Stem cell transplantation in poor-risk chronic lymphocytic leukemia: assessment of post-transplant minimal residual disease using four- and six-color flow cytometry and allele-specific RQ-PCR.
A total of 178 bone marrow samples were taken for minimal residual disease (MRD) analysis after 34 stem cell transplantations for poor-risk chronic lymphocytic leukemia, and 86 of them were analyzed in parallel by flow cytometry and allele-specific oligonucleotide-PCR (ASO-PCR). ASO primer was successfully designed for all patients whose frozen diagnosis samples were available. Flow cytometry and ASO-PCR were concordant, i.e. both either positive or both negative, in 78% of the analyses. Flow cytometry did not detect MRD in any of the samples that were PCR-negative cases. In contrast, ASO-PCR detected MRD in samples that were negative for MRD by flow cytometry in 22% of the analyses. In one patient, the immunophenotype but not the IgV(H) gene sequence had changed during a course of the disease, and MRD could not be followed by flow cytometry. In the remaining cases, the discrepancy was due to a higher sensitivity of ASO-PCR. Autologous stem cell transplantation resulted in clinical complete response in 87% (20/23) of the patients. By flow cytometry, 35% (8/23) of autotransplanted patients became MRD-negative, but only 12.5% (2/16) PCR-negative (sensitivity of ASO-PCR <0.001 and <0.01, respectively). All allotransplanted patients achieved or maintained hematological CR, and five out of nine patients (56%) became PCR-negative (sensitivity of PCR between <0.001 and <0.003), two of them having non-myeloablative conditioning. None of the patients who became PCR-negative after allogeneic transplantation have relapsed.
Itälä
Maija
M
Department of Medicine, Turku University Central Hospital, Turku, Finland. maija.itala@tyks.fi
Huhtinen
Anna-Riina
AR
Juvonen
Vesa
V
Kairisto
Veli
V
Pelliniemi
Tarja-Terttu
TT
Penttilä
Tarja-Leena
TL
Rauhala
Auvo
A
Tienhaara
Anri
A
Remes
Kari
K
D000368:Aged; D001856:Bone Marrow Examination; D005260:Female; D005434:Flow Cytometry / Q000379:methods* / Q000592:standards; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis*; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards*; D018570:Risk Assessment; D019172:Transplantation Conditioning / Q000379:methods; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous