TET2 mutations contribute to adverse prognosis in acute myeloid leukemia (AML): results from a comprehensive analysis of 502 AML cases and the Beat AML public database.

Despite the high incidence of tet methylcytosine dioxygenase 2 (TET2) mutations in acute myeloid leukemia (AML), the prognostic implications of these mutations in three AML risk groups based on the 2022 ELN AML risk classification are still unclear. A total of 502 consecutive de novo AML patients who had next-generation sequencing data available between March 2011 and July 2021 at the Peking University Institute of Hematology were enrolled in this study. Univariate and multivariate Cox regression analyses were performed to explore the prognostic impact of TET2 mutations in the above cohort and the Beat AML cohort. Of the 502 total AML patients, 76 (15.1%) carried TET2 mutations. Multivariate analysis revealed TET2 mutations as independent risk factor for overall survival (OS) in both the total AML cohort (OR = 1.649, p = 0.009) and in the 2022 ELN intermediate-risk cohort (HR = 1.967, p = 0.05). Analysis of RNA-seq data from the Beat AML study revealed 1042 differentially expressed genes (DEGs) between the TET2-mutant and TET2 wild-type groups. The results of enrichment analysis indicated the DEGs to be notably enriched in categories related to the PI3K-Akt signaling pathway. Collectively, our findings indicate that mutations in TET2 are prognostically disadvantageous in AML patients. Assessment of TET2 mutational status contributes to the stratification of intermediate-risk AML patients. Multiple genes and pathways of potential therapeutic relevance may be differentially modulated by TET2 mutations in AML.

ZNF384 fusion transcript levels for measurable residual disease monitoring in adult B-cell acute lymphoblastic leukemia.

Zinc finger protein 384 (ZNF384) rearrangement defined a novel subtype of B-cell acute lymphoblastic leukemia (B-ALL). The prognostic significance of ZNF384 fusion transcript levels represented measurable residual disease remains to be explored. ZNF384 fusions were screened out in 57 adult B-ALL patients at diagnosis by real-time quantitative polymerase chain reaction and their transcript levels were serially monitored during treatment. The reduction of ZNF384 fusion transcript levels at the time of achieving complete remission had no significant impact on survival, whereas its ≥2.5-log reduction were significantly associated with higher relapse free survival (RFS) and overall survival (OS) rates after course 1 consolidation (p = 0.022 and = 0.0083) and course 2 consolidation (p = 0.0025 and = 0.0008). Compared with chemotherapy alone, allogeneic hematopoietic stem cell transplantation (allo-HSCT) significantly improved RFS and OS of patients with <2.5-log reduction after course 1 consolidation (p < 0.0001 and = 0.0002) and course 2 consolidation (p = 0.0003 and = 0.019), whereas exerted no significant effects in patients with ≥2.5-log reduction (all p > 0.05). ZNF384 fusion transcript levels after course 1 and course 2 consolidation strongly predict relapse and survival and may guide whether receiving allo-HSCT in adult B-ALL.

The impact of donor-specific anti-HLA antibody levels on primary poor graft function and graft rejection in rituximab desensitized haploidentical stem cell transplantation.

This study investigates the influence of donor-specific anti-HLA antibodies (DSA) levels on primary poor graft function (PGF) and graft rejection (GR) after haploidentical stem cell transplantation (haplo-SCT) with rituximab desensitization. A total of 155 DSA-positive haplo-SCT candidates with mean fluorescence intensity (MFI) between 2000 and 10,000 were enrolled in this prospective clinical trial. Receiver operating characteristic (ROC) curves determined the optimal DSA MFI cutoff for identifying high-risk patients. Patients were categorized into two groups: DSA low-level group (2000 ≤ DSA MFI < 5000, Group A) and high-level group (5000 ≤ DSA MFI ≤ 10,000, Group B). The incidence of primary PGF was 6.5% (2.6%-10.3%), while GR incidence was 0.6% (0.0%-1.9%). Group A had significantly lower primary PGF rates than Group B (2.3% [0.0%-5.7%] vs. 12.9% [4.8%-21.0%], p = 0.017). Only one patient in Group B experienced GR. High DSA levels (5000 ≤ MFI ≤ 10,000) were identified as the sole independent risk factor for primary PGF and GR after haplo-SCT with rituximab desensitization (HR = 7.282, 95% CI 1.517-34.953, p = 0.013). The 4-year cumulative incidence of relapse, non-relapse mortality, disease-free survival, and overall survival were 14.7% (11.6%-17.8%), 16.3% (13.1%-19.4%), 69.0% (65.9%-76.2%), and 70.6% (66.4%-74.8%), respectively. DSA levels have an impact on efficiency of rituximab desensitization, and a DSA MFI threshold is provided for predicting primary PGF and GR.

