The Immunomodulatory Potential of Mesenchymal Stromal Cells: A Story of a Regulatory Network.

Mesenchymal stromal cells (MSCs) have recently been the subject of great interest in the fields of regenerative medicine and immunotherapy due to their unique biological properties. In particular, MSCs possess immunoregulatory properties that can modulate immune as well as inflammatory responses. Although there are many studies about MSC immunomodulation, several complex and conflicting mechanisms have been reported. Herein, we aim to review these mechanisms and identify a link between these pathways. We focus on human studies in which bone marrow-derived MSCs and T cells were investigated. We propose that MSC-induced immunomodulation exists as a network where converging regulatory pathways compete to establish a tolerogenic state. As interleukin-10 seems to play a central role in this network, we also discuss the relationship between this cytokine and other regulatory factors in the context of immunomodulation.