In vivo administration of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor increases neutrophil oxidative burst activity

Immune reconstitution post allogeneic transplant and the impact of immune recovery on the risk of infection

Infection is the leading cause of non-relapse mortality after allogeneic haematopoietic cell transplantation (HCT). This occurs as a result of dysfunction to the host immune system from the preparative regimen used prior to HCT, combined with a delay in reconstitution of the donor-derived immune system after HCT. In this article, we elaborate on the process of immune reconstitution post-HCT that begins with the innate system and is followed by recovery of adaptive immunity. Simultaneously, we describe how the tempo of immune reconstitution influences the risk of various infections. We explain some of the key differences in immune reconstitution and the consequent risk of infections in recipients of peripheral blood stem cell, bone marrow or umbilical cord blood grafts. Other factors that impact on immune recovery are also highlighted. Finally, we allude to various strategies that are being tested to enhance immune reconstitution post-HCT.

Evaluation of Tumor Necrosis Factor-Alpha and Granulocyte Colony-Stimulating Factor Serum Levels in Lead-Exposed Smoker Workers

Inorganic lead (Pb) is able to modulate the immune response even at low to moderate exposure levels. It inhibits in vitro and in vivo activities of neutrophil leucocytes and influences their blood count in humans. Neutrophil functions are governed by a number of cytokines. Pb has been shown to affect leukocyte production of some of these cytokines in vitro. The objective of this study is to assess serum tumor necrosis factor-alpha (TNF-α) and granulocyte colony-stimulating factor (G-CSF) levels of thirty-three male lead-exposed (E) workers at a lead recycling plant as compared with twenty-eight male non-exposed (NE) workers at a food processing plant, whose current smoking habit was known. Serum TNF-α and G-CSF levels were measured by a quantitative sandwich enzyme immunoassay. Blood lead levels (Pb-B) were significantly higher in E (geometric mean (GM) 30.7 μg/dl, GSD 1.7; min-max: 9.1–81.6 μg/dl) workers than controls (GM 3.6 μg/dl, GSD 1.7; min-max: 1.0–11.0 μg/dl). E workers had significantly higher serum TNF-α (median: 107.1; min-max: 11.1–623.0 pg/ml) and G-CSF levels (median: 53.0, min-max: 31.1–197.0 pg/ml) than NE workers (TNF-α: median: 12.0; min-max: 9.4–18.8 pg/ml; G-CSF: median: 34.3, min-max: 25.1–52.2 pg/ml). In particular, the TNF-α level was shown to be significantly influenced by lead exposure and smoking habit, as well as by interaction between these two factors. Both serum TNF-α and G-CSF levels were correlated with Pb-B and absolute neutrophil count. This study is the first to detect higher serum levels of G-CSF in E over NE workers. Our data confirm that exposure to low to medium doses of lead may interfere in the complex cytokine network involved in inflammation, especially in workers who are current smokers.

Defective pulmonary innate immune responses post-stem cell transplantation; review and results from one model system

Infectious pulmonary complications limit the success of hematopoietic stem cell transplantation (HSCT) as a therapy for malignant and non-malignant disorders. Susceptibility to pathogens in both autologous and allogeneic HSCT recipients persists despite successful immune reconstitution. As studying the causal effects of these immune defects in the human population can be limiting, a bone marrow transplant (BMT) mouse model can be used to understand the defect in mounting a productive innate immune response post-transplantation. When syngeneic BMT is performed, this system allows the study of BMT-induced alterations in innate immune cell function that are independent of the confounding effects of immunosuppressive therapy and graft-versus-host disease. Studies from several laboratories, including our own show that pulmonary susceptibility to bacterial infections post-BMT are largely due to alterations in the lung alveolar macrophages. Changes in these cells post-BMT include cytokine and eicosanoid dysregulations, scavenger receptor alterations, changes in micro RNA profiles, and alterations in intracellular signaling molecules that limit bacterial phagocytosis and killing. The changes that occur highlight mechanisms that promote susceptibility to infections commonly afflicting HSCT recipients and provide insight into therapeutic targets that may improve patient outcomes post-HSCT.

Immune response of severely injured patients--influence of surgical intervention and therapeutic impact

BACKGROUND

[corrected] Severe injury leads to a severe deterioration of the patients' immune response. The changes of the immune response after severe injury include a broad range of immune functions and may result in a status of immunosuppression, which could favor infectious complications. Therefore, immunostimulating therapies have been introduced in the therapy for severely injured patients in clinical and experimental settings.

OBJECTIVES

The article summarizes actual immunomodulating approaches in the treatment of trauma patients and therapeutic strategies avoiding additional immune deteriorations.

RESULTS

Examples for an immunostimulating approach in trauma patients are interferon gamma and the granulocyte macrophage-colony-stimulating factor (GM-CSF), which are summarized in this review in detail. However, the effect of such an interference in the patients' immune response with all its different cellular targets is not yet clearly understood, and most studies focus on the reaction of circulating monocytes. In addition, further immunomodulating strategies, including nutritional support, are addressed. However, clinically established therapeutic immunomodulating strategies in trauma care so far do not exist. The impact of the accidental and also an additional surgical trauma on the immune response has been clearly demonstrated. Therefore, the idea of a "damage control orthopedic surgery" (DCOS) is not only necessary to prevent further deterioration of the homeostasis of, e.g., the coagulating system, but is also desirable in terms of minimizing the burden on the immune system. In addition, also the timing of secondary surgical treatment in trauma patient care should include an evaluation of the immune response, although the most reliable markers still need to be identified.

