Hypothesis-generating data. (A) Correlation between day 5 peripheral blood (PB) concentration of CD34+ cells ([CD34+]) and concentration of CD34+CD38– cells ([CD34+CD38–]) (in cells/μl). The r value was obtained using Pearson correlation. (B) Kaplan–Meier probability of relapse based on day 5 PB [CD34+CD38–] <10/μl or >10/μl. Probabilities of relapse were estimated using the Kaplan–Meier product limit method with comparison between groups evaluated by the log-rank statistic.