In vitro cell quality of buffy coat platelets in additive solution treated with pathogen reduction technology

Pathogen reduction technologies (PRTs) may induce storage lesion in platelet (PLT) concentrates. To investigate this, buffy coat PLTs (BCPs) in PLT additive solution (AS; SSP+) with or without Mirasol PRT (CaridianBCT Biotechnologies) were assessed by quality control tests and four-color flow cytometry.

In vitro comparison of PRT and control pooled-and-split BCPs after 2, 3, 6, 7, and 8 days of storage was made. PLT concentration, count per unit, swirl, metabolism, activation (CD62P, PAC1, CD42b/GPIb, CD63, CD40L/CD154, CD40, annexin V), and microparticle, sCD40L, and sCD62P release were evaluated.

PRT induced a minor initial PLT loss (Day 2 [mean±SD], 302×10(9) ±44×10(9) PLTs/unit vs. 325× 10(9) ±46×10(9) PLTs/unit; p<0.001) but the decline was comparable to control BCP. Swirling was comparable and declined with similar rates in PRT-treated and control BCPs during storage. PRT enhanced PLT metabolism and activation, evidenced by lower pH(22) ; increased glucose consumption and lactate production rates (p<0.01); early increases in CD62P-, PAC1-, CD63-, CD40L-, CD40-, and annexin V-positive PLTs; reduced GPIb expression; and enhanced release of PLT-derived MPs and sCD40L (all p<0.05). CD62P and PAC1 expression changed with different kinetics during storage and varying GPIb expression was displayed within the CD62P/PAC1-positive PLT subsets.

PRT treatment of BCP in AS induced a minor initial PLT loss and enhanced metabolism and PLT activation. The clinical relevance for PLT function in vivo of these findings will be investigated in a clinical trial.