Annexin V binding during storage of platelet concentrate from buffy coat, after patogen reduction treatments

Abstract

Background:Pathogen reduction technology (PRT) is important for limiting transfusion transmitted infections. Intercept* treated platelet concentrates (PC) have been implemented in our centre since 2008, and other systems have been evaluated. Aim:To determine if PRT for PC increase cellular injury or apoptosis during storage, Annexin V was measured after three PRTs. Methods: Platelet concentrates from buffy coat (BC-PC) were obtained by pooling 5BC from standard whole blood donations, after PRT was applied. With Intercept* (amotosalen+UVA light) 12 BC-PC were studied, using Intersol as additive solution(AS). Thirteen BC-PC were evaluated using MirasolÒ(Riboflavin + UV light). TwelveBC-PC were evaluated using Teraflex* (UVC light). In both of these the AS used wasSSP plus. In all PRTs the ratio plasma: AS was approximately 35:65. All PCs were storedat 22°C until day 9 after donation. In vitro parameters tested on days 2, 5, 7 and 9 wereswirling, MPV, pH, CD62p, glucose, lactate and LDH. Annexin V binding was measuredby FC (labeled with FITC) to determine the cellular injury during storage. Correlationbetween values of Annexin V (in three PRTs) and other parameters, was performedusing Spearman test correlation. Results: Annexin V as an apoptotic marker was correlationated with other plateletmetabolic and functional parameters tested. The percentage of platelets binding ann-exin V tended to be lower in PCs treated with InterceptÒand Teraflex*. In general thecorrelation was weak with all parameters tested, but some tests showed good corre-lation (r‡0.60) like MVP, CD62p, glucose, LDH in different days of storage. When PCs were evaluated on day 7 of storage: (i) in Intercept* units no correlation was shown, (ii) in Mirasol* units good correlation (r‡0.71) was found with MVP and glucose (iii) inTeraflex* units, correlation (=0.50) was only detected with LDH. During storage, Annexin V binding of all units increased steadily. But Intercept* and Teraflex* PCsremained comparable to control units (previous study). Mirasol* PCs had higher valuesduring terminal storage. Platelet activation and apoptosis are evident from day 5 ofstorage but they show a degree of overlap as we can see. Swirling scores were goodthroughout the 7 days of storage. Residual leucocytes by FC were in all PC <1·106.Conclusion:The correlation between Annexin V binding and other parameters wasbetween weak and intermediate. Mirasol* units exhibited the highest values for Annexin V on day 7 of storage. During storage all units showed a steady increase in Annexin V although there were differences in PRTs and it could be due to specificprocess of PRTs and storage media. The question whether markers of platelets apoptosiswill be relevant for clinical efficacy should be determined in future studies.