WHO/BS/2019.2376 Collaborative Study to assess the suitability of the candidate WHO IRR for MSC identity (for flow cytometry) for advance therapies

Overview

We report the results of a collaborative study that was conducted with the aim to asses a reference reagent for mesenchymal stem cell identity for flow cytometry. Currently, there are no standards available for mesenchymal stem cells. 75 vials were produced. The vials are stable for 6 months at -20 degrees. 15 participants from 9 different laboratories took part. The collaborators were asked to run the reagent in their inhouse flow cytometry set-up as usual, and report back as if it was one of their own samples. No restrictions or recommendations were given.

The collaborative study showed that the reference reagent performed extremely well under all the different conditions. The mean values from this study fall very close to the ranges for % expression for each of the markers in the ISCT recommendations for MSC identity, and it was possible to generate a range for each marker that was +/- 2SD. The reagent is not a replacement for the ISCT values but a tool to help researchers to validate their equipment and results. In addition, this pilot study allowed us to identify issues around the development and establishment of novel reference reagents for advanced therapies.