CONCLUSION

Immunomodulating therapies in trauma patients exist on an experimental level with inconsistent results. The general management of trauma patients includes strategies that have been developed also on the basis of immunological considerations.

Neutrophil respiratory burst following liver transplantation: in vitro effects of granulocyte colony-stimulating factor

Early postoperative infections and septic complications are predominant causes of morbidity and mortality in patients following orthotopic liver transplantation (OLTx). Prophylactic granulocyte colony-stimulating factor (G-CSF) administration after OLTx was found to decrease the number of sepsis episodes and sepsis-related mortality. Since polymorphonuclear neutrophils (PMNs) are one of the major determinants of antimicrobial defense, alteration of their functions may influence the development of sepsis in these patients. Therefore, we investigated in vitro whether or not priming with G-CSF affects the neutrophils' respiratory burst (RB) in immunosuppressed liver-transplanted patients. Venous blood was drawn from liver allograft recipients (n=12) between the 5th and 15th day postoperatively. Patients without clinical signs of infection or rejection were included in this study. Leukocytes were obtained as supernatant following sedimentation and incubated with 1000 IE ml-1 G-CSF. The RB was measured by the intracellular oxidation of non-fluorescent dihydrorhodamine to the fluorescent rhodamine by flow cytometry. The results were expressed as a percentage of increasing stimulation compared to the control responses, which are made up of the percentage of cells with RB reaction after stimulation with phorbol ester (PMA), bacteria (E. coli), or the combination of a cytokine (TNF-alpha) and a bacterial peptide (FMLP) in the absence of G-CSF. In vitro priming with G-CSF resulted in significantly increased activity of the RB after PMA (from 71.7% to 85.6%) and TNF-alpha/FMLP (from 58.4% to 72.7%) stimulation. These data demonstrate that G-CSF in vitro augments the RB of PMNs, thereby suggesting a possible therapeutic role for G-CSF as immunomodulating agent during bacterial and fungal infections following OLTx.

G-CSF during Escherichia coli versus Staphylococcus aureus pneumonia in rats has fundamentally different and opposite effects

We investigated if bacteria type alters outcome with prophylactic granulocyte colony stimulating factor (G-CSF) therapy during pneumonia. Rats received G-CSF or placebo daily for 6 d and after the third dose were intrabronchially inoculated with either Escherichia coli or Staphylococcus aureus. Without G-CSF, E. coli and S. aureus produced similar (p = NS) mortality rates (36 versus 38%) and serial changes in mean circulating neutrophil counts (CNC), but differing mean (+/- SE) tumor necrosis factor (TNF) levels (E. coli, 259 +/- 104 versus S. aureus, 51 +/- 17 pg/ml, p = 0.01). G-CSF prior to bacteria increased mean CNC more than six times compared with placebo (p = 0.001). However, with G-CSF in the first 6 h after E. coli, there was a greater than 20-fold decrease in mean (+/- SE) CNC (x 10(3)/ mm3) to below placebo (0.5 +/- 0.1 versus 0.8 +/- 0.1), whereas with G-CSF after S. aureus, there was only a fivefold decrease in mean CNC and CNC were greater than placebo (1.8 +/- 0.2 versus 0.8 +/- 0.1) (E. coli versus S. aureus decrease in CNC with G-CSF, p = 0.001). With E. coli, G-CSF worsened oxygenation and increased bacteremia and mortality, whereas with S. aureus, G-CSF improved oxygenation and decreased bacteremia and mortality (G-CSF therapy, E. coli versus S. aureus, p = 0.03, 0.05, and 0.001, respectively). Thus, during S. aureus pneumonia with low TNF levels, G-CSF increased CNC and bacterial clearance, resulting in less pulmonary injury and decreased death. During E. coli pneumonia with high TNF levels, G-CSF paradoxically decreased CNC, resulting in impaired bacterial clearance and worsened pulmonary injury and death. Bacterial species and the associated inflammatory mediator response can alter outcome with prophylactic G-CSF therapy during pneumonia.

In vitro effects of recombinant human granulocyte-macrophage colony-stimulating factor (RhGM-CSF) on polymorphonuclear cell (PMN) and monocyte (MO) functional capacities in ovarian cancer patients versus human volunteers

Human polymorphonuclear cells (PMN) and monocytes (MO) from four ovarian cancer patients and seventeen normal donors were in vitro pretreated with different concentrations (25, 50 and 100 IU, respectively) of rhGM-CSF. Phagocytosis and killing of PMN and MO as well as PMN polarization were evaluated in cancer patients before treatment (T0) and at the end of each chemotherapeutic cycle (T1, T2, T3 and T4, respectively) in comparison with normal donors. RhGM-CSF did not affect phagocytosis and killing of PMN and MO. On the other hand, this cytokine was per se endowed with the capacity to enhance PMN polarization in both cancer patients (at T2 interval) and normal donors.