Patients with stable uncomplicated cirrhosis have normal neutrophil function

Loss of Coordinated Neutrophil Responses to the Human Fungal Pathogen, Candida albicans, in Patients With Cirrhosis

Neutrophils are the most abundant white blood cell in the body and are key participants in the defense against fungal infections. Fungal infections occur often in patients with cirrhosis and are associated with increased 30-day and 90-day mortality. Previous studies have shown that specific neutrophil functions are abnormal in patients with cirrhosis, although the extent of neutrophil dysfunction is not well understood. We tested the ability of neutrophils from 21 hospitalized patients with cirrhosis and 23 healthy control patients to kill Candida albicans, a common fungal pathogen in patients with cirrhosis. Using an assay, we also measured the ability of neutrophils to coordinate multicellular, synchronized control of C. albicans hyphae through a process known as swarming. We found that neutrophils from patients with cirrhosis have significantly decreased fungicidal capacity compared with healthy control neutrophils (53% vs. 74%, P < 0.0001) and diminished ability to control hyphal growth normalized as a ratio to healthy control (0.22 vs. 0.65, P < 0.0001). Moreover, serum from patients with cirrhosis decreases the ability of healthy control neutrophils to kill C. albicans (from 60% to 41%, P < 0.003). Circulating concentration of the inflammatory cytokines tumor necrosis factor α, interleukin-6, and interleukin-8 were found to be significantly elevated in patients with cirrhosis compared to healthy controls. Following pretreatment with granulocyte-colony stimulating factor and granulocyte-macrophage colony-stimulating factor, neutrophil function was restored to almost that of healthy controls. Conclusion: Our data establish profound neutrophil dysfunction against, and altered swarming to, C. albicans in patients with cirrhosis. This dysfunction can be partially reversed with cytokine augmentation ex vivo.

Dysfunctional neutrophil effector organelle mobilization and microbicidal protein release in alcohol-related cirrhosis

Patients with alcohol-related cirrhosis (ALD) are prone to infection. Circulating neutrophils in ALD are dysfunctional and predict development of sepsis, organ dysfunction, and survival. Neutrophil granules are important effector organelles containing a toxic array of microbicidal proteins, whose controlled release is required to kill microorganisms while minimizing inflammation and damage to host tissue. We investigated the role of these granular responses in contributing to immune disarray in ALD. Neutrophil granular content and mobilization were measured by flow cytometric quantitation of cell-surface/intracellular markers, [secretory vesicles (CD11b), secondary granules (CD66b), and primary granules (CD63; myeloperoxidase)] before and after bacterial stimulation in 29 patients with ALD cirrhosis (15 abstinent; 14 actively drinking) compared with healthy controls (HC). ImageStream Flow Cytometry characterized localization of granule subsets within the intracellular and cell-surface compartments. The plasma cytokine environment was analyzed using ELISA/cytokine bead array. Circulating neutrophils were primed in the resting state with upregulated surface expression of CD11b (P = 0.0001) in a cytokine milieu rich in IL-8 (P < 0.001) and lactoferrin (P = 0.035). Neutrophils showed exaggerated mobilization to the cell surface of primary granules at baseline (P = 0.001) and in response to N-formyl-l-methionyl-l-leucyl-l-phenylalanine (P = 0.009) and Escherichia coli (P = 0.0003) in ALD. There was no deficit in granule content or mobilization to the cell membrane in any granule subset observed. Paradoxically, active alcohol consumption abrogated the hyperresponsive neutrophil granular responses compared with their abstinent counterparts. Neutrophils are preprimed at baseline with augmented effector organelle mobilization in response to bacterial stimulation; neutrophil degranulation is not a mechanism leading to innate immunoparesis in ALD.NEW & NOTEWORTHY Neutrophil granule release is dysregulated in patients with alcohol-related cirrhosis (ALD) with augmented effector organelle mobilization and microbiocidal protein release. Neutrophil granules are upregulated in ALD at baseline and demonstrate augmented responses to bacterial challenge. The granular responses in ALD did not contribute to the observed functional deficit in innate immunity but rather were dysregulated and hyperresponsive, which may induce bystander damage to host tissue. Paradoxically, active alcohol consumption abrogated the excessive neutrophil granular responses to bacterial stimulus compared with their abstinent counterparts.

Dysfunction of Circulating Polymorphonuclear Leukocytes and Monocytes in Ambulatory Cirrhotics Predicts Patient Outcome

BACKGROUND

Cirrhosis represents a state of functional immune paresis with increased infection risk.

