The putative anti-leukemic effects of anti-thymocyte globulins in patients with CD7-positive acute myeloid leukemia

CD7-positive leukemic blasts with DNMT3A mutations predict poor prognosis in patients with acute myeloid leukemia

Background

DNMT3A mutations can be detected in premalignant hematopoietic stem cells and are primarily associated with clonal hematopoiesis of indeterminate potential; however, current evidence does not support assigning them to a distinct European Leukemia Net (ELN) prognostic risk stratification. CD7 is a lymphoid antigen expressed on blasts in approximately 30% of acute myeloid leukemia (AML), and its role in AML remains unclear and depends on subgroup evaluation. This study investigated the prognostic value of DNMT3A mutation combined with CD7 expression in AML.

Methods

We retrospectively analyzed the clinical data of 297 newly diagnosed non-M3 AML patients. According to the DNMT3A mutation and CD7 expression in AML cells, patients were divided into the DNMT3A-mutated/CD7-positive (CD7+), DNMT3A-mutated/CD7-negative (CD7-), DNMT3A-wild-type/CD7+, and DNMT3A-wild-type/CD7- groups.

Results

The DNMT3A-mutated/CD7+ group had lower complete remission rates and higher relapse rates. Importantly, these patients had significantly shorter overall survival (OS) and relapse-free survival (RFS). Furthermore, multivariate analysis showed that CD7+ with DNMT3A mutation was an independent risk factor for OS and RFS.

Conclusion

CD7+ with DNMT3A mutation predicts a poor prognosis in AML patients, and the immunophenotype combined with molecular genetic markers can help to further refine the current risk stratification of AML.

Prognostic value of lymphoid marker CD7 expression in acute myeloid leukemia patients undergoing allogeneic hematopoietic cell transplantation in first morphological complete remission

Although defined as a lymphoid surface marker, CD7 is aberrantly expressed on a subtype of acute myeloid leukemia cells and appears to be associated with an inferior response to chemotherapy. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative modality but no data has been reported in CD7-positive AML patients. We performed a retrospective analysis involving 141 AML patients who underwent allo-HCT in first morphological complete remission (CR1). The results showed that CD7-positive AML patients had a poor 2-year overall survival (64.5% vs 82.0%, P = 0.040), relapse-free survival (RFS) (56.5% vs 79.4%, P = 0.005), and higher cumulative incidence of relapse (27.0% vs 9.7%, P = 0.003) post-HCT. In addition, expression of CD7 was related to RAS and RUNX1 mutation, and high residual disease level pre-HCT. Multivariate analyses showed CD7 expression at diagnosis was an independent risk factor for RFS (P = 0.016, HR = 0.418) and relapse (P = 0.014, HR = 0.307). We concluded that for AML patients in CR1, CD7 is a negative predictor for allo-transplant outcomes.

Hematopoietic cell transplant outcomes after myeloablative conditioning with fludarabine, busulfan, low-dose total body irradiation, and rabbit antithymocyte globulin

Optimal conditioning and graft-vs-host disease (GVHD) prophylaxis for hematopoietic cell transplantation (HCT) are unknown. Here, we report on outcomes after low toxicity, myeloablative conditioning consisting of fludarabine, busulfan, and 4 Gy total body irradiation, in combination with thymoglobulin and post-transplant methotrexate and cyclosporine. We retrospectively studied 700 patients with hematologic malignancies who received blood stem cells from 7 to 8/8 HLA-matched unrelated or related donors. Median follow-up of surviving patients was 5 years. At 5 years, overall survival (OS), relapse-free survival (RFS), and chronic GVHD/relapse-free survival (cGRFS) were 58%, 55%, and 40%. Risk factors for poor OS, RFS, and cGRFS were (1). high to very high disease risk index (DRI), (2). high recipient age, and (3). cytomegalovirus (CMV)-seropositive recipient with seronegative donor (D-R+). The latter risk factor applied particularly to patients with lymphoid malignancies. Neither donor other than HLA-matched sibling (7-8/8 unrelated) nor one HLA allele mismatch was risk factors for poor OS, RFS, or cGRFS. In conclusion, the above regimen results in excellent long-term outcomes. The outcomes are negatively impacted by older age, high or very high DRI, and CMV D-R+ serostatus, but not by donor unrelatedness or one HLA allele mismatch.

[CD7 expression and its prognostic significance in acute myeloid leukemia patients with wild-type or mutant CEBPA]

目的

分析CD7在初治急性髓系白血病（AML）患者中的表达和预后价值，进一步探讨CD7表达情况与CEBPA突变的相关性，明确其在CEBPA野生型和突变型AML患者中与预后的关系。

方法

回顾性分析2010年1月至2016年12月收治的298例初治AML患者（除外M₃亚型）的临床资料，在全部患者以及CEBPA野生型和突变型组中，分别比较CD7阳性（CD7⁺）和CD7阴性（CD7⁻）患者的临床特征及预后差异，并联合CD7表达情况和CEBPA突变状态初步建立新的危险分层模型。

结果

在CD7⁺组中，CEBPA单位点和双位点突变的发生率分别为10.1%和33.9%，显著高于CD7⁻组（5.3%和4.2%），差异具有统计学意义（P=0.000）。在CEBPA野生型患者中，CD7⁺组患者相较CD7⁻组患者完全缓解率低（P=0.001）、复发率高（P=0.023），而两组总生存（OS）期和无病生存（DFS）期差异无统计学意义（P值均>0.05）；在CEBPA突变患者中，CD7⁺组显示有更长的OS期（P=0.019）和DFS期（P=0.010）。根据CD7表达和CEBPA突变与否将AML患者分为三个亚组：CD7⁺伴CEBPA突变组、CD7⁻组和CD7⁺伴CEBPA野生型组。三组患者的3年OS率分别为80.2%、48.0%和30.6%（P<0.001），3年的DFS率分别为74.1%、37.4%和22.2%（P<0.001）。

结论

CD7⁺组中CEBPA突变率显著高于CD7⁻组，CD7⁺在CEBPA野生型组和突变组AML中存在截然相反的预后意义。根据CD7表达情况和CEBPA突变与否建立新的危险分层模型，有助于指导临床个体化治疗。

Personalizing rabbit anti-thymocyte globulin therapy for prevention of graft-versus-host disease after allogeneic hematopoietic cell transplantation: is there an optimal dose?

The efficacy of anti-thymocyte globulin (ATG) as prophylaxis for graft-versus-host disease (GVHD) has been investigated by many clinical studies over the past decade, including some randomized controlled trials. Intriguingly, although ATG is commonly used as prophylaxis for GVHD, there is still controversy about the optimal dose of ATG for prophylaxis of GVHD after allogeneic hematopoietic cell transplantation (allo-HCT). Indeed, the dose and formulation of ATG, as well as the degree of clinical benefit, has varied among studies, which makes it difficult to fully determine the clinical benefit of ATG. The aim of this review is to summarize the information regarding the optimal ATG dose of each formulation according to stem cell source, and to discuss how best to determine the personalized optimal dose of ATG in each allo-HCT recipient.