Reliable quantification of hematopoietic chimerism after allogeneic transplantation for acute leukemia using amplification by real-time PCR of null alleles and insertion/deletion polymorphisms.
Increasing mixed chimerism (MC) after allogeneic stem cell transplantation (SCT) has been associated with a high risk of relapse in acute leukemia. We evaluated a new method for chimerism detection, based on the quantitative real-time PCR (qrt-PCR) amplification of null alleles or insertion/deletion polymorphisms (indels). All qrt-PCR assays with null alleles and indels attained a sensitivity of at least 10(-4), as well as good intra- and interassay concordance, and a high accuracy in experiments with cell mixtures. Informativeness was found in 80.3% of the 61 donor/recipient pairs tested. Nonrelapsed patients showed a progressive decrease in peripheral blood chimerism to values below 0.01% (complete chimerism (CC)). Bone marrow chimerism failed to reach CC more than 4 years after SCT. Increasing MC was observed prior to relapse in 88.2% of patients. Compared with conventional PCR amplification of variable number of tandem repeats, qrt-PCR predicted a significantly higher number of relapses (88.2 vs 44.4%) with a median anticipation period of 58 days. In conclusion, chimerism determination by qrt-PCR amplification of null alleles and indels constitutes a useful tool for the follow-up of patients with acute leukemia after SCT, showing better results than those obtained with conventional PCR.
Jiménez-Velasco
A
A
Hematology Department, Carlos Haya Hospital, Málaga, Spain. antoniof.jimenez.sspa@juntadeandalucia.es
Barrios
M
M
Román-Gómez
J
J
Navarro
G
G
Buño
I
I
Castillejo
J A
JA
Rodríguez
A I
AI
García-Gemar
G
G
Torres
A
A
Heiniger
A I
AI
D000293:Adolescent; D000328:Adult; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000032:analysis / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D018183:Transplantation Chimera / Q000097:blood* / Q000235:genetics
D004247:DNA