AIMS

To investigate polymorphonuclear (PMN) leukocyte and monocyte function in ambulatory cirrhotics, and their potential relation with cirrhosis etiology or patient outcome.

METHODS

Consecutive ambulatory cirrhotics without current or recent (<1 month) infection or acute decompensation were prospectively enrolled in 2013 and followed for a median time of 20 months until death, transplant or end of 2014. Oxidative burst and phagocytosis of circulating PMNs and monocytes were investigated at baseline and after in vitro Escherichia coli stimulation. Seventeen healthy blood donors served as controls. Baseline clinical and laboratory data as well as follow-up data on the development of cirrhosis complications, including acute-on-chronic liver failure (ACLF), and bacterial infections were collected.

RESULTS

Sixty patients were included (70 % male, median age 63 years, 52 % with alcoholic cirrhosis). Compared to controls, cirrhotics showed increased resting and stimulated burst as well as reduced phagocytosis of PMNs, and increased stimulated monocyte burst (p < 0.05 for all). Alcoholic etiology was not related to PMN or monocyte dysfunction (p > 0.05 for all). In Cox regression analysis, increased stimulated monocyte and PMN burst were independent predictors of sepsis, severe sepsis and ACLF occurrence. Also, increased stimulated monocyte burst was associated with worse transplant-free survival (p < 0.05 for all).

CONCLUSIONS

Stimulated PMN and monocyte oxidative burst are increased in ambulatory cirrhotics without acute decompensation. In turn, these changes are associated to sepsis and ACLF occurrence.

Effect of long-term acid gastric inhibition on bacterial translocation in cirrhotic rats

BACKGROUND

Bacterial translocation (BT) related to intestinal bacterial overgrowth (IBO) plays an important role in the pathogenesis of bacterial infections in cirrhosis. Inhibition of acid gastric secretion promotes IBO and might favor BT. We evaluated the effect of long-term inhibition of acid gastric secretion on BT in cirrhotic rats.

METHODS

Cirrhotic rats with and without ascites induced by oral CCl4 and controls were randomized to treatment with a daily subcutaneous injection of placebo, ranitidine (50 mg/kg), or pantoprazole (8 mg/kg) during 2 weeks. Continuous pH-metry was performed for 2 h before and at the end of treatment; thereafter, a laparotomy to obtain samples of blood, mesenteric lymph nodes, ascites, spleen, liver, and cecal stools was performed.

RESULTS

Ranitidine and pantoprazole increased gastric pH as compared with placebo (P<0.001). However, antisecretory drugs increased the incidence of BT only in ascitic rats treated with ranitidine (P<0.05) or pantoprazole (P=0.07) when compared with placebo-treated ascitic rats or cirrhotic rats without ascites treated with the same drug. Cirrhotic ascitic rats treated with pantoprazole showed a trend toward an increased incidence of IBO (P=0.08), a higher ileal malondialdehyde level (P<0.01), and an increased production of tumor necrosis factor-α (P<0.05).

CONCLUSION

Although inhibition of acid gastric secretion increased gastric pH in all animals, the incidence of BT increased only in ascitic rats, and it was associated with a trend toward an increase in IBO incidence, a higher ileal malondialdehyde level, and an increased production of serum tumor necrosis factor-α. Therefore, antisecretory drugs should be carefully administered to cirrhotic ascitic patients.

The severity of circulating neutrophil dysfunction in patients with cirrhosis is associated with 90-day and 1-year mortality

BACKGROUND

Patients with cirrhosis are susceptible to sepsis, pre-disposing to the development of encephalopathy, bleeding and organ dysfunction with associated high mortality.

AIM

To characterise circulating neutrophil function in a cirrhotic cohort as a determinant of 90-day and 1-year mortality.

METHODS

Sixty-two patients with cirrhosis [49 stable (Child-Pugh A/B/C = 24%/39%/37%); 13 acute-on-chronic liver failure] were prospectively studied and compared with 11 healthy controls. Neutrophil function was evaluated at baseline and repeated at critical points during the course of the patient's illness until death/transplantation. Neutrophil phenotype was determined using fluorochrome-labelled antibodies to CD16/CD11b and assessed by flow cytometry. Neutrophil phagocytic activity (NPA) and capacity (NPC) were determined using FITC-labelled opsonised Escherichia coli. Oxidative burst (OB) was quantified by the percentage of neutrophils producing reactive oxygen species (ROS) and mean fluorescence intensity at rest, and after stimulation with E. coli. Physiological variables, biochemistry, microbiology and outcomes were collected. Plasma pro- and anti-inflammatory cytokine profiles were performed by ELISA.

