Generation of poikiloderma with neutropenia (PN) induced pluripotent stem cells (iPSCs)

Poikiloderma with neutropenia (PN, Clericuzio-type poikiloderma with neutropenia) is a rare autosomal recessive disorder caused by biallelic mutations in the USB1 gene (Alias C16orf57 and MPN1). To date, there have been only 37 reported cases worldwide of this disorder that presents with neutropenia, early onset poikiloderma, respiratory infections, palmo-plantar hyperkeratosis, and skeletal defects. Here we described the generation of human induced pluripotent stem cell lines (PN1 and PN2) from the peripheral blood of a 1-year-old patient using the dox-inducible STEMCCA vector. This patient presented with bacteremia, pneumonia, and neutropenia. Analysis of bone marrow demonstrated normal cellularity with trilineage hematopoiesis and neutropenia

The negative impact of Wnt signaling on megakaryocyte and primitive erythroid progenitors derived from human embryonic stem cells

AbstractThe Wnt gene family consists of structurally related genes encoding secreted signaling molecules that have been implicated in many developmental processes, including regulation of cell fate and patterning during embryogenesis. Previously, we found that Wnt signaling is required for primitive or yolk sac-derived-erythropoiesis using the murine embryonic stem cell (ESC) system. Here, we examine the effect of Wnt signaling on the formation of early hematopoietic progenitors derived from human ESCs. The first hematopoietic progenitor cells in the human ESC system express the pan-hematopoietic marker CD41 and the erythrocyte marker, glycophorin A or CD235. We have developed a novel serum-free, feeder-free, adherent differentiation system that can efficiently generate large numbers of CD41+CD235+ cells. We demonstrate that this cell population contains progenitors not just for primitive erythroid and megakaryocyte cells but for the myeloid lineage as well and term this population the primitive common myeloid progenitor (CMP). Treatment of mesoderm-specified cells with Wnt3a led to a loss of hematopoietic colony-forming ability while the inhibition of canonical Wnt signaling with DKK1 led to an increase in the number of primitive CMPs. Canonical Wnt signaling also inhibits the expansion and/or survival of primitive erythrocytes and megakaryocytes, but not myeloid cells, derived from this progenitor population. These findings are in contrast to the role of Wnt signaling during mouse ESC differentiation and demonstrate the importance of the human ESC system in studying species-specific differences in development

Targeting GM-CSF in COVID-19 Pneumonia: Rationale and Strategies.

COVID-19 is a clinical syndrome ranging from mild symptoms to severe pneumonia that often leads to respiratory failure, need for mechanical ventilation, and death. Most of the lung damage is driven by a surge in inflammatory cytokines [interleukin-6, interferon-γ, and granulocyte-monocyte stimulating factor (GM-CSF)]. Blunting this hyperinflammation with immunomodulation may lead to clinical improvement. GM-CSF is produced by many cells, including macrophages and T-cells. GM-CSF-derived signals are involved in differentiation of macrophages, including alveolar macrophages (AMs). In animal models of respiratory infections, the intranasal administration of GM-CSF increased the proliferation of AMs and improved outcomes. Increased levels of GM-CSF have been recently described in patients with COVID-19 compared to healthy controls. While GM-CSF might be beneficial in some circumstances as an appropriate response, in this case the inflammatory response is maladaptive by virtue of being later and disproportionate. The inhibition of GM-CSF signaling may be beneficial in improving the hyperinflammation-related lung damage in the most severe cases of COVID-19. This blockade can be achieved through antagonism of the GM-CSF receptor or the direct binding of circulating GM-CSF. Initial findings from patients with COVID-19 treated with a single intravenous dose of mavrilimumab, a monoclonal antibody binding GM-CSF receptor α, showed oxygenation improvement and shorter hospitalization. Prospective, randomized, placebo-controlled trials are ongoing. Anti-GM-CSF monoclonal antibodies, TJ003234 and gimsilumab, will be tested in clinical trials in patients with COVID-19, while lenzilumab received FDA approval for compassionate use. These trials will help inform whether blunting the inflammatory signaling provided by the GM-CSF axis in COVID-19 is beneficial

Randomized phase 3 trial of ruxolitinib for COVID-19-associated acute respiratory distress syndrome