Targeting TFH cells is a novel approach for donor-specific antibody desensitization of allograft candidates: an in vitro and in vivo study.

The presence of donor-specific antibodies (DSAs) are associated with graft failure either following HLA-mismatched allogeneic stem cell transplantation or after organ transplantation. Although targeting B cells and plasma cells have been used for desensitization, there have been reports of failure. T follicular helper (Tfh) cells assist B cells in differentiating into antibody-secreting plasma cells. We used haploidentical allograft as a platform to investigate the possibility of targeting Tfh cells to desensitize DSA. The quantities of cTfh cell subsets in allograft candidates were abnormal, and these cells, including the cTfh2 and cTfhem cell subsets, were positively related to the production of anti-HLA antibodies. Ex vivo experiments showed that the cTfh cells of anti-HLA antibody positive allograft candidates could induce B cells to differentiate into DSA-producing plasmablasts. The immune synapse could be involved in the assistance of cTfh cells to B cells in antibody production. In vitro experiments and in vivo clinical pilot studies indicated that targeting cTfh cells with sirolimus can inhibit their auxiliary function in assisting B cells. Ex vivo and in vivo studies demonstrated the effect of sirolimus and rituximab on DSA desensitization compared with either sirolimus or rituximab alone (60%, 43.75%, and 30%, respectively). Our findings provide new insight into the role of Tfh cells in the pathogenesis of DSA production in HLA-mismatched transplant candidates. Our data also indicate that targeting Tfh cells is a novel strategy for DSA desensitization and combination of sirolimus and rituximab might be a potential therapy.

The role of m6A demethylase FTO in chemotherapy resistance mediating acute myeloid leukemia relapse.

Acute myeloid leukemia (AML) is the most common hematopoietic malignancies, and chemotherapy resistance is one of the main causes of relapse. Because of lower survival rate for patients with relapse, it is pivotal to identify etiological factors responsible for chemo-resistance. In this work, direct MeRIP-seq analysis of sequential samples at stage of complete remission (CR) and relapse identifies that dysregulated N6-methyladenosine (m6A) methylation is involved in this progression, and hypomethylated RNAs are related to cell differentiation. m6A demethylase FTO is overexpressed in relapse samples, which enhances the drug resistance of AML cells in vivo and in vitro. In addition, FTO knockdown cells exhibit stronger capacity of differentiation towards granules and myeloid lineages after cytosine arabinoside (Ara-C) treatment. Mechanistically, FOXO3 is identified as a downstream target of FTO, the hypomethylation of FOXO3 mRNA affects its RNA degradation and further reduces its own expression, which ultimately result in attenuated cell differentiation. Collectively, these results demonstrate that FTO-m6A-FOXO3 is the main regulatory axis to affect the chemotherapy resistance of AML cells and FTO is a potential therapeutic target of chemotherapy resistance in AML.

CSRP2 transcript levels after consolidation therapy increase prognostic prediction ability in B-cell acute lymphoblastic leukaemia.

