White cell apoptosis in platelet concentrates.
BACKGROUND
The aim of the present study was the evaluation of the apoptosis in residual white cells (WBCs) contained in platelet concentrates (PCs) and of the relationship of this apoptosis with the concentration of inflammatory cytokines in the medium and with platelet activation.


METHODS
Three independent methods were used to evaluated apoptosis in WBCs present in 9 PCs, either from single donors by apheresis (SD-PCs) or from pooled buffy coats (BC-PCs). All PCs were divided in two parts, one of which was irradiated. PCs were stored up to 4 days at room temperature, and samples were withdrawn daily for analysis of apoptosis, of platelet activation (surface and soluble CD62P), and of cytokine concentration (interleukin [IL]-1alpha, IL-1beta, IL-6, IL-8, and tumor necrosis factor alpha).


RESULTS
Apoptosis was found to occur with storage in both irradiated and nonirradiated units. Platelet activation increased with storage time and was higher in BC-PCs. The amount of released cytokines was rather variable among PC units. Only IL-8 was consistently found to increase with storage time.


CONCLUSIONS
Apoptosis of residual WBCs occurred in PC units as a function of storage time. The amount and the time course of apoptosis seem to correlate with IL-8 release rather than with platelet activation or with the occurrence of febrile nonhemolytic transfusion reactions.
Frabetti
F
F
Immunohematology and Transfusion Service, Policlinico S. Orsola, and the Institute for Histology and General Embryology, University of Bologna, Bologna, Italy.
Tazzari
P L
PL
Musiani
D
D
Bontadini
A
A
Matteini
C
C
Roseti
L
L
Tassi
C
C
Viggiani
M
M
Marini
M
M
Conte
R
R
D017209:Apoptosis; D001792:Blood Platelets / Q000166:cytology*; D002462:Cell Membrane; D004396:Coloring Agents; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007962:Leukocytes / Q000166:cytology*; D015539:Platelet Activation; D010983:Plateletpheresis
D004396:Coloring Agents; D016207:Cytokines