Sanne de Bruin

190 Chapter 7 Discussion Here, we describe a reproducible protocol for biotin-labeling of PCs under GPG condi- tions in a closed system. Showing a lowwithin and unit to unit variation. The findings will be of interest to blood banks and clinical researchers. BioPLTs can be used to evaluate the in vivo effect of new additive solutions, donor variability and the effect of transfusion in various patient categories. The major advantage of biotin is that it enables in vivo tracing of transfused platelets without exposing the recipient to radiation. Moreover, bioPLTs enable tracing of multiple populations concurrently. Also, bioPLTs can be isolated from venous blood samples, thereby permitting direct population analysis for surface markers and metabolomics composition of the platelet subgroups. HLA discrepancy is another non-radioactive method to discriminate transfused platelets from the patients’ circulating platelets. 18 However, this method inherently requires a HLA discrepancy, which excludes the pos- sibility of tracing HLA-matched platelet transfusions or autologous transfusions in the recipient. Also, isolation and subanalyses of platelets are not possible with this method. Figure 6. Stability of biotin label and CD62P expression of stored bioPLT. BioPLTs were returned to the retained fraction of the original PC, to enhance storage conditions. (n=3). A The percentage of biotinylated platelets remained stable througout 7 days of storage. (mean of 12.6% at day 1 and 13.0% at day 7). B. CD62P expression was assessed in unstimulated platelets (red), after stimulation with ADP (blue) and TRAP (green). CD62P expression was determined in both labelled (dotted lines) and unlabelled cells (continuous line). Measurements were performed at day 1,4,5,6 and 7. N=3