The present invention relates to the use of at least one isolated multipotent stem cell for maintaining haematopoiesis in vitro, in which said multipotent stem cell is preferably a mesenchymal stem cell or, more preferably, said mesenchymal stem cell is a mesenchymal stem cell capable of expressing the nestin protein. The present invention also relates to an isolated cell population of adult nestin-positive mesenchymal cells from a mammal, including humans, to the use thereof for producing a drug for maintaining haematopoiesis in a mammal, for the prevention and/or treatment of at least one disease associated with a malfunction in maintaining haematopoiesis in a mammal, and for maintaining and expanding adult haematopoietic stem cells of said mammal, including a human. Furthermore, the present invention also relates to a method for maintaining haematopoiesis in vitro or to a method for evaluating the haematopoietic capacity of a mammal.
