Immunostimulation using granulocyte- and granulocyte-macrophage colony stimulating factor in patients with severe sepsis and septic shock

Cellular Markers of Immunosuppression in Sepsis

Sepsis is a pathological condition frequently caused by invasion of a pathogen and the subsequent unregulated response that threatens the patient's life through diverse organ failure. The incidence of sepsis is increasing, and there is no specific therapy. Despite technological contributions to treat sepsis or increased knowledge of its molecular pathophysiology, mortality remains high, and sepsis is a global health problem. Knowledge of the role of the cells involved in the host response through the synthesis of inflammatory mediators and their different effects on cells, tissues or systems is key to the development of medical treatments that regulate systems involved in such responses to pathogens. This review addresses new insights into the role of cells, their mediators, and the interaction between them that lead to the development of a state of immunosuppression.

The C-C Chemokine Receptor Type 4 Is an Immunomodulatory Target of Hydroxychloroquine

The emergence of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; COVID-19) in China, reported to the World Health Organization on December 31, 2019, has led to a large global pandemic and is a major public health issue. As a result, there are more than 200 clinical trials of COVID-19 treatments or vaccines that are either ongoing or recruiting patients. One potential therapy that has garnered international attention is hydroxychloroquine; a potent immunomodulatory agent FDA-approved for the treatment of numerous inflammatory and autoimmune conditions, including malaria, lupus, and rheumatoid arthritis. Hydroxychloroquine has demonstrated promise in vitro and is currently under investigation in clinical trials for the treatment of COVID-19. Despite an abundance of empirical data, the mechanism(s) involved in the immunomodulatory activity of hydroxychloroquine have not been characterized. Using the unbiased chemical similarity ensemble approach (SEA), we identified C-C chemokine receptor type 4 (CCR4) as an immunomodulatory target of hydroxychloroquine. The crystal structure of CCR4 was selected for molecular docking studies using the SwissDock modeling software. In silico, hydroxychloroquine interacts with Thr-189 within the CCR4 active site, presumably blocking endogenous ligand binding. However, the CCR4 antagonists compound 18a and K777 outperformed hydroxychloroquine in silico, demonstrating energetically favorable binding characteristics. Hydroxychloroquine may subject COVID-19 patients to QT-prolongation, increasing the risk of sudden cardiac death. The FDA-approved CCR4 antagonist mogalizumab is not known to increase the risk of QT prolongation and may serve as a viable alternative to hydroxychloroquine. Results from this report introduce additional FDA-approved drugs that warrant investigation for therapeutic use in the treatment of COVID-19.

Assessment of immune organ dysfunction in critical illness: utility of innate immune response markers

In critically ill patients, organ dysfunctions are routinely assessed, monitored, and treated. Mounting data show that substantial critical illness-induced changes in the immune system can be observed in most ICU patients and that not only "hyper-inflammation" but also persistence of an anti-inflammatory phenotype (as in sepsis-associated immunosuppression) is associated with increased morbidity and mortality. Despite common perception, changes in functional immunity cannot be adequately assessed by routine inflammatory biomarkers such as C-reactive protein, procalcitonin, or numerical analysis of leukocyte (sub)-counts. Cytokines appear also not suited due to their short half-life and pleiotropy, their unexclusive origin from immune cells, and their potential to undergo antagonization by circulating inactivating molecules. Thus, beyond leukocyte quantification and use of routine biomarkers, direct assessment of immune cell function seems required to characterize the immune systems' status. This may include determination of, e.g., ex vivo cellular cytokine release, phagocytosis activity, and/or antigen-presenting capacity. In this regard, standardized flow-cytometric assessment of the major histocompatibility-II complex human leukocyte antigen (-D related) (HLA-DR) has gained particular interest. Monocytic HLA-DR (mHLA-DR) controls the interplay between innate and adaptive immunity and may serve as a "global" biomarker of injury-associated immunosuppression, and its decreased expression is associated with adverse clinical outcomes (e.g., secondary infection risk, mortality). Importantly, recent data demonstrate that injury-associated immunosuppression can be reversed-opening up new therapeutic avenues in affected patients. Here we discuss the potential scientific and clinical value of assessment of functional immunity with a focus on monocytes/macrophages and review the current state of knowledge and potential perspectives for affected critically ill patients.

