Annalisa Paviglianiti, Clinical Hematology Department, Institut Català d'Oncologia-Hospitalet, Barcelona, Spain, comments on the publication entitled “Deep sequencing in CD34+ cells from peripheral blood enables sensitive detection of measurable residual disease in AML” published in Blood Advances
Deep sequencing in CD34+ cells from peripheral blood enables sensitive detection of measurable residual disease in AML
Sebastian Stasik et al.
Blood Adv. 2022 Jun 14;6(11):3294-3303. doi: 10.1182/bloodadvances.2021006233.
AlloHSCT is a curative option for AML and high-risk MDS, but relapse can occur in 30 to 60% of the cases. Monitoring measurable residual disease (MRD) may help identifying patients who would benefit from treatment intensification. Current MRD techniques, such as flow cytometry or quantitative PCR, are available for AML with specific mutations accounting less than 50% of patients. In contrast, next-generation sequencing (NGS) can detect all types of molecular specific alterations. The authors evaluated the feasibility of a novel approach for MRD detection in peripheral blood (PB), which combines immunomagnetic preenrichment and fluorescence-activated cell sorting (FACS) for isolation of CD34+ cells with error-reduced targeted NGS.
A total of 40 patients with AML or high-risk MDS, with or without molecular relapse based on CD34+ donor chimerism (DC), in complete remission after alloHSCT were included. The authors retrospectively analysed 429 PB and 55 bone marrow (BM) specimen of these patients for clinical validation. Enrichment of CD34+ cells for NGS increased the detection of mutant alleles in PB (P < .0001). The combination of FACS and NGS improved sensitivity for MRD detection in dilution experiments of 10-fold to levels of 10-6.
In both assays, MRD detection was superior using PB versus BM for CD34+ enrichment. NGS on CD34+ PB cells was able to predict molecular relapse with high sensitivity (100%) and specificity (91%), and significantly earlier than by CD34+ DC or NGS of unsorted PB (median of 48 [range 0-281] days, P = .0011). Moreover, NGS panel analysis in CD34+ cells allowed for the early assessment of clonal trajectories in haematological complete remission.
Stasik et al. report a novel and easily accessible method for MRD detection in AML patients undergoing alloHSCT. Such a MRD monitoring, demonstrating high sensitivity and specificity, could help in the case of patients with AML lacking a suitable molecular marker. Importantly, thanks to this new NGS-based methods, early prediction of disease recurrence can be documented. This could help in MRD guided preemptive strategies after alloHSCT. Furthermore, due to the many new available target drugs (IDH inhibitors, CD 47 antibodies and others) a higher sensitivity in MRD detection is of special interest in the near future. The paper reminds us that the assessment of response and the depth we are able to detect is an evolving concept as far as we will be able to in-depth our knowledge into the molecular basis of AML.
Bibliography
1) Tsirigotis P, Byrne M, Schmid C, et al. Relapse of AML after hematopoietic stem cell transplantation: methods of monitoring and preventive strategies. A review from the ALWP of the EBMT. Bone Marrow Transplant. 2016;51(11):1431-1438
2) Thiede C, Bornhäuser M, Oelschlägel U, et al. Sequential monitoring of chimerism and detection of minimal residual disease after allogeneic blood stem cell transplantation (BSCT) using multiplex PCR amplification of short tandem repeat-markers. Leukemia. 2001;15(2):293-302
3) Jongen-Lavrencic M, Grob T, Hanekamp D, et al. Molecular minimal residual disease in acute myeloid leukemia. N Engl J Med. 2018;378(13):1189-1199
4) Getta BM, Devlin SM, Levine RL, et al. Multicolor flow cytometry and multigene next-generation sequencing are complementary and highly predictive for relapse in acute myeloid leukemia after allogeneic transplantation. Biol Blood Marrow Transplant. 2017;23(7):1064-1071
5) Onecha E, Rapado I, Luz Morales M, et al. Monitoring of clonal evolution of acute myeloid leukemia identifies the leukemia subtype, clinical outcome and potential new drug targets for post-remission strategies or relapse. Haematologica. 2021;106(9):2325-2333.