Program Freeze and Storage of Hematopoietic Stem Cells from 1979 through 1992 at Niigata University Medical Hospital (Application of Autologous BMT to Cancer Treatment)

Our experience of a slow rate freezing of hematopoietic stem cells during 13 years is described. Harvested bone marrows were concentrated in nucleated cell rich fraction using automatic blood separators. Total 182 stem cells including 79 peripheral leukocytes in chronic myelogenous leukemia （CML）, 93 bone marrow cells in leukemias/lymphomas, gynecological and urological neoplasmas and brain tumors and 10 peripheral blood stem cells in pediatric diseases were cryopreserved in the presence of 10% dimethyl sufoxide. Freezing of circulating leukocytes in CML has been discontinued since 1981 because of eventual blastic crisis. All cells were frozen on the same program in which they were cooled at 1℃ per minute rate from 20℃ to －40℃ and then 3℃ per minute rate to －80℃. By picking up a critical freezing point of the sample and cooling the chamber, our program freezer （Ebara, RF-22R2）has always produced straight lines in lowering sample temperature. Frozen cells were kept in a liquid nitrogen stocker until their infusion. Controling sample and chamber temperature profiles is necessary for a good course after transplantation