Quantification of measurable residual disease (MRD) correlates with the risk of leukemia recurrence in adults with B-cell acute lymphoblastic leukemia (ALL). However, it remains unknown whether collecting data on cysteine and glycine-rich protein 2 (CSRP2) transcript levels, after completing the second course of consolidation, improves prognosis prediction accuracy. A total of 204 subjects with B-cell ALL were tested for CSPR2 transcripts after completing the second course of consolidation using quantitative real-time polymerase chain reaction (qRT-PCR) and divided into high (N = 32) and low (N = 172) CSRP2 expression cohorts. In multivariable analyses, subjects with high expression of CSRP2 had a higher 5-year cumulative incidence of relapse (CIR) (hazard ratio [HR] = 2.57, 95% confidence interval [CI] 1.38-4.76; P = 0.003), lower 5-year relapse-free survival (RFS) (HR = 3.22, 95% CI 1.75-5.93; P < 0.001), and overall survival (OS) (HR = 4.59, 95% CI 2.64-7.99; P < 0.001) in the whole cohort, as well as in the multi-parameter flow cytometry (MPFC) MRD-negative cohort (for CIR, HR = 2.70, 95% CI 1.19-6.12; for RFS, HR = 4.37, 95% CI 1.94-9.85; for OS, HR = 4.90, 95% CI 2.43-9.90; all P < 0.05). Prognostic analysis showed that allogeneic hematopoietic stem cell transplantation (allo-HSCT) could significantly improve the prognosis of patients with high CSRP2 expression (allo-HSCT vs chemotherapy: 5-year CIR, 52% vs 91%; RFS, 41% vs 9%; OS, 38% vs 20%; all P < 0.05). Our data indicate that incorporating data from CSPR2 transcript levels to the MRD-testing at the end of the second course of consolidation therapy enhances prognosis prediction accuracy in adults with B-cell ALL.

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.

Mining the multifunction of mucosal-associated invariant T cells in hematological malignancies and transplantation immunity: A promising hexagon soldier in immunomodulatory.

Mucosal-associated invariant T (MAIT) cells are evolutionarily conserved innate-like T cells capable of recognizing bacterial and fungal ligands derived from vitamin B biosynthesis. Under different stimulation conditions, MAIT cells can display different immune effector phenotypes, exerting immune regulation and anti-/protumor responses. Based on basic biological characteristics, including the enrichment of mucosal tissue, the secretion of mucosal repair protective factors (interleukin-17, etc.), and the activation of riboflavin metabolites by intestinal flora, MAIT cells may play an important role in the immune regulation effect of mucosal lesions or inflammation. At the same time, activated MAIT cells secrete granzyme B, perforin, interferon γ, and other toxic cytokines, which can mediate anti-tumor effects. In addition, since a variety of hematological malignancies express the targets of MAIT cell-specific effector molecules, MAIT cells are also a potentially attractive target for cell therapy or immunotherapy for hematological malignancies. In this review, we will provide an overview of MAIT research related to blood system diseases and discuss the possible immunomodulatory or anti-tumor roles that unique biological characteristics or effector phenotypes may play in hematological diseases.

Donor CSF3R with the rs3917980A/G or G/G genotype is correlated with better leukemia-free survival after allogenic hematopoietic stem cell transplantation.

Polymorphisms in the granulocyte colony-stimulating factor receptor gene (GCSFR, CSF3R) have been reported to be associated with peripheral blood stem cell enrichment and hematological diseases. The aim of our study was to investigate the effects of donor CSF3R allelic polymorphisms on the outcomes of allogeneic stem cell transplantation. A total of 273 patients who were diagnosed with hematological diseases and treated with allogeneic hematopoietic stem cell transplantation(allo-HSCT) were enrolled in this study. Single-nucleotide polymorphisms in CSF3R were genotyped by targeted next-generation sequencing. There were six types of CSF3R genotypes with percentages over 1%. LFS and OS analyses showed that recipients receiving grafts from healthy donors with a rs3917980 G/G or A/G genotype had higher LFS rates than those receiving grafts from donors carrying a rs22754272 T/C genotype and the double-negative group (p = 0.036). Univariate cox analysis showed that donor CSF3R with the rs2275472 T/C genotype was associated with higher transplantation-related mortality (TRM) rates (HR = 2.853, 95% CI: 1.405-5.792, p = 0.00371) and lower rates of leukemia-free survival (LFS) (HR = 1.846; 95% CI: 1.018-3.347, p = 0.0435). In addition, donor CSF3R with the rs3917980G/G or A/G genotype was associated with better overall survival (OS) rates (HR = 0.560, 95% CI: 0.3162-0.9916, p = 0.047) and lower TRM rates (HR = 0.497, 95% CI: 0.2628-0.9397, p = 0.0315). Furthermore, multivariate cox analysis found that rs2275472 T/C genotype was an independent risk factors for TRM rates (HR = 3.210, 95% CI: 1.573-6.55, p = 0.001), while no statistical difference was found between rs3917980G/G or A/G genotype and clinical outcomes. Our findings demonstrate the important prognostic value of genetic variations in donor CSF3R to predict clinical outcomes in patients undergoing allo-HSCT.

