Cytokine technology in basic and applied research on the hematopoietic system

Comparison of cytokine levels and metabolic parameters of stored platelet concentrates of the Fundação Hemominas, Belo Horizonte, Brazil

Background

Prolonged storage of platelets could improve availability and logistical management and decrease wastage. Immunobiochemical methods can be used to guarantee the quality of platelets after prolonged storage.

Objective

The aim of this study was to compare storage-related changes in buffy coat-derived platelet concentrations versus platelet-rich plasmal.

Methods

Units of whole blood were drawn using a quadruple-bag blood container system. Platelet-rich plasma and buffy coat prepared from whole blood following standard methods were stored for 9 days. During this period test samples were aseptically collected for analysis on Days 1, 2, 3, 5, 7 and 9.

Results

The highest CD42b expression was greater than 95%. The percentage of CD62p was significantly lower than the CD42b expression. The pH remained fairly stable during storage. Measurement of pO₂ and pCO₂ showed that oxygen levels were significantly higher than carbon dioxide levels. There were no significant differences in bicarbonate levels, glucose consumption and lactate production between the groups. The swirling effect with platelet-rich plasma samples decreased after 5 days of storage and after 7 days of storage for buffy coat samples. There was a significant twenty-fold increase in the mean IL-1β after 5 days of storage for both groups. Slight increases in IL-6 and IL-8 levels were seen at 5 days.

Conclusion

The quality of platelet concentrates remained acceptable during 7 days of storage in respect to the swirling effect, pH and platelet activation. There were no significant differences between buffy coat-derived platelets and platelet-rich plasma in this study.

The role of cytokines in blood transfusion reactions

Recent advance in the understanding of the mechanism of hemolytic transfusion reactions results from the investigation of cytokine generation in in vitro models of incompatible red blood cell transfusion. Cytokines with pyrogenic and pro-inflammatory activities as well as cytokines with activating properties for granulocytes, monocytes and endothelial cells are produced in both 'intravascular' and 'extravascular' types of hemolytic reactions. It has also been demonstrated that cytokines are generated and accumulated in blood components such as platelet concentrates, during storage. A large part of febrile transfusion reactions results from transfusion of stored platelet concentrates containing high cytokine levels and not from antigen-antibody reactions. Prestorage removal of white blood cells, which generate cytokines during storage, from platelet concentrates reduces strongly the reaction incidence and should be standard practice.