Is G-CSF Dangerous in COVID-19: Why Not Use GM-CSF?

Aggravated pneumonia and diabetes in SARS-CoV-2 infected diabetic mice

Multiple clinical and epidemiological studies have shown an interconnection between coronavirus disease 2019 (COVID-19) and diabetes, but experimental evidence is still lacking. Understanding the interplay between them is important because of the global health burden of COVID-19 and diabetes. We found that C57BL/6J mice were susceptible to the alpha strain of SARS-CoV-2. Moreover, diabetic C57BL/6J mice with leptin receptor gene deficiency (db/db mice) showed a higher viral load in the throat and lung and slower virus clearance in the throat after infection than C57BL/6J mice. Histological and multifactor analysis revealed more advanced pulmonary injury and serum inflammation in SARS-CoV-2 infected diabetic mice. Moreover, SARS-CoV-2 infected diabetic mice exhibited more severe insulin resistance and islet cell loss than uninfected diabetic mice. By RNA sequencing analysis, we found that diabetes may reduce the collagen level, suppress the immune response and aggravate inflammation in the lung after infection, which may account for the greater susceptibility of diabetic mice and their more severe lung damage after infection. In summary, we successfully established a SARS-CoV-2 infected diabetic mice model and demonstrated that diabetes and COVID-19 were risk factors for one another.

JAK-STAT signaling as an ARDS therapeutic target: Status and future trends

Acute respiratory distress syndrome (ARDS) is characterized by noncardiogenic pulmonary edema. It has a high mortality rate and lacks effective pharmacotherapy. With the outbreak of COVID-19 worldwide, the mortality of ARDS has increased correspondingly, which makes it urgent to find effective targets and strategies for the treatment of ARDS. Recent clinical trials of Janus kinase (JAK) inhibitors in treating COVID-19-induced ARDS have shown a positive outcome, which makes the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway a potential therapeutic target for treating ARDS. Here, we review the complex cause of ARDS, the molecular JAK/STAT pathway involved in ARDS pathology, and the progress that has been made in strategies targeting JAK/STAT to treat ARDS. Specifically, JAK/STAT signaling directly participates in the progression of ARDS or colludes with other pathways to aggravate ARDS. We summarize JAK and STAT inhibitors with ARDS treatment benefits, including inhibitors in clinical trials and preclinical studies and natural products, and discuss the side effects of the current JAK inhibitors to reveal future trends in the design of JAK inhibitors, which will help to develop effective treatment strategies for ARDS in the future.

Medical countermeasures for the hematopoietic-subsyndrome of acute radiation syndrome in space

More than 50 years after the Apollo missions ended, the National Aeronautical and Space Administration (NASA) and other international space agencies are preparing a return to the moon as a step towards deep space exploration. At doses ranging from a fraction of a Gray (Gy) to a few Gy, crew will be at risk for developing bone marrow failure associated with the hematopoietic subsyndrome of acute radiation syndrome (H-ARS) requiring pharmacological intervention to reduce risk to life and mission completion. Four medical countermeasures (MCM) in the colony stimulating factor class of drugs are now approved for treatment of myelosuppression associated with ARS. When taken in conjunction with antibiotics, fluids, antidiarrheals, antiemetics, antipyretics, and other treatments for symptomatic illness, the likelihood for recovery and mission completion can be greatly improved. The current review describes the performance and health risks of deep space flight, ionizing radiation exposure during crewed missions to the moon and Mars, and U.S. Food and Drug Administration (FDA)-approved medical interventions to treat ARS. With an expansion of human exploration missions beyond low Earth orbit (LEO), including near-term Lunar and future Mars missions, inclusion of MCMs to counteract ARS in the spaceflight kit will be critical for preserving crew health and performance.

Suppression of Aspergillus fumigatus Germination by Neutrophils Is Enhanced by Endothelial-Derived CSF3 Production

Infection with Aspergillus fumigatus can cause life-threatening diseases in immunocompromised patients with an unacceptable mortality rate. Angioinvasion is one of the features of severe invasive aspergillosis. Neutrophils are short-lived immune cells regulated by colony-stimulating factor 3 (CSF3) that play a key role in anti-fungal immune responses. To investigate the interactions between A. fumigatus and the host immune cells, such as neutrophils, we stimulated human umbilical vein endothelial cells (HUVECs) with the conidia of A. fumigatus, and co-cultured them with human neutrophils. Apoptosis and functions of neutrophils were analyzed. Our results showed that HUVECs upregulate the expression of CSF3, which could reduce the apoptosis of neutrophils while enhancing their functions. Lack of CSF3 was associated with enhanced apoptosis of neutrophils with impaired function. This work indicated that the CSF3 is required for neutrophil survival and function, at least in the early stages of A. fumigatus infection.

Concurrent Lymphoma and COVID-19: Diagnostic and Therapeutic Challenges of High-Grade Lymphoma and COVID-19

The coronavirus disease 2019 (COVID-19) global pandemic has put an unprecedented strain on cancer care. The initial months were marred by fears of immunocompromised patients becoming opportunistic hosts to this deadly virus. We present a case of newly diagnosed high-grade B-cell lymphoma in a patient with COVID-19 and discuss the diagnostic and therapeutic challenges posed.