Prevalence and risk factors of antibodies to HLA according to different cut-off values of mean fluorescence intensity in haploidentical allograft candidates: A prospective study of 3805 subjects.

The importance of anti-HLA antibodies in transplantation settings, such as HLA-mismatched or haploidentical hematopoietic stem cell transplantation and platelet refractoriness, is widely recognized. In previous reports, it was mentioned that several cut-off values of donor-specific anti-HLA antibodies mean fluorescence intensity (MFI) were related to graft rejection in the environment of HLA mismatched stem cell transplantation and the aim of this study was to investigate the prevalence and risk factors of anti-HLA antibodies according to those cut-off values of MFI. A total of 3805 patients with hematologic disease were prospectively enrolled and analyzed. When using MFI of anti-HLA antibodies ≥500, ≥1000, ≥1500, ≥2000, ≥5000, and ≥ 10,000 as cut-off values for positivity, the prevalence of class I or II anti-HLA antibodies ranged from 4.6% to 20.2% in all cases. When the MFI cut-off value was ≥500 for positivity, multivariate analysis indicated that platelet transfusion, underlying disease, and pregnancy were the most important risk factors for the presence of anti-HLA antibodies for the total patients. Subgroup analysis according to age, gender, and underlying disease showed that pregnancy was the most important risk factor for the presence of anti-HLA antibodies. For all patients (n = 3805), when anti-HLA antibody positivity was defined according to different MFI cut-off values, including ≥1000, ≥1500, ≥2000, ≥5000, and ≥ 10,000, an association of platelet transfusion and pregnancy with anti-HLA antibodies was also demonstrated. Our results suggest that pregnancy and platelet transfusion are the main risk factors for the prevalence of anti-HLA antibodies in haploid allograft candidates, providing evidence for guiding the evaluation of anti-HLA antibodies and helping donor selection for HLA-mismatched transplant candidates.

Independent prognostic significance of TP53 mutations in adult acute myeloid leukaemia with complex karyotype.

INTRODUCTION: Adult acute myeloid leukaemia (AML) patients with complex karyotype (CK) generally have unfavourable outcomes. CK commonly co-exists with characteristic chromosomal and genetic abnormalities such as monosomal karyotype (MK), -17 or 17p- [abn(17p)] and TP53 mutations. Their individual prognostic significance needs to be clarified. METHODS: Seventy-three adult CK-AML patients and eleven adult non-CK-AML patients with TP53 mutations (non-CK/TP53mu ) who were diagnosed and received therapy at our institute were enrolled. One hundred and fifty-seven AML cases retrieved from the cancer genome atlas (TCGA) for validation. RESULTS: Among CK-AML patients, those with TP53 mutations (CK/TP53mu ) had significantly lower rates of 1-course induction complete remission (CR), 2-year relapse-free survival (RFS) and 2-year overall survival (OS) than those without TP53 mutations (CK/TP53wt ); whereas, abn(17p) did not have the above impacts; MK was significantly associated with a lower 2-year OS rate but was not related to the rates of CR and RFS. Multivariate analysis showed that it were TP53 mutations and treating with chemotherapy alone but not MK and abn(17p) that independently predicted the adverse prognosis for RFS and OS in CK-AML. Furthermore, non-CK/TP53mu patients showed similar rates of CR, RFS and OS to CK/TP53mu patients. Validation using the TCGA cohort showed that CK/TP53mu patients had a significantly lower 2-year OS rate than CK/TP53wt patients, whereas abn(17p) and MK did not impact OS; the 2-year OS rate of patients with CK/TP53wt was similar to that of patients with intermediate-risk cytogenetics. CONCLUSION: Adult CK-AML patients have varied risks and TP53 mutations seem to be an independent adverse prognostic factor.

CMV infection combined with acute GVHD associated with poor CD8+ T-cell immune reconstitution and poor prognosis post-HLA-matched allo-HSCT.

