Minimal residual disease monitoring and preemptive immunotherapies for frequent 11q23 rearranged acute leukemia after allogeneic hematopoietic stem cell transplantation

Single-cell immune landscape of measurable residual disease in acute myeloid leukemia

Measurable residual disease (MRD) is a powerful prognostic factor of relapse in acute myeloid leukemia (AML). We applied the single-cell RNA sequencing to bone marrow (BM) samples from patients with (n=20) and without (n=12) MRD after allogeneic hematopoietic stem cell transplantation. A comprehensive immune landscape with 184,231 cells was created. Compared with CD8+ T cells enriched in the MRD-negative group (MRD-_CD8), those enriched in the MRD-positive group (MRD+_CD8) showed lower expression levels of cytotoxicity-related genes. Three monocyte clusters (i.e., MRD+_M) and three B-cell clusters (i.e., MRD+_B) were enriched in the MRD-positive group. Conversion from an MRD-positive state to an MRD-negative state was accompanied by an increase in MRD-_CD8 clusters and vice versa. MRD-enriched cell clusters employed the macrophage migration inhibitory factor pathway to regulate MRD-_CD8 clusters. These findings revealed the characteristics of the immune cell landscape in MRD positivity, which will allow for a better understanding of the immune mechanisms for MRD conversion.

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients With Acute Myeloid Leukemia Harboring KMT2A Rearrangement and Its Prognostic Factors

KMT2A rearrangement (KMT2A-r) in patients with acute myeloid leukemia (AML) is associated with poor outcomes; the prognostic factors after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain unclear. We investigated 364 adults with AML who underwent allo-HSCT between April 2016 and May 2022, and 45 had KMT2A-r among them. Propensity score analysis with 1:1 matching and the nearest neighbor matching method identified 42 patients in KMT2A-r and non-KMT2A-r cohorts, respectively. The 2-year overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and non-relapsed mortality rates of patients with KMT2A-r (n = 45) were 59.1%, 49.6%, 41.5%, and 8.9%, respectively. Using propensity score matching, the 2-year OS rate of patients with KMT2A-r (n = 42) was lower than that of those without KMT2A-r (n = 42; 56.1% vs 88.1%, P = 0.003). Among patients with KMT2A-r (n = 45), the prognostic advantage was exhibited from transplantation in first complete remission (CR1) and measurable residual disease (MRD) negative, which was reflected in OS, RFS, and CIR (P < 0.001, P < 0.001, and P = 0.002, respectively). Furthermore, patients with AF6 had poorer outcomes than those with AF9, ELL, and other KMT2A-r subtypes (P = 0.032, P = 0.001, and P = 0.001 for OS, RFS, and CIR, respectively). However, no differences were found in the OS, RFS, and CIR between patients with KMT2A-r with and without mutations (all P > 0.05). Univariate and multivariate analyses revealed that achieving CR1 MRD negative before HSCT was a protective factor for OS [hazard ratio (HR) = 0.242, P = 0.007], RFS (HR = 0.350, P = 0.036), and CIR (HR = 0.271, P = 0.021), while AF6 was a risk factor for RFS (HR = 2.985, P = 0.028) and CIR (HR = 4.675, P = 0.004). The prognosis of patients with KMT2A-r AML was poor, particularly those harboring AF6-related translocation; however, it is not associated with the presence of mutations. These patients can benefit from achieving CR1 MRD negative before HSCT.

The adverse impact of ecotropic viral integration site-1 (EVI1) overexpression on the prognosis of acute myeloid leukemia with KMT2A gene rearrangement in different risk stratification subtypes

INTRODUCTION

AML patients with KMT2A-MLLT3 and other 11q23 abnormalities belong to the intermediate and high-risk level groups, respectively. Whether the poor prognostic value of Ecotropic Viral Integration site-1 (EVI1) overexpression suits either the subtypes of KMT2A-MLLT3 or Non-KMT2A-MLLT3 AML patients (intermediate and high risk group) needs to be further investigated.

METHODS

We retrospectively analyzed the clinical characteristics of 166 KMT2A-r and KMT2A-PTD AML patients.

RESULTS

For the Non-KMT2A-MLLT3 group, patients in the EVI1-high subgroup had shorter OS and DFS and higher CIR than those in the EVI1-low subgroup (p = .027, p = .018, and p = .020, respectively). Additionally, both KMT2A-MLLT3 and Non-KMT2A-MLLT3 patients who received chemotherapy alone had poorer prognosis than patients who also received allogeneic hematopoietic stem cell transplant (allo-HSCT) regardless of their EVI1 expression level (all p < .001). For transplanted patients with KMT2A-MLLT3 or Non-KMT2A-MLLT3 rearrangement, the EVI1-high subgroup had worse prognosis than the EVI1-low subgroup (all p < .05). The 2-year CIR of the KMT2A-MLLT3 and Non-KMT2A-MLLT3 groups with high EVI1 expression was high (52% and 49.6%, respectively). However, for patients with low EVI1 expression, the 2-year CIR of transplanted patients with KMT2A-MLLT3 and Non-KMT2A-MLLT3 was relatively low.

CONCLUSIONS

Our study showed that for the Non-KMT2A-MLLT3 group, the EVI1-high group had shorter OS and DFS than the EVI1-low group. High EVI1 expression showed an adverse effect in AML with KMT2A rearrangement in different risk stratification subtypes. For the EVI1-high patients with non-KMT2A-MLLT3 rearrangement, other novel regimens towards relapse should be taken into consideration.