Objectives: Evaluate the safety and efficacy of the Janus kinase (JAK)1/JAK2 inhibitor ruxolitinib in COVID-19-associated acute respiratory distress syndrome requiring mechanical ventilation. Design: Phase 3 randomized, double-blind, placebo-controlled trial Ruxolitinib in Participants With COVID-19-Associated Acute Respiratory Distress Syndrome Who Require Mechanical Ventilation (RUXCOVID-DEVENT; NCT04377620). Setting: Hospitals and community-based private or group practices in the United States (29 sites) and Russia (4 sites). Patients: Eligible patients were greater than or equal to 12 years old, hospitalized with severe acute respiratory syndrome coronavirus 2 infection, and mechanically ventilated with a Pao2/Fio2 of less than or equal to 300 mm Hg within 6 hours of randomization. Interventions: Patients were randomized 2:2:1 to receive twice-daily ruxolitinib 15 mg, ruxolitinib 5 mg, or placebo, each plus standard therapy. Measurements and main results: The primary endpoint, 28-day mortality, was tested for each ruxolitinib group versus placebo using a mixed-effects logistic regression model and one-tailed significance test (significance threshold: p \u3c 0.025); no type 1 error was allocated to secondary endpoints. Between May 24, 2020 and December 15, 2020, 211 patients (age range, 24-87 yr) were randomized (ruxolitinib 15/5 mg, n = 77/87; placebo, n = 47). Acute respiratory distress syndrome was categorized as severe in 27% of patients (58/211) at randomization; 90% (190/211) received concomitant steroids. Day-28 mortality was 51% (39/77; 95% CI, 39-62%) for ruxolitinib 15 mg, 53% (45/85; 95% CI, 42-64%) for ruxolitinib 5 mg, and 70% (33/47; 95% CI, 55-83%) for placebo. Neither ruxolitinib 15 mg (odds ratio, 0.46 [95% CI, 0.201-1.028]; one-sided p = 0.029) nor 5 mg (odds ratio, 0.42 [95% CI, 0.171-1.023]; one-sided p = 0.028) significantly reduced 28-day mortality versus placebo. Numerical improvements with ruxolitinib 15 mg versus placebo were observed in secondary outcomes including ventilator-, ICU-, and vasopressor-free days. Rates of overall and serious treatment-emergent adverse events were similar across treatments. Conclusions: The observed reduction in 28-day mortality rate between ruxolitinib and placebo in mechanically ventilated patients with COVID-19-associated acute respiratory distress syndrome was not statistically significant; however, the trial was underpowered owing to early termination

Additional file 1: Table S1. of Neutropenic sepsis is associated with distinct clinical and biological characteristics: a cohort study of severe sepsis

Characteristics of enzyme-linked immunosorbent assays for plasma proteins. Table S2. Patient characteristics by neutropenia status among patients with an immunocompromising condition. Table S3. Associations of neutropenia with acute respiratory distress syndrome risk, acute kidney injury risk, and mortality among patients with an immunocompromising condition. Table S4. Association of an immunocompromising condition with acute respiratory distress syndrome risk, acute kidney injury risk, and mortality. Table S5. Patient characteristics among subjects undergoing biomarker testing. Table S6. Plasma protein concentrations by neutropenia status among patients with an immunocompromising condition. Table S7. Plasma protein concentrations in patients with an immunocompromising condition versus without an immunocompromising condition. (DOCX 30 kb

Cxcr2 and Cxcl5 regulate the IL-17/G-CSF axis and neutrophil homeostasis in mice

Neutrophils are essential for maintaining innate immune surveillance under normal conditions, but also represent a major contributor to tissue damage during inflammation. Neutrophil homeostasis is therefore tightly regulated. Cxcr2 plays a critical role in neutrophil homeostasis, as Cxcr2–/– mice demonstrate mild neutrophilia and severe neutrophil hyperplasia in the bone marrow. The mechanisms underlying these phenotypes, however, are unclear. We report here that Cxcr2 on murine neutrophils inhibits the IL-17A/G-CSF axis that regulates neutrophil homeostasis. Furthermore, enterocyte-derived Cxcl5 in the gut regulates IL-17/G-CSF levels and contributes to Cxcr2-dependent neutrophil homeostasis. Conversely, G-CSF was required for Cxcl5-dependent regulation of neutrophil homeostasis, and inhibition of IL-17A reduced plasma G-CSF concentrations and marrow neutrophil numbers in both Cxcl5–/– and Cxcr2–/– mice. Cxcr2–/– mice constitutively expressed IL-17A and showed increased numbers of IL-17A–producing cells in the lung, terminal ileum, and spleen. Most IL-17–producing splenocytes were responsive to IL-1β plus IL-23 in vitro. Depletion of commensal microbes by antibiotic treatment in Cxcr2–/– mice markedly decreased IL-17A and G-CSF expression, neutrophilia, and marrow myeloid hyperplasia. These data suggest a critical role for Cxcr2, Cxcl5, and commensal bacteria in regulation of the IL-17/G-CSF axis and neutrophil homeostasis at mucosal sites and have implications for the development of treatments for pathologies resulting from either excessive or ineffective neutrophil responses

Mavrilimumab in patients with severe COVID-19 pneumonia and systemic hyperinflammation (MASH-COVID): an investigator initiated, multicentre, double-blind, randomised, placebo-controlled trial

In patients with COVID-19, granulocyte-macrophage colony stimulating factor (GM-CSF) might be a mediator of the hyperactive inflammatory response associated with respiratory failure and death. We aimed to evaluate whether mavrilimumab, a monoclonal antibody to the GM-CSF receptor, would improve outcomes in patients with COVID-19 pneumonia and systemic hyperinflammation