The kinetics of donor microchimerism was detected in all 4 female patients (range, 0.000033-0.0009 gene expression copies) compared with the internal control gene β-globin (1.0 copy). The kinetics of donor microchimerism showed that microchimerism emerged on day 2 and reached its first peak on days 7-14 after the first G-PBSC treatment and its second peak after the second or third course of G-PBSC therapy, lasting 2 weeks to 10 months.