Cytomegalovirus (CMV) infection and acute graft-versus-host disease (aGVHD) are two major complications that contribute to a poor prognosis after hematopoietic stem cell transplantation (HSCT). Superior early immune reconstitution (IR) is associated with improved survival after HSCT. However, when all three factors, CMV infection, aGVHD, and IR, are concomitantly considered, the effects of the triple events on HSCT are still unknown and should be studied further. Thus we enrolled 185 patients who were diagnosed as hematological malignancies and treated with HLA-matched sibling transplantation (MST) between January 2010 and December 2014, of whom 83 were positive for CMV infection and 82 had aGVHD. Results showed that patients with both aGVHD and CMV infection had significantly higher non-relapse mortality (NRM), lower overall survival (OS), and delayed CD8+ T-cell IR. Multivariate analyses showed that both aGVHD combined with CMV infection and delayed CD8+ T-cell IR were independent risk factors for prognosis post-MST. Recurrent CMV infections are associated with poor CD8+ T-cell reconstitution. However, superior IR could protect against the negative effects of aGVHD and CMV infection on the transplant outcomes.

Combination of KIT and FLT3-ITD mutation status with minimal residual disease levels guides treatment strategy for adult patients with inv(16) acute myeloid leukemia in first complete remission.

Although several studies have investigated the benefits of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with inv (16) acute myeloid leukemia (AML) in first complete remission (CR1) individually stratified by KIT or FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutation status or minimal residual disease (MRD) levels, evaluation based on the combination of mutation status and MRD levels remains absent. This study included 157 adult patients with inv (16) AML who were consecutively diagnosed and receiving treatment at our center. A total of 50 (31.6%) patients had KIT mutations (KITMU ), and the risk of relapse was significantly higher in patients with KITMU than in patients with KITWT (p < 0.001). A total of 12 patients (7.6%) had FLT3-ITD, and FLT3-ITD+ tended to be related to a higher risk of relapse (p = 0.14). KITMU , FLT3-ITD and MRD3-H (beta subunit of core binding factor-myosin heavy chain 11 levels >0.2% after course 2 of consolidation therapy) were independent adverse prognostic factors for relapse with patients who received allo-HSCT at CR1 were censored at the time of transplantation. After combination, patients were categorized into molecularly defined high-risk (M-HR; KITMU or FLT3-ITD+ with MRD3-H; n = 30), low-risk (M-LR; KITWT and FLT3-ITD- with MRD3-L; n = 45) and intermediate-risk (M-IR; others; n = 70) groups. For the M-HR group, allo-HSCT significantly improved both cumulative incidence of relapse cumulative incidence of relapse (CIR) and overall survival (OS) (11.1% vs. 92.6%, p < 0.001; 90.0% vs. 34.1%, p = 0.019). For the M-IR group, allo-HSCT significantly improved CIR but did not affect OS (14.1% vs. 62.2%, p = 0.0004; 73.3% vs. 68.3%, p = 0.43). For the M-LR group, allo-HSCT had no significant effect on both CIR and OS (0% vs. 35.1%, p = 0.31; 100% vs. 78.8%, p = 0.22). Therefore, the combination of KIT and FLT3-ITD mutation status with MRD levels may identify inv (16) AML patients with high-risk who can benefit from allo-HSCT in CR1.

The Interaction of HLA-C1/KIR2DL2/L3 Promoted KIR2DL2/L3 Single-Positive/NKG2C-Positive Natural Killer Cell Reconstitution, Raising the Incidence of aGVHD after Hematopoietic Stem Cell Transplantation.

NKG2C+ natural killer (NK) cell plays a vital role in CMV infection control after hematopoietic stem cell transplantation (HSCT). However, the modulation on NKG2C+ NK cell reconstitution is still unclear. NK cell education is affected by the interactions of HLA-I/killer immunoglobulin receptor (KIR). Our aim is to figure out which HLA-I/KIR interaction plays a dominant role in NKG2C+ NK education. Based on allogeneic haploidentical HSCT, we investigated the expansion and function of single KIR positive NKG2C+ NK cells via the interaction of KIR with both donor HLA and recipient HLA at days 30, 90, and 180 after HSCT. KIR2DL2/L3 single-positive/NKG2C+ cells were significantly expanded compared with KIR2DL1 or KIR3DL1 single-positive/NKG2C+ cells when donors and recipients were both HLA-C1/C1 or HLA-C1C1BW4 (p < 0.05), with higher NKp30 expression (p < 0.05). Moreover, the proportion of single KIR positive NK cells increased in both NKG2C+/NKG2A- NK cells and conventional NKG2C-/NKG2A- NK cells over time. We also observed that increased proportion of KIR2DL2/L3 single-positive/NKG2C+ NK cells correlated with higher incidence of acute graft-versus-host disease (aGVHD). Our study allows a better understanding of HLA-I/KIR interaction in the NKG2C+ NK cell education after HSCT.

