TABLE 2.

Effects of suboptimal storage temperature and temperature cycling on cell health during storagea

Storage condition and cell health indicatorAvg no. of cells (%)bOdds ratio95% CIP
Controlc
    Viability97.5
    Apoptosis7.1
Suboptimal storage tempd
    Viability63.223.018.5-28.7<0.001
    Apoptosis55.80.0612.5-39.9<0.001
Storage temp cyclinge
    Viability76.512.29.8-15.1<0.0001
    Apoptosis41.70.110.09-0.12<0.0001
  • a A total of 100 frozen aliquots of PBMC from each of two donors (M3143 and M5020) were tested. Results were combined across both donor PBMC samples. The analysis for individual donors was consistent with the pooled analysis. One assay run testing aliquots for donor M3143 was lost; so, for this donor, the results for analysis were reduced to 15 aliquots for the control and 34 aliquots each for suboptimal storage temperature and temperature cycling during storage.

  • b By definition, the number of detectable living cells indicates viability and the number of nonliving cells indicates apoptosis.

  • c A total of 20 aliquots from each donor were maintained in LN2 storage.

  • d A total of 40 aliquots from each donor were subjected to an 8-h period of storage at −20°C and then returned to LN2 storage.

  • e A total of 40 aliquots from each donor were subjected to three cycles of storage change between LN2 to −70°C and back to LN2.