RESULTS

NPA/NPC was impaired in cirrhosis with the most significant dysfunction being observed in those with advanced disease and in those treated with propranolol. NPC predicted survival in stable cirrhosis [AUROC 0.83 (95% CI 0.68-0.97); P = 0.021] and differentiated survivors from nonsurvivors (90-day P = 0.01; 1 year P < 0.001). Resting OB ≥12% predicted 90-day mortality with 80% sensitivity and 71% specificity [AUROC 0.81 (95% CI 0.64-0.97); P = 0.026 and differentiated survivors from nonsurvivors; P = 0.015].

CONCLUSION

Circulating neutrophils in patients with cirrhosis are dysfunctional and predict the development of infection, organ dysfunction and survival at 90 days and 1 year.

Evidence of neutrophil functional defect despite inflammation in stable cirrhosis

BACKGROUND & AIMS

Deranged neutrophil function in alcoholic hepatitis has been shown to be transmissible to normal neutrophils by patient plasma. The aims of this study were (i) to evaluate whether patients with stable cirrhosis have a similar transmissible neutrophil defect and (ii) to explore the possible mechanisms.

METHODS

Plasma samples from 108 stable cirrhotic patients (Child A or B: 58; Child C: 50) and matched controls were incubated with normal neutrophils. Neutrophil resting respiratory burst, phagocytosis, and toll-like receptors 2, 4, and 9 expressions as well as plasma endotoxin, bacterial DNA, and cytokines were measured. In a separate study, eight patients and five controls were studied using a novel 'skin-window' technique to evaluate neutrophil function in an area of induced sterile inflammation.

RESULTS

Patient plasma induced neutrophil phagocytic dysfunction was greater in patients with more severe disease and was associated with increased expression of toll-like receptors 2 and 4. An increased resting respiratory burst was observed in a subset of patients, showing higher levels of inflammatory cytokines and more pronounced phagocytic impairment. No correlation was found with endotoxemia or bacterial DNA. In patients with compensated cirrhosis and apparently normal neutrophil function, the 'skin-window' study disclosed a severe phagocytic defect at the site of inflammation. Significantly higher levels of neutrophil elastase and IL-8 were found in the blister fluid.

CONCLUSIONS

Stable cirrhosis is characterized by neutrophil phagocytic dysfunction which may be subtle and only revealed in inflamed peripheral tissues where excessive inflammatory mediators continue to be released.

Interleukin-8 is activated in patients with chronic liver diseases and associated with hepatic macrophage accumulation in human liver fibrosis

BACKGROUND

Interleukin-8 (IL-8, CXCL8) is a potent chemoattractant for neutrophils and contributes to acute liver inflammation. Much less is known about IL-8 in chronic liver diseases (CLD), but elevated levels were reported from alcoholic and hepatitis C-related CLD. We investigated the regulation of IL-8, its receptors CXCR1 and CXCR2 and possible IL-8 responding cells in CLD patients.

METHODOLOGY

Serum IL-8 levels were measured in CLD patients (n = 200) and healthy controls (n = 141). Intrahepatic IL-8, CXCR1 and CXCR2 gene expression was quantified from liver samples (n = 41), alongside immunohistochemical neutrophil (MPO) and macrophage (CD68) stainings. CXCR1 and CXCR2 expression was analyzed on purified monocytes from patients (n = 111) and controls (n = 31). In vitro analyses explored IL-8 secretion by different leukocyte subsets.

PRINCIPAL FINDINGS

IL-8 serum levels were significantly increased in CLD patients, especially in end-stage cirrhosis. Interestingly, patients with cholestatic diseases exhibited highest IL-8 serum concentrations. IL-8 correlated with liver function, inflammatory cytokines and non-invasive fibrosis markers. Intrahepatically, IL-8 and CXCR1 expression were strongly up-regulated. However, intrahepatic IL-8 could only be associated to neutrophil infiltration in patients with primary biliary cirrhosis (PBC). In non-cholestatic cirrhosis, increased IL-8 and CXCR1 levels were associated with hepatic macrophage accumulation. In line, CXCR1, but not CXCR2 or CXCR3, expression was increased on circulating monocytes from cirrhotic patients. Moreover, monocyte-derived macrophages from CLD patients, especially the non-classical CD16⁺ subtype, displayed enhanced IL-8 secretion in vitro.