Dysfunction of respiratory muscles in critically ill patients on the intensive care unit

Muscular weakness and muscle wasting may often be observed in critically ill patients on intensive care units (ICUs) and may present as failure to wean from mechanical ventilation. Importantly, mounting data demonstrate that mechanical ventilation itself may induce progressive dysfunction of the main respiratory muscle, i.e. the diaphragm. The respective condition was termed 'ventilator-induced diaphragmatic dysfunction' (VIDD) and should be distinguished from peripheral muscular weakness as observed in 'ICU-acquired weakness (ICU-AW)'. Interestingly, VIDD and ICU-AW may often be observed in critically ill patients with, e.g. severe sepsis or septic shock, and recent data demonstrate that the pathophysiology of these conditions may overlap. VIDD may mainly be characterized on a histopathological level as disuse muscular atrophy, and data demonstrate increased proteolysis and decreased protein synthesis as important underlying pathomechanisms. However, atrophy alone does not explain the observed loss of muscular force. When, e.g. isolated muscle strips are examined and force is normalized for cross-sectional fibre area, the loss is disproportionally larger than would be expected by atrophy alone. Nevertheless, although the exact molecular pathways for the induction of proteolytic systems remain incompletely understood, data now suggest that VIDD may also be triggered by mechanisms including decreased diaphragmatic blood flow or increased oxidative stress. Here we provide a concise review on the available literature on respiratory muscle weakness and VIDD in the critically ill. Potential underlying pathomechanisms will be discussed before the background of current diagnostic options. Furthermore, we will elucidate and speculate on potential novel future therapeutic avenues.

Immunotherapy of Sepsis: Blind Alley or Call for Personalized Assessment?

Sepsis is the most frequent cause of death in noncoronary intensive care units. In the past 10 years, progress has been made in the early identification of septic patients and their treatment. These improvements in support and therapy mean that mortality is gradually decreasing, however, the rate of death from sepsis remains unacceptably high. Immunotherapy is not currently part of the routine treatment of sepsis. Despite experimental successes, the administration of agents to block the effect of sepsis mediators failed to show evidence for improved outcome in a multitude of clinical trials. The following survey summarizes the current knowledge and results of clinical trials on the immunotherapy of sepsis and describes the limitations of our knowledge of the pathogenesis of sepsis. Administration of immunomodulatory drugs should be linked to the current immune status assessed by both clinical and molecular patterns. Thus, a careful daily review of the patient's immune status needs to be introduced into routine clinical practice giving the opportunity for effective and tailored use of immunomodulatory therapy.

The immune response: targets for the treatment of severe sepsis

The clinical process of severe sepsis is characterized by extreme inflammation interlinked with potent stimulation of the coagulation cascade often followed by a state of relative immune paralysis. In this paper, we will review many of the potential therapies directed at various steps along the inflammatory cascade from modulation of inflammatory mediators eliciting the immune response, alteration of the host's immune response in both a stimulatory and depressive manner, and taming the overexuberant coagulation response triggered by the fierce coagulation-inflammation cycle. Finally, we will discuss further opportunities for research to improve our ability to design effective therapies.

In vivo effect of recombinant human granulocyte colony-stimulating factor on neutrophilic expression of CD11b in septic neonates: a randomized controlled trial

Neonates are susceptible to septicemia secondary to quantitative and qualitative neutrophilic defects. Granulocyte colony-stimulating factor (G-CSF) stimulates myeloid progenitor cell proliferation and induces selective neutrophil functions. The authors aimed to evaluate the effect of G-CSF administration in septic neonates on neutrophil production and CD11b expression. Sixty septic neonates were randomized to receive intravenous G-CSF 10 μg/kg/day for 3 days (G-CSF group, n = 30), or not to receive G-CSF (non-G-CSF group, n = 30). Thirty healthy newborns were included as controls. Laboratory investigations included complete blood count, C-reactive protein, blood culture, renal and liver function tests, and assessment of neutrophilic expression of CD11b. Total leukocytes count (TLC), absolute neutrophil count (ANC), and immature myeloid cell count in G-CSF group showed significant difference between post-and pre-G-CSF levels. TLC, ANC, immature myeloid cell count and immature/total myeloid cells ratio were higher in G-CSF group compared to non-G-CSF group on days 1 and 3. Higher neutrophilic expression of CD11b was reported in both septic groups on day 0 compared to control group. On day 5, CD11b was higher in G-CSF group than non-G-CSF group. G-CSF improved CD11b% in neutropenic and non-neutropenic septic neonates. No significant difference was found between pre- and posttreatment renal and liver function tests. Lower duration of antibiotic intake and hospitalization was observed in G-CSF group compared to non-G-CSF group. G-CSF administration as an adjuvant therapy for neonatal septicemia, whether neutropenic or not, improves neutrophilic count and function and contributed to early healing from sepsis.