Correlation of hematologic recovery with CFU-GM content of autologous bone marrow grafts treated with 4-hydroperoxycyclophosphamide. Culture after cryopreservation

We previously described an exponential correlation of the CFU-GM content of 4-hydroperoxycyclophosphamide-treated autologous bone marrow grafts and the rate of hematologic recovery of the recipients after transplantation. Those grafts were assayed before cryopreservation. We now describe a similar analysis based upon cultures of the thawed bone marrow. In a proportional hazards model, the CFU-GM content of the grafts sampled after thawing predicted time to achieving a peripheral blood count of 1 x 10⁹/l leukocytes, 0.5 x 10⁹/l granulocytes, 2% reticulocytes, and last platelet transfusion (p < 0.001). Using linear regression analysis, the logarithm of the CFU-GM content/kg of recipient weight also was correlated with the time to achieving 1 x 10⁹/l leukocytes (r = -0.62), and 0.5 x 10⁹/l granulocytes (r = -0.66). The hazard ratios (Cox model) and regression coefficients (linear regression model) for the equations calculated from the post-thaw cultures were usually smaller than the corresponding coefficients based upon the pre-freeze cultures, suggesting that pre-freeze cultures may be more accurate predictors of aplasia duration. However, patients with poor post-freeze survival of CFU-GM were more likely to experience delayed engraftment. Therefore, the correlation of post-thaw cultures with engraftment may permit the analysis of cryopreservation techniques.