Carolina Martínez-Laperche

Prognostic impact of minimal residual disease analysis by flow cytometry in patients with acute myeloid leukemia before and after allogeneic hemopoietic stem cell transplantation

Allogeneic stem cell transplantation (allo‐SCT) has become the treatment of choice in patients with intermediate‐risk and high‐risk acute myeloid leukemia (AML). The quality of response to treatment, assessed in terms of detection of minimal residual disease (MRD), has been consistently associated with prognosis and clinical outcome in patients with AML. The aim of the present study was to evaluate the prognostic impact of analyzing MRD in bone marrow using 4‐color multiparametric flow cytometry (MFC) in 29 patients with AML before and after allo‐SCT. Eighteen patients who were shown to be MRD‐negative [≤0.1% leukemia‐associated immunophenotypes (LAIPs)] by MFC at transplantation and underwent allo‐SCT had lower rates of relapse (15% vs. 66%, P = 0.045), better overall 1‐yr survival (83% vs. 52%, P = 0.021) and a lower cumulative incidence of relapse (P = 0.032) than patients who were MRD‐positive (>0.1%). All post‐transplant MRD‐positive patients underwent a therapeutic intervention after transplant (tapering of immunosuppression, donor lymphocyte infusion, or re‐transplant) with the intention of preventing relapse. Disease was controlled and MRD disappeared in five of these patients. Disease recurred in the other seven patients. We can conclude that follow‐up with MFC for the detection of MRD in AML before and after SCT is useful for predicting relapse. In the post‐transplant setting, monitoring of MRD by MFC could be a key preemptive intervention.

Donor CTLA-4 genotype influences clinical outcome after T cell-depleted allogeneic hematopoietic stem cell transplantation from HLA-identical sibling donors.

CTLA-4 (cytotoxic T-lymphocyte antigen-4) plays a pivotal role in inhibiting T cell activation through competitive interaction with B7 molecules and interruption of costimulatory signals mediated by CD28. Polymorphisms on the CTLA-4 gene have been previously associated with autoimmune diseases, predisposition to leukemic relapse, and with graft-versus-host disease (GVHD) or relapse after allogeneic transplant. As CTLA-4 is expressed on T-lymphocytes, the aim of this study was to determine whether the donor CTLA-4 CT60 genotype also influences clinical outcome even after T cell depletion with CD34-positive selection. We studied 136 patient-donor pairs. Overall survival (OS) was worse for those patients who received grafts from a donor with the CT60 AA genotype rather than from a donor with the AG or GG genotype (35.6% vs 49.4%; P = .043). This association was confirmed through multivariate analysis, which identified the donor CT60 genotype as an independent risk factor for OS (P = .008; hazard ratio [HR]: 2.24, 95% confidence interval [CI]: 1.23-4.08). The donor CT60 AA genotype was also associated with lower disease-free survival, this being related to an increased risk of relapse (P = .001; HR: 3.41, 95% CI: 1.67-6.96) and a trend toward higher transplant-related mortality. These associations were stronger when considering only patients in the early stage of disease. Our results suggest that graft-versus-leukemia (GVL) activity after T cell depletion is conditioned by the donor CTLA-4 genotype.

Application of FISH 7q in MDS patients without monosomy 7 or 7q deletion by conventional G-banding cytogenetics: Does −7/7q− detection by FISH have prognostic value?

Chromosomal abnormalities are detected in 40-60% of patients with de novo myelodysplastic syndromes (MDS). This study used the FISH technique in 773 patients with de novo MDS without evidence of monosomy 7 (-7) or 7q deletion (7q-) by conventional G-banding cytogenetics (CC) to analyze their prognostic impact by FISH alone. FISH detected -7/7q- in 5.2% of patients. Presence of -7/7q- was associated with shorter overall survival than absence of such aberrations. Our results suggest that FISH 7q could be beneficial in patients with intermediate WHO morphologic risk stratification and no evidence of -7/7q- by CC.

