acceptable salt thereof.

15. The method of claim 1 , wherein the quencher is glutathione monosodium salt.

16. The method of claim 1 , wherein the concentration of the quencher in the resulting mixture of step (a) is greater than 2 mM.

17. The method of claim 1 , wherein the quencher in the resulting mixture of step (a) is at a concentration of about 5 mM to about 30 mM.

18. The method of claim 1 , wherein the quencher in the resulting mixture of step (a) is at a concentration of about 15 mM to about 25 mM.

19. The method of claim 1 , wherein the quencher in the resulting mixture of step (a) is at a concentration of about 20 mM.

20. The method of claim 1 , wherein replacing the solution used during treatment of the red blood cell composition in step (a) with a final additive solution comprises centrifugation of the mixture followed by removal of the supernatant of the mixture.

21. The method of claim 1 , wherein replacing the solution used during treatment of the red blood cell composition in step (a) with a final additive solution comprises size-exclusion separation.

22. The method of claim 1 , wherein replacing the solution used during treatment of the red blood cell composition in step (a) with a final additive solution comprises use of expression devices.

23. The method of claim 1 , wherein the quencher in the resulting mixture of step (b) is at a concentration of less than about 8 mM.

24. The method of claim 1 , wherein the quencher in the resulting mixture of step (b) is at a concentration of less than about 6 mM.

25. The method of claim 1 , wherein the functional group is selected from the group consisting of a mustard, a mustard intermediate, and a mustard equivalent.

26. The method of claim 1 , wherein the functional group is, or is capable of forming, an aziridinium ion.

27. The method of claim 1 , wherein the reactive electrophilic group is capable of reacting with nucleic acids.

28. The method of claim 1 , wherein the pathogen-inactivating compound further comprises a nucleic acid binding ligand.

29. The method of claim 28 , wherein the nucleic acid binding ligand is an intercalator.

30. The method of claim 29 , wherein the intercalator is an acridine.

31. The method claim 28 , wherein the pathogen-inactivating compound comprises a frangible linker linking the functional group and the nucleic acid binding ligand.

32. The method of claim 1 , wherein the pathogen-inactivating compound is

β-alanine, N-(acridin-9-yl), 2-[bis(2-chloroethyl)amino]ethyl ester.

33. The method of claim 1 , wherein the concentration of the pathogen-inactivating compound in the resulting mixture of step (a) is about 0.1 μM to about 5 mM.

34. The method of claim 1 , wherein the concentration of the pathogen-inactivating compound in the resulting mixture of step (a) is sufficient to inactivate at least 3 logs of a pathogen in the red blood cell composition, if present.

35. The method of claim 1 , wherein the time between step (a) and step (b) is about 1 to 48 hours.

36. The method of claim 1 , wherein the time between step (a) and step (b) is about 4 to 30 hours.

37. The method of claim 1 , wherein the treatment inactivates at least 3 logs of a pathogen contaminant in the red blood cell composition, if present.

38. The method of claim 1 , further comprising the step of decreasing the concentration of the pathogen-inactivating compound in the mixture.

39. The method of claim 38 , wherein the steps of decreasing the concentration of the quencher in the mixture and decreasing the concentration of the pathogen-inactivating compound in the mixture occur at the same time.

40. The method of claim 1 , wherein the final additive solution comprises one or more of dextrose, sodium chloride, adenine, guanosine, glucose, citrate, citric acid, phosphate, and mannitol.

41. The method of claim 1 , wherein following step (a), the red blood cells of the resulting mixture have an anti-pathogen inactivating compound antibody binding capacity (ABC) of less than 55% compared to the ABC value of red blood cells from the same method under the same conditions, but without the base.

42. The method of claim 1 , wherein at 20 hours following step (a), the red blood cells of the resulting mixture have an anti-pathogen inactivating compound antibody binding capacity (ABC) of less than 65% compared to the ABC value of red blood cells from the same method under the same conditions, but without the use of base.

43. The method of claim 1 , wherein the red blood cells of the resulting mixture have an average anti-pathogen inactivating compound antibody binding capacity (ABC) of less than about 50,000.

44. The method of claim 1 , wherein the red blood cells of the resulting mixture have an average anti-pathogen inactivating compound antibody binding capacity (ABC) of less than about 40,000.

45. The method of claim 1 , wherein the red blood cells of the resulting mixture have an average anti-pathogen inactivating compound antibody binding capacity (ABC) of between about 25,000 and 70,000.

