Histamine dihydrochloride and low-dose interleukin-2 has antileukemic efficacy in NPM1-mutated and myelomonocytic/monocytic acute myeloid leukemia.

Not available.

Histamine targets myeloid-derived suppressor cells and improves the anti-tumor efficacy of PD-1/PD-L1 checkpoint blockade.

Myeloid-derived suppressor cells (MDSCs) are immature monocytes and granulocytes that impede immune-mediated clearance of malignant cells by multiple mechanisms, including the formation of immunosuppressive reactive oxygen species (ROS) via the myeloid cell NADPH oxidase (NOX2). Histamine dihydrochloride (HDC), a NOX2 inhibitor, exerts anti-cancer efficacy in experimental tumor models but the detailed mechanisms are insufficiently understood. To determine effects of HDC on the MDSC compartment we utilized three murine cancer models known to entail accumulation of MDSC, i.e. EL-4 lymphoma, MC-38 colorectal carcinoma, and 4T1 mammary carcinoma. In vivo treatment with HDC delayed EL-4 and 4T1 tumor growth and reduced the ROS formation by intratumoral MDSCs. HDC treatment of EL-4 bearing mice also reduced the accumulation of intratumoral MDSCs and reduced MDSC-induced suppression of T cells ex vivo. Experiments using GR1-depleted and Nox2 knock out mice supported that the anti-tumor efficacy of HDC required presence of NOX2+ GR1+ cells in vivo. In addition, treatment with HDC enhanced the anti-tumor efficacy of programmed cell death receptor 1 (PD-1) and PD-1 ligand checkpoint blockade in EL-4- and MC-38-bearing mice. Immunomodulatory effects of a HDC-containing regimen on MDSCs were further analyzed in a phase IV trial (Re:Mission Trial, ClinicalTrials.gov; NCT01347996) where patients with acute myeloid leukemia received HDC in conjunction with low-dose IL-2 (HDC/IL-2) for relapse prevention. Peripheral CD14+HLA-DR-/low MDSCs (M-MDSCs) were reduced during cycles of HDC/IL-2 therapy and a pronounced reduction of M-MDSCs during HDC/IL-2 treatment heralded favorable clinical outcome. We propose that anti-tumor properties of HDC may comprise the targeting of MDSCs.

Glucagon resistance in individuals with obesity and hepatic steatosis can be measured using the GLUSENTIC test and index.

Increased plasma levels of glucagon (hyperglucagonaemia) promote diabetes development but is also observed in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This may reflect hepatic glucagon resistance towards amino acid catabolism. A clinical test for measuring glucagon resistance has not been validated. We evaluated our glucagon sensitivity (GLUSENTIC) test, consisting of two study days: a glucagon injection and measurements of plasma amino acids, and an infusion of mixed amino acids and subsequent calculation of the GLUSENTIC index (primary outcome measure) from measurements of glucagon and amino acids. To distinguish glucagon-dependent from insulin-dependent actions on amino acid metabolism, we also studied patients with type 1 diabetes (T1D). The delta-decline in total amino acids was 49% lower in MASLD following exogenous glucagon (p=0.01), and the calculated GLUSENTIC index was 34% lower in MASLD (p<0.0001), but not T1D (p>0.99). In contrast, glucagon-induced glucose increments were similar in controls and MASLD (p=0.41). The GLUSENTIC test and index may be used to measure glucagon resistance in individuals with obesity and MASLD.

Development of a glucagon sensitivity test in humans: Pilot data and the GLUSENTIC study protocol.

