Minimal residual disease assessment in childhood acute lymphoblastic leukemia : Results of a Swedish multi-centre study comparing real-time PCR and multi-colour flow cytometry

• In this Swedish multi-center study of early treatment response in childhood acute lymphoblastic leukemia (ALL), we evaluated the concordance between multicolour flow cytometry (FCM) and real-time quantitative polymerase chain reaction (RQ-PCR) for assessment of minimal residual disease (MRD). Multiple time points (i.e. day 15, 29, 50 and 106) were evaluated with the NOPHO (Nordic Society of Pediatric Hematology and Oncology) ALL 2000 treatment protocol as backbone. During 2002-2006, 334 children were diagnosed with ALL, where 228 had paired samples taken at any of the four time points. With the detection level of 0.1%, the concordance between RQ-PCR and FCM was 90% in the 726 paired samples analyzed. At day 29, the correlation between the methods was greater with MRD levels >0.1% (rs=0.7, p<0.001) than below (rs=0.2, p=0.024). MRD levels higher than 0.1% at day 29 was a significant predictor of higher risk of having a bone marrow relapse. This was true both for BCP ALL and T-ALL analysed with either FCM or RQ-PCR, although RQ-PCR was a better discriminator than FCM in T-ALL. However, using the NOPHO ALL 2000 protocol, our data indicate that a higher cut-off value (0.2%) should be applied in BCP ALL when using RQ-PCR as MRD method. In contrast, MRD levels ≥ 0.1%, analysed with either method late during induction therapy, was not a predictor of isolated extramedullary relapse. We therefore conclude that MRD assessment by RQ-PCR based IG/TCR rearrangement and multicolour FCM monitoring can be used as a clinical tool if the aim is to find childhood ALL cases with increased risk of having bone marrow relapses.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Nyckelord

minimal residual disease

childhood acute lymphoblastic leukemia

flow cytometry

RQ-PCR

rearranged IG/TCR genes

Pathology

Patologi

Pathology

Patologi

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)