In vitro affinity reduction of biologic response modifiers from production buffy coat platelets exposed to recombinant protein receptors

Cryopreservation of buffy coat-derived platelet concentrates photochemically treated with amotosalen and UVA light

BACKGROUND

Cryopreserved platelets (CPPs) are considered a promising approach for extended platelet storage, bridging inventory shortages of conventionally stored platelets. It is unknown if platelet concentrates exposed to photochemical treatment (PCT) with amotosalen and ultraviolet A (UVA) light, to inactivate pathogens, are suitable for freezing. The objective of this study was to analyze potential effects of PCT on CPPs as compared with untreated CPPs.

STUDY DESIGN AND METHODS

A total of 12 PCT-treated and 12 untreated platelet units from buffy coats were cryopreserved at -80°C in 5% dimethyl sulfoxide. CPPs of both types were rapidly thawed at 37°C and resuspended in 200 mL fresh plasma. In vitro properties were analyzed prefreezing, postfreezing and thawing, and on Day 1 after thawing.

RESULTS

Directly after thawing, no major differences in platelet content, lactase hydrogenase, adenosine triphosphate, mitochondrial membrane potential, CD62P, CD42b, and platelet endothelial cell adhesion molecule were seen between PCT-CPPs and conventional CPPs. Agonist-induced PAC-1 expression and contribution of CPPs to blood coagulation in an experimental rotational thromboelastometry setup were also similar between the groups. On Day 1 after thawing, the CPPs of both types performed less well. The PCT-CPPs tended to be more affected by the freezing process than the conventional CPPs.

CONCLUSIONS

PCT-CPPs appeared slightly more susceptible to lesion effects by freezing than conventional CPPs, in particular in assays on Day 1 after thawing, but these differences were small relative to the dramatic effects of the freezing process itself.

Optimized processing for pathogen inactivation of double-dose buffy-coat platelet concentrates: maintained in vitro quality over 7-day storage

BACKGROUND AND OBJECTIVE

Efficient pathogen inactivation (PI) offers the possibility of increasing the number of buffy coats per pool without the concurrent increased risk of pathogen transmission. Here, we describe the findings of in vitro analyses of platelets from pools of eight buffy coats treated with amotosalen and UVA light (INTERCEPT Blood System for Platelets) using INTERCEPT disposable processing sets with plastic materials sourced from alternate suppliers and split afterwards to obtain two therapeutic transfusion doses.

METHODS

Double-dose platelet concentrates were prepared from pools of eight buffy coats in additive solution (SSP+) using either previous 6-lead or new 8-lead pooling sets and PI processing sets in previous or alternate supplier sourced plastics (AS). Platelets were treated with the INTERCEPT Blood System then stored for up to 7 days and tested for in vitro quality.

RESULTS

All tested units (n = 30) were in conformity with European guidelines. Using AS sets more effectively maintained glucose reserves (P < 0·01), reduced lactate production (P < 0·01), reduced CD62P expression (P < 0·01) and downregulated levels of surface CD42b (P < 0·01) overtime. AS set maintained JC-positive cells (NS) between day 2 and day 7 and sustained platelet integrin activation (PAC-1) between day 2 and day 7 (NS). Overall sCD40L and PGDF accumulated in an equivalent way (P < 0·01) within series.

SUMMARY/CONCLUSIONS

In summary, our data demonstrate that PI treatment using AS sets, in combination with the new pooling set for double-dose platelet preparation, maintained the platelet in vitro quality over 7 days of storage.

Duration of red blood cell storage and inflammatory marker generation

Red blood cell (RBC) transfusion is a life-saving treatment for several pathologies. RBCs for transfusion are stored refrigerated in a preservative solution, which extends their shelf-life for up to 42 days. During storage, the RBCs endure abundant physicochemical changes, named RBC storage lesions, which affect the overall quality standard, the functional integrity and in vivo survival of the transfused RBCs. Some of the changes occurring in the early stages of the storage period (for approximately two weeks) are reversible but become irreversible later on as the storage is extended. In this review, we aim to decipher the duration of RBC storage and inflammatory marker generation. This phenomenon is included as one of the causes of transfusion-related immunomodulation (TRIM), an emerging concept developed to potentially elucidate numerous clinical observations that suggest that RBC transfusion is associated with increased inflammatory events or effects with clinical consequence.