"Bone marrow transplantation monitoring by DNA analysis"

Variable Number of Tandem Repeats (VNTR) DNA polymorphisms analysis was used in bone marrow transplantation (BMT) follow up. Three Acute Myeloid Leukemia (AML) transplants were investigated with YNH 24/MspI and with EFD 64.2/Rsa or HinfI highly polymorphic VNTRs. Absence of mosaicism and complete engraftment of donor cells was observed in two cases, while mixed hematopoietic chimerism was present in a case in which T cell depleted marrow was transplanted. VNTR systems represent accurate and sensitive individual specific markers for monitoring the clinical course of patients undergoing BMT, and for detecting the biological origin of relapses

"Minimal residual disease status in transplanted CML patients: low incidence of PCR positive cases among 48 disease-free subjects who received unmanipulated allogeneic bone marrow transplants"

Forty-eight long-term disease-free chronic myelogenous leukemia (CML) patients, who had received unmanipulated allogeneic bone marrow transplants (BMT) for eradication of the Philadelphia (Ph1)-positive clone were studied by polymerase chain reaction (PCR), using a very sensitive PCR procedure and very stringent criteria for preventing and revealing contamination. Nine patients (18%) were positive at the first PCR examination, but only one patient remained PCR positive four years after. However, a second PCR analysis performed on new bone marrow samples obtained at a median interval of 14 months (range 6-16) after the first specimen collection from six of nine originally positive cases, and from 16 of 39 originally negative cases, showed that only one of the six positive cases remained positive, whereas negativity was confirmed in all the originally negative patients. These data are evidence that the Ph1-positive clone is apparently completely eradicated in the majority of CML patients who survive disease-free long-term after an unmanipulated allogeneic BMT and that only sporadic cases remain PCR-positive four years post-BMT. The data also show that at least two sequential bone marrow samples for each patient must be analyzed before drawing conclusions regarding the stable persistence of BCR/ABL transcripts and the minimal residual disease status