Human platelets frozen with glycerol in liquid nitrogen: biological and clinical aspects

Abstract

Platelets were frozen using glycerol (3% in plasma) as a cryoprotective agent, a rapid cooling rate, and liquid nitrogen for storage. The cryopreserved platelets were thawed at 42 C and infused without washing. The results indicate that the quality of the thawed platelets is equivalent to platelets stored for 24 to 48 hours at room temperature. The availability of HLA phenotyped leukocyte poor platelets can reduce the frequency of sensitization to strong antigens and provide clinically effective platelets for alloimmunized patients.

REVISITATIONOFTHECLINICALINDICATIONSFORTHETRANSFUSIONOFPLATELETCONCENTRATES

“…Notwithstanding the hopes and great scientific effort so far, the technology of platelet freezing has produced disappointing results. The majority of protocols require deep freeze storage capability and involve the use of dimethyl sulfoxide as a cryoprotectant (56–58), although glycerol, glucose and other reagents have also been used (59–61). In more recent years, a novel approach to platelet freezing has been developed by including a number of chemicals able to reduce platelet activation and the significant damages produced in vital components of the platelet structure by the thermal transitions occuring during freezing and thawing in the solutions used in the cryopreservation process (62).…”

Improved Procedure for Platelet Freezing

“…Several modifi cations have been attempted to improve or simplify the technique with satisfactory in vitro results and clinical trials [6][7][8][9][10][11]. However, some investigators have obtained poor results and judged the glycerol methods to be gen erally inferior to techniques using DMSO as the cryoprotectant [12][13][14][15][16][17], We report here a standardized technique which incor porates important recent modifications of the glycerolglucose method to overcome some of the problems encountered earlier [3,5], Acidified plasma had been used together with other measures to reduce the frequency of post-thaw clumping, but the survival of such frozen plate let concentrates (PC) was often less than optimal.…”