Freezing of Apheresis Platelet Concentrates in 6% Dimethyl Sulfoxide: The First Preliminary Study in Turkey.
OBJECTIVE
Transfusion of platelet suspensions is an essential part of patient care for certain clinical indications. In this pioneering study in Turkey, we aimed to assess the in vitro hemostatic functions of platelets after cryopreservation.


METHODS
Seven units of platelet concentrates were obtained by apheresis. Each apheresis platelet concentrate (APC) was divided into 2 equal volumes and frozen with 6% dimethyl sulfoxide (DMSO). The 14 frozen units of APCs were kept at -80 °C for 1 day. APCs were thawed at 37 °C and diluted either with autologous plasma or 0.9% NaCl. The volume and residual numbers of leukocytes and platelets were tested in both before-freezing and post-thawing periods. Aggregation and thrombin generation tests were used to analyze the in vitro hemostatic functions of platelets. Flow-cytometric analysis was used to assess the presence of frozen treated platelets and their viability.


RESULTS
The residual number of leukocytes in both dilution groups was <1x106. The mean platelet recovery rate in the plasma-diluted group (88.1±9.5%) was higher than that in the 0.9% NaCl-diluted group (63±10%). These results were compatible with the European Directorate for the Quality of Medicines quality criteria. Expectedly, there was no aggregation response to platelet aggregation test. The mean thrombin generation potential of post-thaw APCs was higher in the plasma-diluted group (2411 nmol/L per minute) when compared to both the 0.9% NaCl-diluted group (1913 nmol/L per minute) and the before-freezing period (1681 nmol/L per minute). The flow-cytometric analysis results for the viability of APCs after cryopreservation were 94.9% and 96.6% in the plasma and 0.9% NaCl groups, respectively.


CONCLUSIONS
Cryopreservation of platelets with 6% DMSO and storage at -80 °C increases their shelf life from 7 days to 2 years. Besides the increase in hemostatic functions of platelets, the cryopreservation process also does not affect their viability rates.
Gülhane Military Medical Academy, Blood Training Center and Blood Bank, Ankara, Turkey. Phone : +90 312 304 49 02 E-mail : soyilmaz@gata.edu.tr.
Soner
S
Yılmaz
Rıza Aytaç
RA
Çetinkaya
İbrahim
İ
Eker
Aytekin
A
Ünlü
Metin
M
Uyanık
Serkan
S
Tapan
Ahmet
A
Pekoğlu
Aysel
A
Pekel
Birgül
B
Erkmen
Uğur
U
Muşabak
Sebahattin
S
Yılmaz
İsmail Yaşar
İY
Avcı
Ferit
F
Avcu
Emin
E
Kürekçi
Can Polat
CP
Eyigün
D000328:Adult; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D001793:Blood Preservation / Q000379:methods*; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D007958:Leukocyte Count; D009994:Osmolar Concentration; D010865:Pilot Projects; D010974:Platelet Aggregation; D010976:Platelet Count; D017713:Platelet Transfusion; D010983:Plateletpheresis; D013917:Thrombin / Q000096:biosynthesis; D014421:Turkey
D003451:Cryoprotective Agents; D013917:Thrombin; D004121:Dimethyl Sulfoxide