AKT2 inhibition accelerates the acquisition of phagocytic ability in induced pluripotent stem cell-derived neutrophils.

Neutrophils are key components of the immune system that inhibit bacterial infections. Systemic bacterial infections can cause lethal conditions, especially in patients with neutropenia associated with chemotherapy or other systemic illnesses; hence, early detection of the symptoms and prompt management are crucial in such cases. Previously, we established expandable engineered neutrophil-primed progenitors (NeuPs-XL) using human-induced pluripotent stem cells (iPSCs), which can produce neutrophil-like cells at a clinically suitable scale within 4 days of inducing myeloid differentiation. In this study, using small-molecule compound-based screening, we detected that MK-2206, a selective pan-AKT inhibitor, can accelerate this differentiation process, promote phagocytic ability in neutrophils, and enhance cytokine and chemokine expression in response to lipopolysaccharides. The inhibition of AKT2 has been identified as the key mechanism underlying this acceleration. These results can make a substantial contribution to the development of strategies for the prompt production of clinically applicable iPSC-derived neutrophils, which can potentially lead to the management of severe infections associated with life-threatening neutropenia and the effective treatment of related health conditions in the future.

EVI1 exerts distinct roles in AML via ERG and cyclin D1 promoting a chemoresistant and immune-suppressive environment.

Aberrant expression of ecotropic viral integration site-1 (EVI1+) is associated with very poor outcomes in acute myeloid leukemia (AML), mechanisms of which are only partially understood. Using the green fluorescent protein reporter system to monitor EVI1 promoter activity, we demonstrated that Evi1high KMT2A-MLLT1-transformed AML cells possess distinct features from Evi1low cells: the potential for aggressive disease independent of stem cell activity and resistance to cytotoxic chemotherapy, along with the consistent gene expression profiles. RNA sequencing and chromatin immunoprecipitation sequencing in EVI1-transformed AML cells and normal hematopoietic cells combined with functional screening by cell proliferation-related short hairpin RNAs revealed that the erythroblast transformation-specific transcription factor ERG (E26 transformation-specific [ETS]-related gene) and cyclin D1 were downstream targets and therapeutic vulnerabilities of EVI1+ AML. Silencing Erg in murine EVI1+ AML models severely impaired cell proliferation, chemoresistance, and leukemogenic capacity. Cyclin D1 is also requisite for efficient EVI1-AML development, associated with gene expression profiles related to chemokine production and interferon signature, and T- and natural killer-cell exhaustion phenotype, depending on the interferon gamma (IFN-γ)/STAT1 pathway but not on CDK4/CDK6. Inhibiting the IFN-γ/STAT1 pathway alleviated immune exhaustion and impaired EVI1-AML development. Overexpression of EVI1 and cyclin D1 was associated with IFN-γ signature and increased expression of chemokines, with increased exhaustion molecules in T cells also in human AML data sets. These data collectively suggest that ERG and cyclin D1 play pivotal roles in the biology of EVI1+ AML, where ERG contributes to aggressive disease nature and chemoresistance, and cyclin D1 leads to IFN-γ signature and exhausted T-cell phenotypes, which could potentially be targeted.

A case of thymoma showing significant tumor reduction after anti-thymocyte globulin.

A 71-year-old female with type B3 thymoma developed severe aplastic anemia. Anti-thymocyte globulin was administered with glucocorticoids and cyclosporin A as the treatment for aplastic anemia. Computed tomography scan revealed that thymoma apparently shrank and remained without regrowth for at least 7 months. As previously reported, glucocorticoid has therapeutic effects on thymoma especially with abundant lymphocytes. Anti-thymocyte globulin also depletes peripheral lymphocytes, but its efficacy in the treatment of thymoma is unknown. Anti-thymocyte globulin and glucocorticoids may have cooperated with each other in reducing thymoma in our case. More cases should be accumulated to elucidate the effects of anti-thymocyte globulin on thymoma.

Efficient production of human neutrophils from iPSCs that prevent murine lethal infection with immune cell recruitment.

