The suppressive effect of mesenchymal stromal cells on T cell proliferation is conserved in old age

Mesenchymal stromal cells (MSC) have become a useful tool in curing graft versus host disease (GVHD) after transplantation. No information is presently available whether the immunosuppressive properties of this cell type are maintained in old age. It was therefore the aim of our study to analyze the immunoregulatory effect of MSC on peripheral blood mononuclear cells (PBMC) in old age. We studied the proliferation, activation and cytokine production of PBMC following co-culture with MSC from young (<30 years) and old (>61 years) donors. Our results demonstrate that MSC from elderly donors exhibit the same suppressive effects on T cell proliferation as their young counterparts. In both age groups T cell activation was not influenced by co-culture with MSC from young and elderly donors. With the exception of IL-6, cytokine production by unstimulated or stimulated PBMC was also not affected by MSC from either age group. IL-6 production was increased during co-culture of PBMC and MSC and was higher when MSC from elderly donors were used. After PHA stimulation, however, this age-specific difference was balanced and appeared even. As high IL-6 production is a prerequisite for an effective suppression of T cell proliferation, MSC can be considered a powerful tool for immunoregulatory therapies in old age.