Recipient and donor PTX3 rs2305619 polymorphisms increase the susceptibility to invasive fungal disease following haploidentical stem cell transplantation: a prospective study.

BACKGROUND: Invasive fungal disease (IFD) is a severe complication after haploidentical stem cell transplantation (haplo-HSCT) and has a poor prognosis. It has been shown that genetic polymorphism may be one possible reason for the increased risk of IFD. This study aimed to assess the role of genetic polymorphism in the level of susceptibility to IFD after haplo-HSCT. METHODS: In this study, we prospectively enrolled 251 patients who received haplo-HSCT at the Peking University Institute of Hematology from 2016 to 2018. Forty-three single nucleotide polymorphisms (SNPs) of the genomic DNA were genotyped in blood samples from both recipient and donor. RESULTS: Twenty-two patients (8.8%) were diagnosed with proven or probable IFD. The independent risk factors for IFD were grades 3-4 acute graft-versus-host disease, cytomegalovirus reactivation, and recipient and donor rs2305619 (PTX3) (P < 0.05) in multivariate analysis. Meanwhile, we combined the variables to develop the IFD risk scoring system and stratified patients into low- (0-2) and high-risk (3-4) groups. The 30-day and 100-day cumulative incidence of IFD in the low- and high-risk groups were 2.1% and 10.2%, 4.2% and 20.3%, respectively (P = 0.015). CONCLUSIONS: PTX3 rs2305619 polymorphism increase the susceptibility of IFD after haplo-HSCT in the Chinese Han population, and the IFD scoring system could be useful in risk stratification for IFD after HSCT.

Preemptive Interferon-α Therapy Could Protect Against Relapse and Improve Survival of Acute Myeloid Leukemia Patients After Allogeneic Hematopoietic Stem Cell Transplantation: Long-Term Results of Two Registry Studies.

For allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, preemptive interferon-α (IFN-α) therapy is considered as a useful method to eliminate the minimal residual disease (MRD). Our purpose is to assess the long-term efficacy of preemptive IFN-α therapy in acute myeloid leukemia (AML) patients following allo-HSCT based on two registry studies (#NCT02185261 and #NCT02027064). We would present the final data and unpublished results of long-term clinical outcomes with extended follow-up. We adopted polymerase chain reaction (PCR) and multiparameter flow cytometry (MFC) to monitor MRD, and a positive result of bone marrow specimen examined by either of them would be identified as the MRD-positive status. Subcutaneous injections of recombinant human IFN-α-2b were performed for 6 cycles, and prolonged IFN-α therapy could be permitted at the request of patients. The median cycles were 3.5 (range, 0.5-30.5) cycles. A total of 9 patients suffered from grade ≥3 toxicities (i.e., infectious: n = 6; hematologic: n = 3). The 6-year cumulative incidences of relapse and non-relapse mortality following IFN-α therapy were 13.0% (95% confidence interval [CI], 5.4-20.6%) and 3.9% (95%CI, 0.0-17.6%), respectively. The probability of disease-free survival at 6 years following IFN-α therapy was 83.1% (95%CI, 75.2-91.9%). The probability of overall survival at 6 years following IFN-α therapy was 88.3% (95%CI, 81.4-95.8%). The cumulative incidences of total chronic graft-versus-host disease (cGVHD) and severe cGVHD at 6 years following IFN-α therapy were 66.2% (95%CI, 55.5-77.0%) and 10.4% (95%CI, 3.6-17.2%), respectively. Multivariable analysis showed that an alternative donor was associated with a lower risk of relapse and the better disease-free survival. Thus, preemptive IFN-α therapy could clear MRD persistently, prevent relapse truly, and improve long-term survival in AML patients following allo-HSCT.

Donor NKG2C homozygosity contributes to CMV clearance after haploidentical transplantation.