Chronic lymphocytic leukemia cells in lymph nodes show frequent NOTCH1 activation.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western world. Pathogenic mechanisms involve multiple external events (such as microenvironmental and antigenic stimuli) and internal events (genetic and epigenetic alterations) that are associated with the transformation,

Early peripheral blood and T-cell chimerism dynamics after umbilical cord blood transplantation supported with haploidentical cells

Single-unit umbilical cord blood (CB) SCT is limited by low total nucleated cell (TNC) dose. Co-infusion of CD34+ cells from a third party HLA-mismatched donor, known as dual or haplo-cord transplant, reduces the period of post-transplant neutropenia and related complications. The aim of this study was to analyze the value of early post-transplant peripheral blood (PB) and T cell chimerism after 28 dual transplants regarding CB engraftment. Cumulative incidence of myeloid engraftment at 30 days was 93% with a median time to engraftment of 14 days (10–29). Patients who developed CB graft failure (n=5) showed very low percentages of CB cells on days +14, +21 and +28 with decreasing dynamics. On the other hand, percentages of CB cells in patients who achieved CB engraftment increased over time. Interestingly, such patients showed two distinct chimerism dynamics in PB, but all of them showed a predominance of CB T cells early after SCT with increasing dynamics over time. Early post-transplant chimerism dynamics in PB and T cells predicts CB graft failure enabling rapid therapeutic measures to be applied. On the other hand, early increasing percentages of CB T cells correlates with ultimate CB engraftment.

Mutation of the NPM1 gene contributes to the development of donor cell–derived acute myeloid leukemia after unrelated cord blood transplantation for acute lymphoblastic leukemia

Donor cell leukemia (DCL) is a rare but severe complication after allogeneic stem cell transplantation. Its true incidence is unknown because of a lack of correct recognition and reporting, although improvements in molecular analysis of donor-host chimerism are contributing to a better diagnosis of this complication. The mechanisms of leukemogenesis are unclear, and multiple factors can contribute to the development of DCL. In recent years, cord blood has emerged as an alternative source of hematopoietic progenitor cells, and at least 12 cases of DCL have been reported after unrelated cord blood transplantation. We report a new case of DCL after unrelated cord blood transplantation in a 44-year-old woman diagnosed as having acute lymphoblastic leukemia with t(1;19) that developed acute myeloid leukemia with normal karyotype and nucleophosmin (NPM1) mutation in donor cells. To our knowledge, this is the first report of NPM1 mutation contributing to DCL development.

Karyotypic complexity rather than chromosome 8 abnormalities aggravates the outcome of chronic lymphocytic leukemia patients with TP53 aberrations

Patients with chronic lymphocytic leukemia (CLL) harboring TP53 aberrations (TP53abs; chromosome 17p deletion and/or TP53 mutation) exhibit an unfavorable clinical outcome. Chromosome 8 abnormalities, namely losses of 8p (8p−) and gains of 8q (8q+) have been suggested to aggravate the outcome of patients with TP53abs. However, the reported series were small, thus hindering definitive conclusions. To gain insight into this issue, we assessed a series of 101 CLL patients harboring TP53 disruption. The frequency of 8p− and 8q+ was 14.7% and 17.8% respectively. Both were associated with a significantly (P < 0.05) higher incidence of a complex karyotype (CK, ≥3 abnormalities) detected by chromosome banding analysis (CBA) compared to cases with normal 8p (N-8p) and 8q (N-8q), respectively. In univariate analysis for 10-year overall survival (OS), 8p− (P = 0.002), 8q+ (P = 0.012) and CK (P = 0.009) were associated with shorter OS. However, in multivariate analysis only CK (HR = 2.47, P = 0.027) maintained independent significance, being associated with a dismal outcome regardless of chromosome 8 abnormalities. In conclusion, our results highlight the association of chromosome 8 abnormalities with CK amongst CLL patients with TP53abs, while also revealing that CK can further aggravate the prognosis of this aggressive subgroup.

