In-vitro quality of platelet concentrates, x-ray-irradiated, at the beginning or end of storage

Background

X-ray-irradiation of blood product is used to inactivate lymphocytes to prevent TA-GvHD, similar to γ-irradiation. Compared with γ-irradiation, X-ray-irradiation is preferable from an operational point of view, as the radiation emission is easier to control and thus safer. Only limited data is available from literature on the quality of x-ray-irradiated platelet concentrates (PC), which we evaluate here In-vitro, compared to untreated controls, dependent on the storage time before treatment.

Methods

Plasma-reduced PC in SSP+ were derived from pools of 4 buffy coats after overnight storage of whole blood. PC were used in two sets of experiments (n=6 each). In a pool and split design, two PC were merged and separated, with one bag remaining untreated, while the other was x-ray-irradiated at 25 to 50 Gy using an X-ray blood irradiator RADGIL2 (Gilardoni, Italy). Bags were irradiated either directly after PC production on day 2 (set 1) or on day 5 (set 2) at the end of storage. PC were stored under agitation at 22 ± 2°C and sampling to determine platelet quality was done on day 6. The quality parameters observed for this study were PLT number, pH, presence of swirling, collagen-induced aggregation, CD62P exposition and Annexin V binding.

Results

PCs were in accordance with the German guidelines with respect to platelet content (>2 x 10¹¹/unit)) and pH (pH between 6.4 to 7.8). When comparing untreated controls with the corresponding X-ray-irradiated PCs no significant differences were detected for collagen-induced aggregation (table). Annexin V binding and CD62P exposition were slightly but significantly elevated in the x-irradiated bags. There was no significant difference in the quality of PCs x-ray-irradiated directly after production compared with those x-ray-irradiated at the end of storage (unpaired t-test, p < 0.05).

Conclusion

Platelet quality is well preserved after x-ray radiation with only minor differences in platelet activation (CD62P and Annexin V) between X-radiated PCs and the corresponding untreated controls at the end of storage. The time point of irradiation, immediately after production or at the end of shelf life, had no effect on the platelet quality parameters we examined in this study.

Offenlegung Interessenkonflikt:

No conflict of interests