Neutrophils play an essential role in innate immune responses to bacterial and fungal infections, and loss of neutrophil function can increase the risk of acquiring lethal infections in clinical settings. Here, we show that engineered neutrophil-primed progenitors derived from human induced pluripotent stem cells can produce functional neutrophil-like cells at a clinically applicable scale that can act rapidly in vivo against lethal bacterial infections. Using 5 different mouse models, we systematically demonstrated that these neutrophil-like cells migrate to sites of inflammation and infection and increase survival against bacterial infection. In addition, we found that these human neutrophil-like cells can recruit murine immune cells. This system potentially provides a straight-forward solution for patients with neutrophil deficiency: an off-the-shelf neutrophil transfusion. This platform should facilitate the administration of human neutrophils for a broad spectrum of physiological and pathological conditions.

Fluoroquinolones for BK viral complication after transplantation: Meta-analysis.

OBJECTIVES: BK polyomavirus (BKV) causes two distinct complications after transplantation, hemorrhagic cystitis (BKV-HC) after hematopoietic stem cell transplantation (HSCT), and BKV-associated nephropathy (BKVAN) after kidney transplantation (KT). Although fluoroquinolones show efficacy against BKV proliferation in vitro, the clinical effect remains uncertain; thus, we performed meta-analysis to assess its efficacy in the prophylaxis. METHODS: Articles published before March 2020 were searched from PubMed, the Cochrane Library, ISRCTN registry, and ClinicalTrials.gov. Primary outcomes were BKV-HC after HSCT and BKVAN after KT. Secondary outcomes were BK viremia, viruria after KT, and fluoroquinolone-related adverse events. RESULTS: Three trials with 281 patients post-HSCT and 11 trials with 1882 patients post KT were included as for prophylaxis. Fluoroquinolone prophylaxis did not show effects on BKV-HC (OR 0.54, 95% CI 0.13-2.25), BKVAN (OR 0.74, 95% CI 0.35-1.55), and BK viremia (OR 0.79, 95% CI 0.49-1.28), but significantly decreased BK viruria (OR 0.64, 95% CI 0.45-0.91). Fluoroquinolone prophylaxis was associated with the higher percentage of fluoroquinolone-resistant infection among identified bacteria (OR 2.38, 95% CI 1.16-4.88), but the incidence of fluoroquinolone-resistant infection was similar (OR 1.15, 95% CI 0.71-1.86), due to the decrease of infection itself (OR 0.52, 95% CI 0.34-0.81). CONCLUSIONS: This meta-analysis showed that fluoroquinolones did not prevent BKV-HC after HSCT or BKVAN after KT, although the effect against BKV-HC should be further investigated by randomized controlled trials. Fluoroquinolones could reduce the rate of BK viruria to some extent but may not have clinically sufficient effects.

[Successful treatment of large granular lymphocytic leukemia accompanied by refractory anemia with alemtuzumab].

A 39-year-old man with anemia presented at our hospital in November 2011. Peripheral blood analysis revealed lymphocytosis with a large granular lymphocyte (LGL) count of 2,272/µl, with CD3+, CD4-, CD8+, CD56-, TCR-αß+; Southern blotting analysis revealed clonal TCR Cß 1 gene rearrangement, leading to the diagnosis of T-LGL leukemia. In June 2012, the patient was administered with cyclophosphamide as an initial treatment because he developed transfusion-dependent anemia. His anemia improved, and the treatment was discontinued in March 2013. However, anemia recurred in March 2014. The administration of cyclophosphamide was resumed; however, it was subsequently replaced with cyclosporine because of the risk of secondary cancer due to the long-term use of cyclophosphamide. However, his anemia did not improve. Further, the patient was administered with prednisone, methotrexate, and pentostatin; however, the transfusion-dependent state persisted with the cumulative transfusion of 186 RBC units until March 2016. After CD52 expression on the surface of LGL cells was confirmed, treatment with alemtuzumab, which is a monoclonal antibody against CD52, was initiated in April 2016 and the dose was gradually increased from 3 mg to 30 mg thrice per week. The patient's anemia began to improve 1 week after initiating alemtuzumab treatment, and he became transfusion-independent in the second week. Although alemtuzumab treatment was discontinued at the fifth week on the basis of a positive test result for CMV antigenemia, the result consequently became negative after ganciclovir treatment. To date, the patient's hemoglobin level has been maintained at approximately 12 g/dl without any treatment. Herein we reported the case of a patient having LGL leukemia with refractory anemia that was successfully treated using alemtuzumab.