Table 2.
Characterization of GMP-Expanded Tregs before and after Cryopreservation
| Test | Recipient Blood |
Healthy Control |
ESKD1 |
ESKD2 |
|||
|---|---|---|---|---|---|---|---|
| specification | final harvest | defrosting | final harvest | defrosting | final harvest | defrosting | |
| Identity | positive for CD4, CD25, and FOXP3 | yes | yes | yes | yes | yes | yes |
| Purity | ≥60% of entire cell population CD4+CD25+FOXP3+ | 88.2 | 71.7 | 74.7 | 70.5 | 76.7 | 88.6 |
| Impurity | ≤10% CD8+ | 0.41 | 4.68 | 1.82 | 9.61 | 1.6 | 6.35 |
| Viability | ≥70% viability | 96.5 | 76 | 96 | 93 | 95 | 82 |
| Potency | ≥60% suppression | 81 | 97 | 83.1 | 84 | 91.3 | 95 |
Characterization of the expanded Tregs was performed to ensure the final product satisfied the specified release criteria in order to allow their future clinical application. Release criteria: (1) positive for CD4+CD25+FOXP3+; (2) CD4+CD25+FOXP3+ cells ≥60% of live cells; (3) CD8+ cells ≤10%; (4) viability ≥70%; and (5) suppression ≥60%. The two ESKD patients and the healthy control met the specified release criteria before and after 12 weeks of cryopreservation in vapor phase liquid nitrogen.