(P-BB-17) Biochemical Parameters At Day 7 Of Storage Of Pathogen Reduced (UVA/Amotosalen) And Conventional Platelets In Additive Solution With Or Without Irradiation.

Background/Case Studies: Conventional apheresis platelets (PLTs) may be stored for up to 7 days when processed in FDA approved or cleared storage bags, while pathogen reduced (PR, UVA/amotosalen) PLTs are currently approved for 5-day storage in the US and up to 7 days in other countries. While PR is a potential alternative to irradiation to reduce the risk of transfusion associated graft versus host disease, irradiation continues to be performed by some transfusion facilities.

Study

Design/Methods: We compared in vitro parameters of PLTs and PR PLTs at 7 days. In addition, we evaluated the effect of gamma or X-Ray irradiation at 2500cGy on Day 1. Six healthy volunteers donated 2 units of double apheresis PLTs suspended in 65% PAS-3/35% plasma, each donation separated by >4 weeks. One donation was PR, the other not. We split each double unit in half and irradiated (Irr) one half before storage. Parameters measured were: PLT concentration, mean PLT volume (MPV), pH, glucose, pO2, pCO2, lactate, CD62P, CD63, CD36, CD29, GPVI, CD41a, CD42a, CD42b, annexin V binding, aggregation (TRAP), mitochondrial membrane potential (MMP), reactive oxygen species (ROS).

Results/Findings: At day 7, compared to non-PR PLTs, PR PLTs had significant decline in PLT content, pH, MMP, aggregation and significant increases in MPV, pO2, CD62P, Annexin V binding and ROS production. Several parameters were impacted by PR and/or irradiation (Table 1). PLT parameters were similar at Day 1, except MMP which was higher in Non-PR or Non-PR Irr compared to PR or PR Irr.
Table 1. Selective PLT parameters at day 7.

Conclusions: In comparison to PLTs at day 7, PR PLTs have significant changes in aerobic metabolism as indicated by loss of MMP, increased oxygen levels, ROS production, lower pH, and less glucose consumption. These changes likely contribute to increased level of activation, phosphatidylserine expression indicative of apoptosis, increased PLT volume and loss of PLTs by day 7, irradiation is associated with additional declines in PR PLT quality, though differences between irradiated and non-irradiated PR PLTs are lesser compared to PR and non-PR PLTs. This abstract reflects the views of the authors and should not be construed to represent FDA's views or policies.

Importance of research: In US, pathogen reduced (PR) platelets (PLTs) have a 5-day shelf life. Irradiation (Irr, gamma and X-ray) is an established method of preventing GVHD and some transfusion centers continue this practice with PR PLTs. Irr has been shown to not reduce quality of PLTs, but it is not clear if Irr could negatively impact 7-day PR PLTs. Our data indicate that by day 7 PR PLTs are more damaged than conventional PLTs. Irr appears to extend the processing and storage lesion in PR PLTs.