Abstract

Continuous emergence of known or new pathogens as well as increasing complexity of pathogen testing challenge the provision of safe blood products. Pathogen inactivation using amotosalen + UVA effectively reduces a number of different pathogens including viruses, bacteria and parasites (

Transfusion
2006
;
46
:
1168
).

We determined the impact of pathogen inactivation on the coagulation activity of frozen plasma (FP) using amotosalen (150μM) and UVA (3 J/cm2) in the operational setting of a large blood bank. Plasma (650mL) was collected as single-donor apheresis plasma processed within 8h (arm A) and whole blood derived plasma pooled from three different, but ABO and Rh identical donors after an initial storage time of 8h (arm B) or after 22h (arm C) before photochemical treatment (PCT). Each 650mL unit of treated plasma was divided into 3 units of 200mL each prior to freezing at −40°C. Eight subsequent FP units (200mL) from individual collections were analyzed per arm, representing different blood groups. Samples for coagulation analysis were taken at baseline, after PCT and absorption of amotosalen (post-inactivation), and after six weeks of storage at −40°C (post-storage). Global coagulation tests (PT, aPTT), thrombin time, fibrinogen activity (Clauss) and fibrinogen antigen levels remained within normal ranges at all time points in all three arms. Similarly, activities of coagulation factors II, V, VII, IX, X, XI, XII, XIII, as well as von Willebrand factor (vWF) antigen, ristocetin cofactor, vWF-collagen binding capacity, antithrombin, protein C levels, protein S activity, plasmin-antiplasmin-complexes (PAP), plasminogen levels, and D-dimers did not show significant alterations. Median factor VIII activities were diminished compared to baseline (= 100%) in all three groups post-inactivation and post-storage, respectively (A: 84% and 80%; B: 74% and 65%; C: 84% and 93%). Significant differences in thrombin-antithrombin-complex (TAT) levels were seen between apheresis plasma (< 0.1 ng/ml) and plasma processed from whole blood after 8h (7.25 ng/ml) and 22h (57 ng/ml) of storage time prior to PCT. During pathogen inactivation, there was no increase in TAT levels ruling out that thrombin was formed through the inactivation process.

In summary, pathogen inactivation of FP using amotosalen + UVA does not significantly influence coagulation parameters with the exception of FVIII. The decrease in FVIII activity might be explained in part by an additional freeze-thawing cycle included in the protocol due to technical reasons. Increased TAT levels, especially in arm C, were not reflected in decreased AT activity or an increase in other markers of coagulation activation, but indicate continuous, although moderate activation of the coagulation cascade during storage time.

We conclude that the described inactivation procedure for whole blood derived and apheresis FP can be performed in a large blood bank setting without significant decreases in coagulation factor activities and thus without major impairment of the functional capacity of therapeutic plasma.

Disclosures: Margaret Rheinschmidt (Cerus); Laurence Corash (Cerus).; Margaret Rheinschmidt (Cerus); Laurence Corash (Cerus).; Research funding by Cerus Corporation for the study presented (Markus M. Mueller & Reinhard Henschler).; Laurence Corash (Cerus).

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