Prediction model for CD34 positive cell yield in peripheral blood stem cell collection on the fourth day after G-CSF administration in healthy donors.

Allogeneic peripheral blood stem cell transplantation (PBSCT) is an indispensable treatment option for hematological malignancy. The optimal collection day after granulocyte colony-stimulating factor (G-CSF) administration should be determined by peripheral blood pre-apheresis CD34 positive (CD34⁺) cell percentage. However, pre-apheresis CD34⁺ cell analysis is not available for most institutions in Japan. Prediction of the optimal collection day based on objective parameters, other than direct CD34⁺ cell count, is thus an important matter for investigation. To identify potential predictive factors, clinical parameters in 79 related donors who received allogeneic peripheral blood stem cell (PBSC) collection were analyzed. Eight factors were significantly correlated with the number of CD34⁺ cells per donor body weight on the fourth day (day 4) after G-CSF administration in univariate analysis. Using multi-regression analysis, we made a simple scoring system comprising age, sex, LDH on day 4 and RBC count at the baseline, which significantly predicted CD34⁺ cell yield (P = 0.048). This system allows us to determine the optimal PBSC collection day. When the score is 0 or 1 on day 4, starting apheresis on day 5 potentially helps avoiding the need for multiple harvests. Score 3 or 4 on day 4 is indicative of better performance if apheresis is started on day 4.