Release criteria and stem cell quality control
| Criteria | Testing method | Released criteria |
| Positive markers (%) (median, range) | ||
| CD73 | Flow cytometry using the Human MSC Analysis Kit (Becton Dickinson,USA) | >95% |
| CD90 | >95% | |
| CD105 | >95% | |
| Negative markers (%) | <2% | |
| Cell viability (%) (mean±SD) | Trypan blue staining | >80% |
| Microorganism tests | BacT/Alert 3D microbial detection system (Biomerieux, USA) | Negative |
| Mycoplasma | MycoAlertTM plus mycoplasma detection kit (Lonza, Switzerland) | Negative |
| Endotoxin | Endosafe-PTS (Charles river laboratories) | ≤5 EU/kg |
| Immunoregulatory assay | Flow cytometry | Not Applicable |
To assess the quality of UC-MSCs for administration, a set of release criteria was defined, which included the following: the positive markers (CD73, CD90 and CD105) must be higher than 95%, the negative markers (CD11b, CD19, CD34, CD45 and HLA-DR) must be less than 2%; the cell viability must be higher than 80% with a normal karyotype; and the cell product must be free from microorganism infections and mycoplasma. Immunoregulatory assays will be performed to assess but not consider released criteria.
HLA-DR, Human Leukocyte Antigen - DR isotype; UC-MSC, umbilical cord-derived mesenchymal stem/stromal cells.