Donor-derived abnormal lymphocytes after haplo-PBSCT. (A) Three years after haplo-PBSCT, donor-derived lymphocytes with nuclear abnormalities, such as lobulation, were observed in peripheral blood of the patient (recipient); Wright-Giemsa staining, original magnification ×400. (B) HTLV-I Southern blot analysis of donor-derived abnormal lymphocytes, digested by EcoRI (E) and PstI (P). Lanes 1 and 2, positive control; lanes 3 and 4, negative control; lanes 5 and 6, the patient’s (recipient’s) sample. M, size marker.