Cryopreservation of human bone marrow after purging T-cells or tumor cells.

Bone marrow transplantation (BMT) is a valuable measure for treatment of leukemia. In order to reduce, even to eliminate, the graft versus host disease after allogenic BMT and prevent the reinfusion of tumor cells during autologous BMT, the cryopreservation of human BM after purging T-cells with immunotoxin or purging tumor cells with monoclonal antibody 55 (McAb55) was studied. Results demonstrated that: (1) treatment with McAb55 and rabbit complement (RC) did not affect the GM-CFU of BM, but treatment with immunotoxin slightly decreased the GM-CFU of BM; (2) a freeze-thawing procedure obviously decreased the GM-CFU number of BM, the GM-CFU numbers of frozen BM samples were lower than those of the nonfrozen samples; (3) there were no differences in GM-CFU numbers between normal BM and BM treated with McAb55 and RC when the cooling rate used was the same; (4) there was a negative linear correlation between cooling rates and GM-CFU numbers of BM in the cooling rate range used and the optimal cooling rate for the cryopreservation of normal BM and BM treated with McAb55 and RC or immunotoxin was the same, namely, 0.5 degrees C/min.