A physiological feedback system exists between hepatocytes and the alpha cells, termed the liver-alpha cell axis and refers to the relationship between amino acid-stimulated glucagon secretion and glucagon-stimulated amino acid catabolism. Several reports indicate that non-alcoholic fatty liver disease (NAFLD) disrupts the liver-alpha cell axis, because of impaired glucagon receptor signaling (glucagon resistance). However, no experimental test exists to assess glucagon resistance in humans. The objective was to develop an experimental test to determine glucagon sensitivity with respect to amino acid and glucose metabolism in humans. The proposed glucagon sensitivity test (comprising two elements: 1) i.v. injection of 0.2 mg glucagon and 2) infusion of mixed amino acids 331 mg/hour/kg) is based on nine pilot studies which are presented. Calculation of a proposed glucagon sensitivity index with respect to amino acid catabolism is also described. Secondly, we describe a complete study protocol (GLUSENTIC) according to which the glucagon sensitivity test will be applied in a cross-sectional study currently taking place. 65 participants including 20 individuals with a BMI 18.6-25 kg/m2, 30 individuals with a BMI ≥ 25-40 kg/m2, and 15 individuals with type 1 diabetes with a BMI between 18.6 and 40 kg/m2 will be included. Participants will be grouped according to their degree of hepatic steatosis measured by whole-liver magnetic resonance imaging (MRI). The primary outcome measure will be differences in the glucagon sensitivity index between individuals with and without hepatic steatosis. Developing a glucagon sensitivity test and index may provide insight into the physiological and pathophysiological mechanism of glucagon action and glucagon-based therapies.

Isolated limb perfusion with melphalan activates interferon-stimulated genes to induce tumor regression in patients with melanoma in-transit metastasis.

Hyperthermic isolated limb perfusion (ILP) with high-dose melphalan is a treatment option for melanoma patients with metastasis confined to limbs (in-transit metastasis). The therapy entails a complete response (CR) rate of 50-70%. Cellular immunity is proposed to impact on the clinical efficacy of ILP, but the detailed aspects of ILP-induced immune activation remain to be explored. For this study, we explored the potential role of interferon-stimulated gene (ISG) products, including CXCL10, CCL2, PD-L2 and IFN-γ along with expression of their cognate receptors CXCR3, CCR4, CCR5 and PD-1 on lymphocytes, for the clinical efficacy of ILP. Patients with high serum levels of CXCL10, CCL2, PD-L2 and IFN-γ were more likely to achieve CR after ILP. Additionally, the expression of CXCR3, CCR4 and CCR5 on T cells and/or natural killer (NK) cells was enhanced by ILP. Peripheral blood mononuclear cells (PBMCs) secreted high levels of CXCL10, CCL2 and IFN-γ in response to co-culture with melphalan-exposed melanoma cells in vitro. Activated T cells migrated toward supernatants from these co-cultures. Furthermore, melphalan-exposed melanoma cells triggered upregulation of CXCR3, CCR4, CCR5 and PD-1 on co-cultured T cells and/or NK cells. Our results suggest that constituents released from melphalan-exposed melanoma cells stimulate the ISG axis with ensuing formation of chemokines and upregulation of chemokine receptor expression on anti-neoplastic immune cells, which may contribute in ILP-induced tumor regression.

Immunotherapy with HDC/IL-2 may be clinically efficacious in acute myeloid leukemia of normal karyotype.

Immunotherapy with histamine dihydrochloride and low-dose interleukin-2 (HDC/IL-2) reduces the risk of relapse in the post-chemotherapy phase of acute myeloid leukemia (AML). Here we report the results of exploratory analyses of the clinical efficacy of HDC/IL-2 in AML with focus on the impact of karyotype aberrations in leukemic cells. Post-hoc analyses of phase III trial data suggested that HDC/IL-2 is primarily beneficial for patients with AML of normal karyotype. These results may be helpful in the selection of patients who are suitable for therapy and in the design of future immunotherapy protocols aiming at further defining the mechanism of relapse prevention by HDC/IL-2.

IFNL4 Genotypes Predict Clearance of RNA Viruses in Rwandan Children With Upper Respiratory Tract Infections.

