Stabilization of von Willebrand factor in banked blood by leucocyte depletion

Cold storage of citrated whole blood induces drastic time-dependent losses in factor VIII and von Willebrand factor: potential for misdiagnosis of haemophilia and von Willebrand disease

This study investigates the effect of pre-analytic storage conditions on the laboratory evaluation of von Willebrand disease (VWD) and haemophilia. Samples from healthy controls and patients with VWD were stored as whole blood and as separated plasma, both at room temperature and on crushed ice, for two different time periods (3 or 6 h). In samples from healthy individuals (n=10) and in patients with suspected type 1 VWD (n=10), storage of whole blood on ice caused a drastic time-dependent decrease in von Willebrand factor (VWF):ristocetin cofactor activity, in VWF:antigen activity and factor VIII activity (mean+/-SD) to 35+/-18, 55+/-23 and 53+/-15% of baseline levels after 6 h storage, respectively. Patients with type 2 VWD and non-detectable VWF:ristocetin cofactor activity did not demonstrate such drastic cold-induced losses in VWF and factor VIII levels. Storage of plasma caused only minor changes in VWF levels. The cold-induced loss in VWF might thus depend on the presence of platelets and of high molecular weight VWF. Chilling of platelets induces a clustering of the glycoprotein Ib subunit. We therefore hypothesize that cold-induced loss in VWF might be due to a cold-promoted binding of VWF to glycoprotein VWF receptor Ib alpha. These results suggest a serious potential for misdiagnosis of haemophilia or VWD due to inappropriate pre-analytical handling of blood.

Leucodepletion leads to component-like storage stability of whole blood - suggesting its homologous use?

BACKGROUND AND OBJECTIVES

Leucodepleted whole blood (LWB) is already widely used for autologous donations and could also be appropriate for certain instances of allogeneic transfusion provided that storage quality can be preserved at component-like levels.

MATERIALS AND METHODS

Sixteen units of whole blood (WB), donated by healthy volunteers into CPDA-1 according to German guidelines, were leucofiltered prestorage and stored for up to 49 days. Unfiltered WB in CPDA-1 (UFWB, n=16) and filtered red blood cells in SAGM (RCC, n=14) served as controls. Several haematological, biochemical and coagulatory quality parameters were determined at designated time-points during storage.

RESULTS

Apart from significant differences (P<0.05) in haematocrit (56.2+/-3.6 vs. 37.9+/-3.9%), and in the plasma concentrations of free haemoglobin (93.1+/-37.8 vs. 57.8+/-24.3 g/dl), K+ (38.9+/-5.3 vs. 31.5+/-4.3 mm) and ATP (2.7+/-0.2 vs. 1.6+/-0.4 micromol/g haemoglobin), with higher levels detected in RCC, no remarkable differences (P>0.05) were observed regarding haemolysis (0.23+/-0.07% vs. 0.31+/-0.13) and pH value (6.63+/-0.03 vs. 6.62+/-0.02) between RCC and LWB at the end of storage. Lack of leucodepletion manifested in significantly (P<0.05) higher rates of haemolysis (0.44+/-0.21%), free haemoglobin (89.6+/-43.5 g/dl) and lower pH values (6.56+/-0.04). During 42 days of LWB storage, sufficient amounts (% of the initial mean value) were observed with stable (factor XI, 97.5+/-15.0) and labile (factor V, 92.9+/-18.0; factor VIII, 69.2+/-17.1) clotting factors and inhibitors (antithrombin III 88.9+/-9.5), without any signs of activated coagulation.

CONCLUSIONS

Our data indicate that the quality of LWB is comparable to that of components during 42 days of storage. Thus, LWB could be an interesting option for using to facilitate and economize the blood supply, especially for surgical or trauma patients.

Effects of extended storage of whole blood before leucocyte depletion on coagulation factors in plasma

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the quality of leucocyte-depleted plasma produced from leucocyte-depleted whole blood, stored for different periods of times before filtration through polyurethane filters.

MATERIALS AND METHODS

Whole blood was collected, from 48 voluntary donors, into quadruple blood bag sets with integrated whole-blood filters, and stored at room temperature for 1, 2, 6, or 18 h before filtration. Five samples were taken: one directly from the donor; one immediately after collection; one before and one after filtration; and one from plasma units before freezing. All samples were analysed for the following parameters: prothrombin time; activated partial thromboplastin time; prothrombin fragments F1+2; fibrinogen; factors VIII, XI and XII; von Willebrand factor antigen; ristocetin cofactor activity; collagen-binding capacity; multimers; and complement C3a-desArg.

RESULTS

Different whole-blood storage times before filtration did not have a significant effect on the stability of coagulation factors. The activity of all investigated coagulation factors in plasma was generally above 90 U/dl, even after 18 h of storage of whole blood before filtration. von Willebrand factor multimeric distribution remained stable throughout the process. However, activation of complement did occur during storage.

CONCLUSIONS

Leucodepleted plasma originating from leucodepleted whole blood maintains a satisfactory level of coagulation factors, even after the storage of whole blood for 18 h at room temperature before filtration.

The effect of leucocyte depletion on the quality of fresh-frozen plasma

The aim of this study was to evaluate the quality of leucodepleted (LD) fresh-frozen plasma (FFP) produced using one of five whole blood filters (Baxter RS2000 & RZ2000, NPBI T2926, Macopharma LST1 and Terumo WBSP) or two plasma filters (Pall LPS1 and Baxter FGR7014). Whole blood or plasma was filtered within 8 h of collection at an ambient temperature. Samples were taken pre- and post filtration for analysis of coagulation factors and complement activation (n = 7--12 for each type of filter). All filtered units (209--286 ml) contained < 5 x 10(6) residual leucocytes and < 30 x 10(9)/l platelets. Statistically significant losses of factors V, VIII, IX, XI and XII and increases in markers of coagulation activation were observed (0--21%), which were dependent on filter type. None of the filters had a significant effect on von Willebrand factor (VWF) multimeric distribution or the activity of VWF and factors II, VII or X. The effect on levels of C3a appeared to be related to the filter surface charge: positively charged filters resulted in C3a generation, whereas negatively charged resulted in C3a removal. None of the observed changes are likely to be clinically significant unless subsequent processing of plasma (such as pathogen inactivation) results in further losses of coagulation factors.