We read with interest the article by Peng et al. investigating the potential beneficial effects of culture expanded autologous mesenchymal stem cells (MSCs) in patients with liver failure caused by hepatitis B virus (HBV).1 Though it is reassuring that MSC therapy delivered via the hepatic artery in this group of patients appears to be safe and feasible, there are several areas of the article that would benefit from clarification.
It would be helpful if the investigators could provide data regarding HBV viral load, genotype, and E antigen status for each patient in the trial, as they are important risk factors for progressive liver disease and hepatocellular carcinoma.2, 3 These data, in addition to hepatitis C virus coinfection, are required before robust conclusions about the efficacy of MSC therapy can be made.
Patients on antiviral treatment were excluded from the trial. We would like the investigators to clarify whether HBV antiviral therapy was given at any time to the enrolled patients. This is of importance, because the efficacy of antiviral therapy in this patient group has been well established for over a decade.4, 5 In contrast, the antiviral, antifibrotic, and regenerative effects of MSCs have not been proven.6
Furthermore, the surface expression of cluster of differentiation (CD)73, CD90, CD105, and evidence of trilineage differentiation, which are required to define a pure MSC population, have not been provided.7 The article would benefit from inclusion of such data, because culture-expanded MSCs are frequently heterogeneous and can contain contaminating cells.8
In summary, we feel additional data are required before firm conclusions about the efficacy of MSC therapy in HBV liver failure can be made. Moreover, MSC therapy should only be considered after an optimization of antiviral therapy in future clinical trials.