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Changes in patterns of Bradykinin generation during leucocyte filtration of platelet concentrates
Transfusion and Apheresis Science 24 (2001) 291±292
www.elsevier.com/locate/transci
Short communication
Changes in patterns of Bradykinin generation during leucocyte ®ltration of platelet concentrates J. Seghatchian a,b,*, P. Krailadsiri a,b a
National Blood Service, Colindale Avenue, Colindale, London NW9 5BG, UK National Blood Service, Crescent Drive, Brentwood, Essex CM15 8DP, UK
b
Received 31 January 2001; accepted 13 February 2001
The passage of platelet concentrates through dierent types of WBC ®lters can lead to variable degrees of activation of kallikrein/kinin system [1±3]. The generation of Bradykinin has been associated with hypotensive reactions in patients receiving angiotensin-converting enzyme inhibitors [4,5]. While the reactions usually occur in the early stage of transfusion, the kinetic of Bradykinin (BK) generation/retention during WBC ®ltration remains unclear. In this respect, it is not known whether the characteristic behaviour of the two types of ®lters in current use are the same. This study was carried out with the following objectives: 1. To compare the eect of negatively and positively charged WBC ®lters on Bradykinin (BK) formation, in a sequential sampling model, using platelet concentrates of the same origin. 2. To compare the characteristic properties of ®ltered platelets obtained from the two types of ®lters, in terms of changes in platelet cellular indices. Platelet concentrates were prepared according to the local SOPs. Filtration was carried out under
* Corresponding author. Tel.: +44-208-258-2700; fax: +44208-258-2970. E-mail address: [email protected] (J. Seghatchian).
standard conditions of head pressure as recommended by the manufacturers. Measurement of Bradykinin (BK): A competitive Elisa technique was employed, using a commercial kit (Markit, Japan). Measurement of platelet cellular indices: Sysmex SE9000 was used for the assessment of platelet count (PLT), mean platelet volume (MPV) and platelet large cell ratio (P-LCR). In all cases (N 6) a hyperbolic pattern of BK generation/retention was observed, with negatively charged ®lters showing higher values of BK (Fig. 1). The level of BK was much higher in apheresis PC as compared to pooled BC±PC. This may be related to the dierences in ratio of anticoagulation, the nature of storage container and the difference in subpopulation of platelet/leucocytes in various products. Moreover, during ®ltration a sharp decrease in platelet count occurred initially, followed by a slow increase to the original count as ®ltration continued, indicating a saturation phenomenon. Negatively charged ®lters appeared to preferentially retain the large platelet subpopulation and aggregates (Fig. 2). Conclusion: The observed hyperbolic pattern re¯ects a saturation phenomenon, followed by a slow rate displacement of BK as ®ltration
1473-0502/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S 1 4 7 3 - 0 5 0 2 ( 0 1 ) 0 0 0 7 2 - 6
292
J. Seghatchian, P. Krailadsiri / Transfusion and Apheresis Science 24 (2001) 291±292
continued. This could be related to the adhesive property of negatively charged platelets and changes in the microenvironment. Both the overall surface charge and the rate of ®ltration may in¯uence the pattern of BK generation/retention [6]. This may account for the controversial reports that the rate of generation/retention of BK on dierent ®lters is variable. The pattern of changes observed in negatively charged ®lters is relevant to transfusion reactions of similar negatively charged ®lters used as bed site. In this respect, the prestorage ®lters will be bene®cial as BK is known to have a short shelf-life. Fig. 1. A representative pattern of BK generation/retention by negatively and positively charged ®lters in platelets.
References [1] Krailadsiri P, Seghatchian J. Negatively charged leucocyte ®lter signi®cantly enhances kallikrein and thrombin-like activities of platelet concentrates. Thromb Res 1996;83: 469±74. [2] Shiba M, Tadokoro K, Sawanobori M, et al. Activation of the contact system by ®ltration of platelet concentrates with a negatively charged white cell-removal ®lter and measurement of venous blood bradykinin level in patients who received ®ltered platelets. Transfusion 1997;37:457±62. [3] Takahashi TA, Abe H, Hosoda M, et al. Bradykinin generation during ®ltration of platelet concentrates with a white cell-reduction ®lter. Transfusion 1995;35:967. [4] Sano H, Koga Y, Hamasaki K, et al. Anaphylaxis associated with white-cell reduction ®lter. Lancet 1996; 347:1053. [5] Mair B, Leparc GF. Hypotensive reactions associated with platelet transfusions and angiotensin-converting enzyme inhibitors. Vox Sang 1998;74:27±30. [6] Snyder E, Mechanic S, Baril L, Davenport RO. Removal of soluble biologic response modi®ers (complement and chemokines) by a bedside white cell-reduction ®lter. Transfusion 1996;36(8):707±13.