46. The method of claim 1 , wherein the red blood cells of the resulting mixture have an average anti-pathogen inactivating compound antibody binding capacity (ABC) of between about 35,000 and 45,000.

47. The method of claim 1 , wherein the red blood cells of the resulting mixture have less than 1% hemolysis following step (b).

48. The method of claim 1 , wherein the red blood cells of the resulting mixture have less than 1% hemolysis at a time of 42 days at 4° C. following step (b).

49. The method of claim 1 , wherein the red blood cells of the resulting mixture have a Packed Cell Volume of greater than 50% following step (b).

50. The method of claim 1 , wherein the red blood cells of the resulting mixture have a Packed Cell Volume of greater than 50% at a time of 42 days at 4° C. following step (b).

51. The method of claim 1 , wherein the red blood cells of the resulting mixture have a Median Corpuscular Fragility value greater than 140 mOsm after 42 days at 4° C. following step (b).

52. The method of claim 8 , wherein mixing the base and the quencher results in a salt form of the quencher.

53. The method of claim 52 , wherein the quencher is glutathione, and the salt form is potassium glutathione or sodium glutathione.

54. The method of claim 1 , wherein the mixture of step (a) after addition of the treatment solution or diluent solution and prior to step (b) comprises less than about 75 mM chloride ion.

55. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 70% and 90%.

56. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 75% and 85%.

57. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 50 and 70%.

58. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 55 and 75%.

59. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 30 and 50%.

60. The method of claim 1 , wherein the composition comprising red blood cells in step (a) has a Packed Cell Volume of between about 35 and 45%.

61. The method of claim 1 , wherein the red blood cells in step (a) have been leukoreduced.

62. The method of claim 1 , the red blood cells in step (a) have not been leukoreduced.

63. The method of claim 1 , wherein the resulting mixture of step (a) has a pH at 37° C. of about 6.0 to 7.5.

64. The method of claim 1 , wherein the resulting mixture of step (a) has a pH at 37° C. of about 6.8.

65. The method of claim 1 , wherein the concentration of the pathogen-inactivating compound in the resulting mixture of step (a) is sufficient to inactivate at least 1 log of a pathogen in the red blood cell composition, if present.

66. The method of claim 1 , wherein the treatment inactivates at least 1 log of a pathogen contaminant in the red blood cell composition, if present.

67. A method of reducing dehydration in a red blood cell composition wherein the composition is a mixture comprising (a) a quencher capable of reacting with a pathogen-inactivating compound, (b) about 0.5 to 1.5 equivalents of base, wherein an equivalent means a molar amount that is equivalent to the molar amount of quencher in the mixture, (c) red blood cells, and (d) a treatment solution or diluent solution; wherein the treatment solution or diluent solution comprises one or more of dextrose, adenine, mannitol, citrate, and citric acid; and wherein the red blood cell composition comprises between about 40 mM and 100 mM chloride ion; the method comprising replacing the solution in the mixture with a final additive solution, such that the concentration of the quencher in the mixture is decreased to less than about 10 mM; wherein the level of dehydration of the red blood cell composition is decreased relative to the level of dehydration of a red blood cell composition comprising (a), (c), (d), and 2.0 or greater equivalents of base and in which the solution in the mixture has not been replaced with a final additive solution.

68. The method of claim 67 , wherein the quencher comprises cysteine or a derivative of cysteine.

69. The method of claim 67 , wherein the quencher is glutathione or a pharmaceutically acceptable salt thereof.

70. The method of claim 67 , wherein the quencher is glutathione monosodium salt.

71. The method of claim 67 , wherein the concentration of the quencher is decreased to less than about 8 mM.

72. The method of claim 67 , wherein the concentration of the quencher is decreased to less than about 6 mM.

73. The method of claim 67 , wherein the red blood cells of the mixture after decreasing the concentration of the quencher have less than 1% hemolysis.

74. The method of claim 73 , wherein the red blood cells of the mixture after decreasing the concentration of the quencher have less than 1% hemolysis at a time of 42 days at 4° C.

75. The method of claim 67 , wherein the red blood cells of the mixture after decreasing the concentration of the quencher have a Packed Cell Volume of greater than 50%.

76. The method of claim 75 , wherein the red blood cells of the mixture after decreasing the concentration of the quencher have a Packed Cell Volume of greater than 50% at a time of 42 days at 4° C.

77. The method of claim 67 , wherein the red blood cells of the mixture after decreasing the concentration of the quencher have a Median Corpuscular Fragility value greater than 140 after 42 days at 4° C.