The concept of marrow-derived mesenchymal progenitor cells is nothing new and has already been proposed by a German pathologist Cohnheim in 1867.By observing analine dye-stained fibroblast-like cells during wound healing, Cohnhem hypothesized the existence of mesenchymal progenitor cells residing in the marrow that may participate wound healing.In the early twentieth century, numerous researchers claimed that they could recover fibroblasts in buffy coat culture.Polyblast was proposed by Maximow as the name forthese pluripotent circulating mononuclear cells.