•Mesenchymal stromal cells influence the cells of the immune system.
This influence is mainly due to the release of paracrine factors.
Extracellular vesicles are emerging as new tool for cell-to-cell
Mesenchymal stromal cells (MSCs) inhibit natural killer cell proliferation and
activity, suppress T lymphocyte proliferation, dendritic cells maturation and B
lymphocyte proliferation and activation. Moreover, MSCs may induce regulatory T
cells. Several factors released from MSCs have been implicated in their immune-
modulatory properties. These include soluble factors such as interleukins 6 and 10,
prostaglandin E2, hepatocyte growth factor, indoleamine 2,3-dioxygenase, nitric
oxide, transforming growth factor ß1, human leukocyte antigen and extracellular
vesicles. These vesicles released from cells have been characterized as a new
mechanism of cell-to-cell communication and emerged as mediators of the MSC-
immune-modulatory effects. In this review we focused our attention on the
extracellular vesicles as paracrine mediators of MC immune-modulation.