Polymorphisms in the interferon lambda gene locus (IFNL) such as the IFNL4 genetic variants rs12979860 and rs368234815 are predictive of resolution of hepatitis C virus infection, but information about the impact of these variants in other infections is scarce. This study aimed at determining the potential impact of IFNL4 variation for the clearance of respiratory tract pathogens in Rwandan children (≤5 years old, n = 480) seeking medical care for acute respiratory infections. Nasopharyngeal swabs were retrieved from all children at the first hospital referral and from 161 children at follow-up visits 2 weeks later. The swabs were analyzed for pathogens by real-time PCR and for host cell IFNL4 genotype at rs12979860 and rs368234815. Approximately 1/3 of the children were homozygous for the rs12979860 T allele and the rs368234815 ΔG allele, which are overrepresented in subjects of African descent. These IFNL4 variants were significantly associated with reduced clearance of RNA viruses. Our results suggest that IFNL4 genotypes that are common among subjects of African descent may determine inefficacious clearance of RNA viruses from the respiratory tract.

Anti-Leukemic Properties of Histamine in Monocytic Leukemia: The Role of NOX2.

In patients with acute myeloid leukemia (AML), treatment with histamine dihydrochloride (HDC) and low-dose IL-2 (HDC/IL-2) in the post-chemotherapy phase has been shown to reduce the incidence of leukemic relapse. The clinical benefit of HDC/IL-2 is pronounced in monocytic forms of AML, where the leukemic cells express histamine type 2 receptors (H2R) and the NAPDH oxidase-2 (NOX2). HDC ligates to H2Rs to inhibit NOX2-derived formation of reactive oxygen species, but details regarding the anti-leukemic actions of HDC remain to be elucidated. Here, we report that human NOX2+ myelomonocytic/monocytic AML cell lines showed increased expression of maturation markers along with reduced leukemic cell proliferation after exposure to HDC in vitro. These effects of HDC were absent in corresponding leukemic cells genetically depleted of NOX2 (NOX2-/-). We also observed that exposure to HDC altered the expression of genes involved in differentiation and cell cycle progression in AML cells and that these effects required the presence of NOX2. HDC promoted the differentiation also of primary monocytic, but not non-monocytic, AML cells in vitro. In a xenograft model, immunodeficient NOG mice were inoculated with wild-type or NOX2-/- human monocytic AML cells and treated with HDC in vivo. The administration of HDC reduced the in vivo expansion of NOX2+/+, but not of NOX2-/- human monocytic AML cells. We propose that NOX2 may be a conceivable target in the treatment of monocytic AML.

Cytomegalovirus Serostatus Affects Autoreactive NK Cells and Outcomes of IL2-Based Immunotherapy in Acute Myeloid Leukemia.

Human cytomegalovirus (CMV) infection is reported to promote NK cell differentiation and education. The CMV-induced generation of highly differentiated adaptive-like NK cells has been proposed to affect favorably on the maintenance of remission in patients with acute myeloid leukemia (AML) after allogeneic stem cell transplantation (allo-SCT). The impact of CMV infection and adaptive-like NK cells on relapse and survival of patients with AML not receiving allo-SCT remains unknown. We assayed CMV IgG serostatus to determine past CMV infection in 81 nontransplanted AML patients who were receiving relapse-prevention immunotherapy comprising histamine dihydrochloride and low-dose interleukin-2 (HDC/IL2; NCT01347996). CMV seropositivity correlated negatively with leukemia-free and overall survival of patients receiving HDC/IL2, but did not correlate with outcomes in a contemporary control cohort. Analysis of outcome after stratification of patients based on concordant or discordant killer immunoglobulin-like receptor (KIR) and HLA genotypes implied that the negative impact of CMV seropositivity was restricted to patients lacking a ligand to inhibitory KIRs (iKIR). Previous CMV infection was also associated with fewer NK cells expressing only nonself iKIRs (NS-iKIR). We propose that CMV-driven NK cell education depletes the population of NS-iKIR NK cells, which in turn reduces the clinical benefit of relapse-preventive immunotherapy in AML. Cancer Immunol Res; 6(9); 1110-9. ©2018 AACR.