For the past thirty years, hematology has switched from the concept of bone marrow transplantation to the concept of hematopoietic stem cell (HSC) transplantation, from allograft to autograft, from non-manipulated graft to hyper-selection, from hematopoietic cellular therapy to immunotherapy. Indications of these transplantations are now more clear for malignant diseases and are ongoing for auto-immune diseases.

A better knowledge of the HSC allows the control of their proliferation and differentiation, opening the field of ex vivo expansion.

Very recently, new stem cells have been identified, establishing that a differentiated cell retain its totipotency: a nervous system cell can differentiate into HSC, which will further give hematopoiesis, mesenchymental cells or hepatocytes.

New tools are under development: human ES cells, biomaterials, functionalized materials, opening the field of cellular engineering in the year 2000.

Douay, L. Transfus Clin Biol 1999 Dec;6(6):364-9. (Article in French).