A 76-year-old female presented with one month of progressive malaise, poor appetite, weight loss, and night sweats. A surveillance COVID-19 polymerase chain reaction (PCR) resulted positive. With strict isolation precautions, the daily focused physical examination masked several key findings including multifocal adenopathy. She developed hypoxic respiratory failure and progressive transaminitis and cytopenias. Image-guided, rather than excisional, biopsy revealed high-grade B-cell lymphoma. Superimposed COVID-19 infection presented multiple challenges, but she completed treatment and achieved remission. Suspicion for underlying malignancy was high. Institutional concerns included obtaining imaging studies and the gold standard excisional tissue biopsy while maintaining acceptable staff exposure. Fortunately, a lymph node core biopsy confirmed the histopathological diagnosis of high-grade B-cell lymphoma. The administration of chemoimmunotherapy (rituximab, cyclophosphamide, doxorubicin, dose-reduced vincristine, and prednisone (R-CHOP)) posed inherent risks, notably, worsening cytopenias and hepatotoxicity. The approach to treatment was further complicated as the interaction of high-grade lymphoma and COVID-19 remained unclear.

Medical teams have faced delays executing formerly routine diagnostic studies and formulating timely and appropriate treatment strategies. Careful consideration of risks and benefits must be weighed. A multidisciplinary approach is crucial to successfully treat patients. The relationship between COVID-19 and cancer treatment is yet to be established, and large sample-size studies are required.

G-CSF - A double edge sword in neutrophil mediated immunity

Neutrophils are vital for the innate immune system's control of pathogens and neutrophil deficiency can render the host susceptible to life-threatening infections. Neutrophil responses must also be tightly regulated because excessive production, recruitment or activation of neutrophils can cause tissue damage in both acute and chronic inflammatory diseases. Granulocyte colony stimulating factor (G-CSF) is a key regulator of neutrophil biology, from production, differentiation, and release of neutrophil precursors in the bone marrow (BM) to modulating the function of mature neutrophils outside of the BM, particularly at sites of inflammation. G-CSF acts by binding to its cognate cell surface receptor on target cells, causing the activation of intracellular signalling pathways mediating the proliferation, differentiation, function, and survival of cells in the neutrophil lineage. Studies in humans and mice demonstrate that G-CSF contributes to protecting the host against infection, but conversely, it can play a deleterious role in inflammatory diseases. As such, neutrophils and the G-CSF pathway may provide novel therapeutic targets. This review will focus on understanding the role G-CSF plays in the balance between effective neutrophil mediated host defence versus neutrophil-mediated inflammation and tissue damage in various inflammatory and infectious diseases.

A Multicenter Analysis of the Outcome of Cancer Patients with Neutropenia and COVID-19 Optionally Treated with Granulocyte-Colony Stimulating Factor (G-CSF): A Comparative Analysis

BACKGROUND

Approximately 15% of patients infected by SARS-CoV-2 develop a distress syndrome secondary to a host hyperinflammatory response induced by a cytokine storm. Myelosuppression is associated with a higher risk of infections and mortality. There are data to support methods of management for neutropenia and COVID-19. We present a multicenter experience during the first COVID-19 outbreak in neutropenic cancer patients infected by SARS-CoV-2.

METHODS

Clinical retrospective data were collected from neutropenic cancer patients with COVID-19. Comorbidities, tumor type, stage, treatment, neutropenia severity, G-CSF, COVID-19 parameters, and mortality were analyzed. A bivariate analysis of the impact on mortality was carried out. Additionally, we performed a multivariable logistic regression to predict respiratory failure and death.

RESULTS

Among the 943 cancer patients screened, 83 patients (11.3%) simultaneously had neutropenia and an infection with COVID-19. The lungs (26%) and breasts (22%) were the primary locations affected, and most patients had advanced disease (67%). In the logistic model, as adjusted covariates, sex, age, treatment (palliative vs. curative), tumor type, and the lowest level of neutrophils were used. A significant effect was obtained for the number of days of G-CSF treatment (OR = 1.4, 95% CI [1,1,03,92], p-value = 0.01).

CONCLUSIONS

Our findings suggest that a prolonged G-CSF treatment could be disadvantageous for these cancer patients with infections by COVID-19, with a higher probability of worse outcome.

Neutrophils at the crossroads of acute viral infections and severity

Neutrophils are versatile immune effector cells essential for mounting a first-line defense against invading pathogens. However, uncontrolled activation can lead to severe life-threatening complications. Neutrophils exist as a heterogeneous population, and their interaction with pathogens and other immune cells may shape the outcome of the host immune response. Diverse classes of viruses, including the recently identified novel SARS-CoV-2, have shown to alter the various aspects of neutrophil biology, offering possibilities for selective intervention. Here, we review heterogeneity within the neutrophil population, highlighting the functional consequences of circulating phenotypes and their critical involvement in exaggerating protective and pathological immune responses against the viruses. We discuss the recent findings of neutrophil extracellular traps (NETs) in COVID-19 pathology and cover other viruses, where neutrophil biology and NETs are crucial for developing disease severity. In the end, we have also pointed out the areas where neutrophil-mediated responses can be finely tuned to outline opportunities for therapeutic manipulation in controlling inflammation against viral infection.