Relevance of clonogenic assays in hematotoxicology

Clonogenic assays have been established in hematology for 30 years. They ha ve been widely used in fundamental studies on hematopoiesis and they are al so routinely used in clinical hematology to confirm diagnosis or to predict time to recovery in cases of bone marrow failure. Their use in toxicologic al studies is more recent. Adverse effects of xenobiotics can induce hemato logical problems and pathologies such as neutropenia, thrombocytopenia, ane mia, and aplastic anemia. Three clonogenic assays are proposed for granulop oiesis, megakaryopoieisis and erythropoieisis. Hematopoietic progenitors fr om murine or human origin can be cultured in the presence of xenobiotics us ing validated protocols to complete standard animal toxicological studies. These clonogenic assays can help to predict adverse effects of drugs or tox icants. Clonogenic assays using white blood cell progenitors (CFU-GM cultur e) have recently been validated by ECVAM and can be used routinely. Megakar yocyte progenitor (CFU-MK) culture is under development and prevalidation i n toxicological studies supported by ECVAM. Red blood cells progenitor cult ure (BFU-E) has been proposed but needs international validation to be reco gnized.