CMV infection remains an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Several investigators have reported that adaptive NKG2C+ NK cells persistently expand during CMV reactivation. In our study, 2 cohorts were enrolled to explore the relationships among the NKG2C genotype, NKG2C+ NK cell reconstitution, and CMV infection. Multivariate analysis showed that donor NKG2C gene deletion was an independent prognostic factor for CMV reactivation and refractory CMV reactivation. Furthermore, adaptive NKG2C+ NK cells' quantitative and qualitative reconstitution, along with their anti-CMV function after transplantation, was significantly lower in patients grafted with NKG2Cwt/del donor cells than in those grafted with NKG2Cwt/wt donor cells. At day 30 after transplantation, quantitative reconstitution of NKG2C+ NK cells was significantly lower in patients with treatment-refractory CMV reactivation than in patients without CMV reactivation and those with nonrefractory CMV reactivation. In humanized CMV-infected mice, we found that, compared with those from NKG2Cwt/del donors, adaptive NKG2C+ NK cells from NKG2Cwt/wt donors induced earlier and stronger expansion of NKG2C+ NK cells as well as earlier and stronger CMV clearance in vivo. In conclusion, donor NKG2C homozygosity contributes to CMV clearance by promoting the quantitative and qualitative reconstruction of adaptive NKG2C+ NK cells after haploidentical allo-HSCT.

Monitoring of post-transplant MLL-PTD as minimal residual disease can predict relapse after allogeneic HSCT in patients with acute myeloid leukemia and myelodysplastic syndrome.

BACKGROUND: The mixed-lineage leukemia (MLL) gene is located on chromosome 11q23. The MLL gene can be rearranged to generate partial tandem duplications (MLL-PTD), which occurs in about 5-10% of acute myeloid leukemia (AML) with a normal karyotype and in 5-6% of myelodysplastic syndrome (MDS) patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently one of the curative therapies available for AML and MDS with excess blasts (MDS-EB). However, how the prognosis of patients with high levels of MLL-PTD after allo-HSCT, and whether MLL-PTD could be used as a reliable indicator for minimal residual disease (MRD) monitoring in transplant patients remains unknown. Our study purposed to analyze the dynamic changes of MLL-PTD peri-transplantation and the best threshold for predicting relapse after transplantation. METHODS: We retrospectively collected the clinical data of 48 patients with MLL-PTD AML or MDS-EB who underwent allo-HSCT in Peking University People's Hospital. The MLL-PTD was examined by real-time quantitative polymerase chain reaction (RQ-PCR) at the diagnosis, before transplantation and the fixed time points after transplantation. Detectable MLL-PTD/ABL > 0.08% was defined as MLL-PTD positive in this study. RESULTS: The 48 patients included 33 AML patients and 15 MDS-EB patients. The median follow-up time was 26(0.7-56) months after HSCT. In AML patients, 7 patients (21.2%) died of treatment-related mortality (TRM), 6 patients (18.2%) underwent hematological relapse and died ultimately. Of the 15 patients with MDS-EB, 2 patients (13.3%) died of infection. The 3-year cumulative incidence of relapse (CIR), overall survival (OS), disease-free survival (DFS) and TRM were 13.7 ± 5.2, 67.8 ± 6.9, 68.1 ± 6.8 and 20.3% ± 6.1%, respectively. ROC curve showed that post-transplant MLL-PTD ≥ 1.0% was the optimal cut-off value for predicting hematological relapse after allo-HSCT. There was statistical difference between post-transplant MLL-PTD ≥ 1.0% and MLL-PTD < 1.0% groups (3-year CIR: 75% ± 15.3% vs. 0%, P < 0.001; 3-year OS: 25.0 ± 15.3% vs. 80.7% ± 6.6%, P < 0.001; 3-year DFS: 25.0 ± 15.3% vs. 80.7 ± 6.6%, P < 0.001; 3-year TRM: 0 vs. 19.3 ± 6.6%, P = 0.277). However, whether MLL-PTD ≥ 1% or MLL-PTD < 1% before transplantation has no significant difference on the prognosis. CONCLUSIONS: Our study indicated that MLL-PTD had a certain stability and could effectively reflect the change of tumor burden. The expression level of MLL-PTD after transplantation can serve as an effective indicator for predicting relapse.