Storage induced apoptosis of peripheral blood mononuclear cells obtained from leucoreduction system chambers

Abstract

Recently, it was reported that leucocytes obtained from leucoreduction system chambers (LRSCs) after plateletapheresis show excellent quality due to culture of dendritic cells. This study analysed apoptosis of mononuclear cells derived from LRSCs of single platelet units (SPUs) and double platelet units (DPUs) during storage. This randomized prospective study compared eighteen single and double platelet units produced with the Trima Accel cell separator. Buffy coat was drained from the LRSCs and analysed after 1, 6, 24, 48 and 72 h. CD45+ lymphocytes and CD14+ monocytes cells as well as Annexin-V+ and 7-AAD+ mononuclear cells were measured by flow cytometry. The WBC concentration of LRSCs obtained from SPUs and DPUs differed significantly (SPUs: 0·93 ± 0·32 ×10(5) per μl WBCs; DPUs: 1·71 ± 0·55 ×10(5) per μl WBCs; P<0·001). Processed blood volume (PBV) correlated significantly with WBC concentration (r(2)=0·75, P<0·001). Fifty percent of monocytes were Annexin-V-positive 1 h after production decreasing to 30% during 24 h of storage. Compared to that, the part of late apoptotic or necrotic PBMCs increased later on, after 24 h. After 24 h, Annexin-V- and 7-AAD-positive, late apoptotic and necrotic lymphocytes and monocytes doubled. PBMCs stored in autologous plasma in PVC-bags at room temperature did not show an increase of 7-AAD-positive PBMCs during 24 h prior to cell processing but increased significantly thereafter.