TABLE 2.

Effects of suboptimal storage temperature and temperature cycling on cell health during storage^a

Storage condition and cell health indicator	Avg no. of cells (%)b	Odds ratio	95% CI	P
Controlc
Viability	97.5
Apoptosis	7.1
Suboptimal storage tempd
Viability	63.2	23.0	18.5-28.7	<0.001
Apoptosis	55.8	0.06	12.5-39.9	<0.001
Storage temp cyclinge
Viability	76.5	12.2	9.8-15.1	<0.0001
Apoptosis	41.7	0.11	0.09-0.12	<0.0001

^aA 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.

^bBy definition, the number of detectable living cells indicates viability and the number of nonliving cells indicates apoptosis.

^cA total of 20 aliquots from each donor were maintained in LN₂ storage.

^dA 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.

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