CONCLUSIONS

IL-8 is strongly activated in CLD, thus likely contributing to hepatic inflammation. Our study suggests a novel role of IL-8 for recruitment and activation of hepatic macrophages via CXCR1 in human liver cirrhosis.

Innate immune dysfunction in acute and chronic liver disease

Liver cirrhosis is a common disease causing great public-health concern because of the frequent complications requiring hospital care. Acute liver failure is also prone to several complications but is rare. One of the main complications for both acute and chronic liver diseases is infection, which regularly causes decompensation of cirrhosis, possibly leading to organ failure and death. This review focuses on innate immune function in cirrhosis, acute-on-chronic liver failure and acute liver failure. The known defects of Kupffer cells, neutrophils and monocytes are discussed, together with the pathophysiological importance of gut permeability, portal hypertension and intrinsic cellular defects, and the role of endotoxin, albumin, lipoproteins and toll-like receptors. Based on these different pathomechanisms, the available information on therapeutic strategies is presented. Antibiotic and probiotic treatment, nutritional support, artificial liver support, and experimental strategies such as inhibition of toll-like receptors and use of albumin and colony-stimulating factors are highlighted.

Bacterial translocation increases phagocytic activity of polymorphonuclear leucocytes in portal hypertension: priming independent of liver cirrhosis

AIM

Bacterial translocation (BT) to mesenteric lymph nodes (MLN) in cirrhosis has been linked to impaired host defence. Phagocytosis by polymorphonuclear leucocytes (PMNLs) is the primary event in the killing of bacteria but has not been investigated in relation to the presence of BT.

METHODS

Mesenteric lymph nodes were harvested sterile and assessed for BT by culture techniques. Study groups included ascitic cirrhotic rats (LC), healthy controls (Con) as well as portal-vein-ligated (PVL) rats 2 days (acute PVL with and without norfloxacin) or 3 weeks after surgery (chronic PVL). PMNLs were isolated from systemic blood and the capacity to phagocytose opsonized Escherichia coli was evaluated by FACS analysis.

RESULTS

No BT was observed in Con and chronic PVL animals but 11/20 LC (55%) and six out of six acute PVL (100%) presented with BT. In the presence of BT, PMNL from PVL as well as LC rats showed significantly increased phagocytic activity as compared with controls. In contrast, PMNL from animals without BT, whether PVL or LC, exhibited phagocytic activity similar to those from control rats. The number of PMNLs involved in the phagocytic process was significantly increased only in portal-hypertensive rats with but not without BT as compared with controls. Norfloxacin did prevent BT in acute PVL animals, thereby correcting the increase in phagocytic capacity in PMNL.

CONCLUSIONS

Cirrhosis per se is not associated with alterations of the phagocytic capacity of PMNL. The occurrence of BT, however, increases the phagocytic capacity of PMNL, being observed likewise in prehepatic portal hypertension, indicating an in vivo'priming' of PMNL by BT independent of cirrhosis.

Effect of probiotic treatment on deranged neutrophil function and cytokine responses in patients with compensated alcoholic cirrhosis

BACKGROUND/AIM

Endotoxaemia contributes to neutrophil dysfunction, infection risk and mortality in patients with alcoholic cirrhosis. As probiotics may decrease Gram-negative gut organisms, we hypothesised that probiotic treatment would restore neutrophil function.

METHODS

In an open-label study, patients with alcoholic cirrhosis (n=12) received Lactobacillus casei Shirota (6.5 x 10(9)) 3 times daily for 4 weeks. Data were compared to healthy controls (n=13) and cirrhotic patients (n=8) who did not receive probiotics. Neutrophil oxidative burst, phagocytosis, toll-like-receptor (TLR) expression, plasma cytokines and ex vivo endotoxin-stimulated cytokine production were measured.

RESULTS

Baseline neutrophil phagocytic capacity in patients was significantly lower compared to healthy controls (73% versus 98%, p<0.05), but normalised at the end of the study (n=10, 100%, p<0.05). No improvement was seen in disease controls. Soluble TNF-receptor (sTNFR)-1 and-2 and interleukin (IL)10 were significantly elevated in patients' plasma but did not change during the study. Ex vivo endotoxin-stimulated levels of sTNFR1, sTNFR2 and IL10 were significantly lower at the end of the study (p<0.05). TLR2, 4 and 9 were overexpressed in patients. TLR4 expression normalised by the end of the study.

CONCLUSIONS

Our data provide a proof-of-concept that probiotics restore neutrophil phagocytic capacity in cirrhosis, possibly by changing IL10 secretion and TLR4 expression, warranting larger randomised controlled and mechanistic studies.