Inhibitory killer cell immunoglobulin-like receptor (iKIR) mismatches improve survival after T-cell-repleted haploidentical transplantation

Alloreactivity triggered by interaction between killer cell immunoglobulin‐like receptors (KIRs) and natural killer (NK) cells plays a role in the graft‐versus‐tumor effect after hematopoietic stem cell transplantation (SCT). Our aim in this study was to evaluate this role in the setting of T‐cell‐repleted haploidentical SCT with postinfusion high‐dose cyclophosphamide (PT‐Cy). We included 33 patients. Among patient–donor pairs with at least 1 inhibitory KIR (iKIR) gene mismatch, event‐free survival (EFS) and cumulative incidence of relapse 1 year after transplant were significantly better (85% vs. 37% [P = 0.008] and 18% vs. 46% [P = 0.041], respectively). A subanalysis in 12 patients with Hodgkins lymphoma (HL) showed an improvement in EFS 1 year after transplant in those patients with KIR ligand mismatch (100% vs. 25%, P = 0.012), although overall survival (OS) was not affected (85% vs. 80%, P = 0.2). Eight of 12 patient–donors pairs presented iKIR mismatches. Of note, this outcome was better in the small subgroup, both for EFS (100% vs. 25%, P = 0.012) and for OS (100% vs. 37%, P = 0.004). Our data suggest that in the setting of T‐cell‐repleted haploidentical SCT with PT‐Cy, iKIR mismatch is associated with improved survival, with particularly good results for both iKIR and KIR ligand mismatches in patients with HL.

The Genotype of the Donor for the (GT)n Polymorphism in the Promoter/Enhancer of FOXP3 Is Associated with the Development of Severe Acute GVHD but Does Not Affect the GVL Effect after Myeloablative HLA-Identical Allogeneic Stem Cell Transplantation

The FOXP3 gene encodes for a protein (Foxp3) involved in the development and functional activity of regulatory T cells (CD4+/CD25+/Foxp3+), which exert regulatory and suppressive roles over the immune system. After allogeneic stem cell transplantation, regulatory T cells are known to mitigate graft versus host disease while probably maintaining a graft versus leukemia effect. Short alleles (≤(GT)15) for the (GT)n polymorphism in the promoter/enhancer of FOXP3 are associated with a higher expression of FOXP3, and hypothetically with an increase of regulatory T cell activity. This polymorphism has been related to the development of auto- or alloimmune conditions including type 1 diabetes or graft rejection in renal transplant recipients. However, its impact in the allo-transplant setting has not been analyzed. In the present study, which includes 252 myeloablative HLA-identical allo-transplants, multivariate analysis revealed a lower incidence of grade III-IV acute graft versus host disease (GVHD) in patients transplanted from donors harboring short alleles (OR = 0.26, CI 0.08–0.82, p = 0.021); without affecting chronic GVHD or graft versus leukemia effect, since cumulative incidence of relapse, event free survival and overall survival rates are similar in both groups of patients.

A variant in IRF3 impacts on the clinical outcome of AML patients submitted to Allo-SCT

Allo-SCT has a strong curative potential for AML patients mainly due to a GVL effect. Unfortunately, GvL and GVHD are intimately linked. IFN regulatory factor-3 (IRF3), by modulating innate immune reactions, could impact on the incidence and intensity of GVL and GVHD. We analyzed two gene variants in IRF3 (rs7251 and rs2304205) on the clinical outcome of 249 AML patients submitted to HLA-identical sibling allo-SCT. Patients with a donor carrying the dominant GG gene variant in rs7251 had, as compared with GC and CC variants, a lower acute GVHD (aGVHD) III–IV incidence (4% vs 11% vs 27%; P=0.0078), a higher relapse incidence (49% vs 35% vs 26%; P=0.018), and lower TRM (7% vs 24% vs 18%; P=0.0065). In functional studies, the GG variant was associated with lower production of IFN-γ, decreased lymphocyte proliferation after antigen presentation by DCs, and lower cytotoxic response of mature natural killer cells. Patients carrying the AA dominant variant in rs2304205 had higher relapse incidence (50% vs 39% vs 18%, P=0.0068). The presence of both variants (GG in rs7251 and AA in rs2304205) in donors and patients resulted in a stronger clinical impact.