Table 3

Release criteria and stem cell quality control

CriteriaTesting methodReleased criteria
Positive markers (%) (median, range)
CD73Flow cytometry using the Human MSC Analysis Kit (Becton Dickinson,USA)>95%
Negative markers (%)<2%
Cell viability (%) (mean±SD)Trypan blue staining>80%
Microorganism testsBacT/Alert 3D microbial detection system (Biomerieux, USA)Negative
MycoplasmaMycoAlertTM plus mycoplasma detection kit (Lonza, Switzerland)Negative
EndotoxinEndosafe-PTS (Charles river laboratories)≤5 EU/kg
Immunoregulatory assayFlow cytometryNot 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.