Platelet activation during plasma-reduced multicomponent PLT collection: a comparison between COBE Trima and Spectra LRS turbo cell separators.

Background: The wide diffusion of multicomponent collection in donor apheresis has led to the yielding of different components, such as plasma-reduced platelet-pheresis at high PLT concentration. We investigated whether this collection modality could induce more PLT activation compared to standard plateletpheresis.
Study Design and Methods: Forty-one plateletpheresis collections (20 Trima and 21 Spectra LRS Turbo v.7.0, COBE) were evaluated. Donor, procedure, and product data were recorded. ADP, collagen, and U46619 (a thromboxane-A2 analog)-induced PLT aggregation was investigated in basal (donor) and final (plateletpheresis unit) samples. The expression of PLT activation marker P-selectin (CD62P) was studied using flow cytometry in basal and final samples. In all cases, P-selectin was investigated in final samples after stimulation with ADP to assess for a possible further release of the antigen. Four additional plateletpheresis procedures were performed in donors from Group A, using the traditional, nonplasma-reduced program.
Results: Plateletpheresis obtained by means of the Trima device showed a lower response to in-vitro induced PLT aggregation and a higher percentage of P-selectin-expressing PLT when compared to products obtained using the Spectra device. Moreover, P-selectin release after ADP stimulation was reduced in plateletpheresis units obtained using the Trima device. These differences disappeared when a nonplasma-reduced collection program was used. In-vivo evaluation did not detect any difference between plateletpheresis obtained by means of the two cell separators.
Conclusions: Plateletpheresis units obtained by means of multicomponent collection show a higher degree of PLT activation compared to traditional plateletpheresis procedures when high-concentration plasma-reduced products are collected. Randomized clinical studies are needed to assess the real impact of these findings in terms of in-vivo efficacy of plasma-reduced plateletpheresis units.