Fig. 2. Changes in platelet count, MPV and large platelet subpopulation subsequent to passage through negatively and positively charged ®lters.
www.elsevier.com/locate/transci
Short communication
Changes in patterns of Bradykinin generation during leucocyte ®ltration of platelet concentrates J. Seghatchian a,b,*, P. Krailadsiri a,b a
National Blood Service, Colindale Avenue, Colindale, London NW9 5BG, UK National Blood Service, Crescent Drive, Brentwood, Essex CM15 8DP, UK
b
Received 31 January 2001; accepted 13 February 2001
The passage of platelet concentrates through dierent types of WBC ®lters can lead to variable degrees of activation of kallikrein/kinin system [1±3]. The generation of Bradykinin has been associated with hypotensive reactions in patients receiving angiotensin-converting enzyme inhibitors [4,5]. While the reactions usually occur in the early stage of transfusion, the kinetic of Bradykinin (BK) generation/retention during WBC ®ltration remains unclear. In this respect, it is not known whether the characteristic behaviour of the two types of ®lters in current use are the same. This study was carried out with the following objectives: 1. To compare the eect of negatively and positively charged WBC ®lters on Bradykinin (BK) formation, in a sequential sampling model, using platelet concentrates of the same origin. 2. To compare the characteristic properties of ®ltered platelets obtained from the two types of ®lters, in terms of changes in platelet cellular indices. Platelet concentrates were prepared according to the local SOPs. Filtration was carried out under
* Corresponding author. Tel.: +44-208-258-2700; fax: +44208-258-2970. E-mail address: [email protected] (J. Seghatchian).
standard conditions of head pressure as recommended by the manufacturers. Measurement of Bradykinin (BK): A competitive Elisa technique was employed, using a commercial kit (Markit, Japan). Measurement of platelet cellular indices: Sysmex SE9000 was used for the assessment of platelet count (PLT), mean platelet volume (MPV) and platelet large cell ratio (P-LCR). In all cases (N 6) a hyperbolic pattern of BK generation/retention was observed, with negatively charged ®lters showing higher values of BK (Fig. 1). The level of BK was much higher in apheresis PC as compared to pooled BC±PC. This may be related to the dierences in ratio of anticoagulation, the nature of storage container and the difference in subpopulation of platelet/leucocytes in various products. Moreover, during ®ltration a sharp decrease in platelet count occurred initially, followed by a slow increase to the original count as ®ltration continued, indicating a saturation phenomenon. Negatively charged ®lters appeared to preferentially retain the large platelet subpopulation and aggregates (Fig. 2). Conclusion: The observed hyperbolic pattern re¯ects a saturation phenomenon, followed by a slow rate displacement of BK as ®ltration
1473-0502/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S 1 4 7 3 - 0 5 0 2 ( 0 1 ) 0 0 0 7 2 - 6
292
J. Seghatchian, P. Krailadsiri / Transfusion and Apheresis Science 24 (2001) 291±292
continued. This could be related to the adhesive property of negatively charged platelets and changes in the microenvironment. Both the overall surface charge and the rate of ®ltration may in¯uence the pattern of BK generation/retention [6]. This may account for the controversial reports that the rate of generation/retention of BK on dierent ®lters is variable. The pattern of changes observed in negatively charged ®lters is relevant to transfusion reactions of similar negatively charged ®lters used as bed site. In this respect, the prestorage ®lters will be bene®cial as BK is known to have a short shelf-life. Fig. 1. A representative pattern of BK generation/retention by negatively and positively charged ®lters in platelets.
References [1] Krailadsiri P, Seghatchian J. Negatively charged leucocyte ®lter signi®cantly enhances kallikrein and thrombin-like activities of platelet concentrates. Thromb Res 1996;83: 469±74. [2] Shiba M, Tadokoro K, Sawanobori M, et al. Activation of the contact system by ®ltration of platelet concentrates with a negatively charged white cell-removal ®lter and measurement of venous blood bradykinin level in patients who received ®ltered platelets. Transfusion 1997;37:457±62. [3] Takahashi TA, Abe H, Hosoda M, et al. Bradykinin generation during ®ltration of platelet concentrates with a white cell-reduction ®lter. Transfusion 1995;35:967. [4] Sano H, Koga Y, Hamasaki K, et al. Anaphylaxis associated with white-cell reduction ®lter. Lancet 1996; 347:1053. [5] Mair B, Leparc GF. Hypotensive reactions associated with platelet transfusions and angiotensin-converting enzyme inhibitors. Vox Sang 1998;74:27±30. [6] Snyder E, Mechanic S, Baril L, Davenport RO. Removal of soluble biologic response modi®ers (complement and chemokines) by a bedside white cell-reduction ®lter. Transfusion 1996;36(8):707±13.
Fig. 2. Changes in platelet count, MPV and large platelet subpopulation subsequent to passage through negatively and positively charged ®lters.