Introduction: Mesenchymal stem cells (MSCs) are being applied in clinical trials of various conditions. Overall, MSC has been considered safe when its safety was evaluated based on MSC therapy research articles published thus far. It is difficult, however, to confirm from the published papers if it is considered safe due to not reporting adverse events (AEs) or systematically monitoring of them. Without any protocols for a long-term follow up planned beforehand, evaluating MSC safety based just on previously published studies may be inappropriate. Therefore we conducted a systematic review of clinical trials that examined the use MSCs to evaluate their safety.

Methods: MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched from inception to October 2016. The primary outcome long-term adverse events (AEs) were counted from the all published article including case reports. Compared to control, how many were AEs observed in MSC treatment group. Methodological qualities of Safety outcome reporting were evaluated using questions from the McHarm quality assessment scale for AEs. Outcome data were analysed by using R, and presented as the pooled incidence rates of AEs or Odds ratios and 95% confidence intervals.

Results: Of 299 studies, 6 studies were reported tumour occurrence including benign mass, calcification, and ectopic tissues after MSC treatment. Of 299, 136 were controlled studies. Compared to control, MSC treatment more occur infection (OR=2.02, 95%CI: 1.61 to 2.53). Over 50% studies neither reported nor mentioned whether AEs occurred or not. Based on the Mcharm assessment, the majority of the studies did not report AEs appropriately.

Conclusion: Based on the current systematic review, MSC therapy appears to be safe. However, further MSC of safety must be explored through clinical studies based on the research design that allows for not only systematically monitoring its safety but also reporting whether it occurs or not to establish the appropriate safety profile of MSCs.

This research was supported by a grant (10172MFDS993) from Ministry of Food & Drug Safety in 2014