Genetic variation in TNFA predicts protection from severe bacterial infections in patients with end-stage liver disease awaiting liver transplantation

Spontaneous Bacterial Peritonitis in Decompensated Liver Cirrhosis—A Literature Review

Background: Spontaneous bacterial peritonitis (SBP) is defined as a bacterial infection of the ascitic fluid without a surgically treatable intra-abdominal infection source. SBP is a common, severe complication in cirrhosis patients with ascites, and if left untreated, in-hospital mortality may exceed 90%. However, the incidence of SBP has been lowered to approx. 20% through early diagnosis and antibiotic therapy. Clinical awareness, prompt diagnosis, and immediate treatment are advised when caring for these patients to reduce mortality and morbidity. Aim: To discuss important issues comprising types of SBP, pathogenesis, bacteriology, including the emergence of multidrug-resistant (MDR) microorganisms, prompt diagnosis, risk factors, prognosis, treatment strategies, as well as recurrence prevention through antibiotic prophylaxis until liver transplantation and future trends in treating and preventing SBP in detail. Methods: This article is a literature review and appraisal of guidelines, randomized controlled trials, meta-analyses, and other review articles found on PubMed from between 1977 and 2022. Results: There are three types of SBP. Bacterial translocation from GI tract is the most common source of SBP. Therefore, two thirds of SBP cases were caused by Gram-negative bacilli, of which Escherichia coli is the most frequently isolated pathogen. However, a trend of Gram-positive cocci associated SBP has been demonstrated in recent years, possibly related to more invasive procedures and long-term quinolone prophylaxis. A diagnostic paracentesis should be performed in all patients with cirrhosis and ascites who require emergency room care or hospitalization, who demonstrate or report consistent signs/symptoms in order to confirm evidence of SBP. Distinguishing SBP from secondary bacterial peritonitis is essential because the conditions require different therapeutic strategies. The standard treatment for SBP is prompt broad-spectrum antibiotic administration and should be tailored according to community-acquired SBP, healthcare-associated or nosocomial SBP infections and local resistance profile. Albumin supplementation, especially in patients with renal impairment, is also beneficial. Selective intestinal decontamination is associated with a reduced risk of bacterial infection and mortality in high-risk group. Conclusions: The standard treatment for SBP is prompt broad-spectrum antibiotic administration and should be tailored according to community-acquired SBP, healthcare-associated or nosocomial SBP infections and local resistance profile. Since the one-year overall mortality rates for SBP range from 53.9 to 78%, liver transplantation should be seriously considered for SBP survivors who are good candidates for transplantation. Further development of non-antibiotic strategies based on pathogenic mechanisms are also urgently needed.

Glucocorticoid Treatment Strategies in Liver Failure

Liver failure is characterized by serious liver decompensation and high mortality. The activation of systemic immune responses and systemic inflammation are widely accepted as the core pathogenesis of liver failure. Glucocorticoids (GCs) are most regularly utilized to suppress excessive inflammatory reactions and immunological responses. GCs have been used in the clinical treatment of liver failure for nearly 60 years. While there has been no unanimity on the feasibility and application of GC treatment in liver failure until recently. The most recent trials have produced conflicting results when it comes to the dose and time for GC therapy of different etiology of liver failure. Our review outlines the issues and options in managing GC treatment in liver failure based on an investigation of the molecular mechanism that GC may give in the treatment.

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.

Functional polymorphisms of innate immunity receptors are not risk factors for the non-SBP type bacterial infections in cirrhosis

BACKGROUND & AIMS

Pattern recognition receptors (PRRs) have a key role in the innate host defense. Functional polymorphisms of various PRRs have been established to contribute to an increased susceptibility to spontaneous bacterial peritonitis (SBP). Their role in the development of cirrhosis-associated bacterial infections (BI), beyond SBP or progressive disease course related to pathological bacterial translocation (BT) remains unknown.

METHODS

Three hundred and forty-nine patients with cirrhosis were genotyped for common NOD2 (R702W, G908R and L1007PfsinsC), TLR2 (-16934T>A), and TLR4 (D299G) variants. Incidence of BIs, decompensating events and liver-related death were assessed in a 5-year follow-up observational study. Pathological BT was assessed based on the presence of antimicrobial antibodies or lipopolysaccharide-binding protein (LBP) level.

RESULTS

In patients with ascites (n = 88) only NOD2 gene variants were associated with an increased cumulative probability of SBP (76.9% ± 19.9%) compared to wild-type (30.9% ± 6.9%, P_LogRank  = .047). Individual or combined PRR genetic profiles were associated with the risk of non-SBP type BI. Advanced disease stage (HR [95% CI]: 2.11 [1.38-3.25]) and prior history of a BI episode (HR: 2.42 [1.58-3.72]) were the major clinical risk factors of a subsequent BI. The risk of a non-SBP type BI in patients with advanced disease and a prior BI was even higher (HR: 4.74 [2.68-8.39]). The frequency of antimicrobial antibodies and LBP levels did not differ between various PRR genotypes. Correspondingly, PRR genetic profile was not able to predict the long-term disease course.

CONCLUSIONS

In cirrhosis, functional polymorphisms of PRRs did not improve the identification of patients with high risk of BI beyond SBP or progressive diseases course.

Lectin-complement pathway molecules are decreased in patients with cirrhosis and constitute the risk of bacterial infections

BACKGROUND & AIMS

Lectin pathway molecules of the complement system are synthesized by hepatocytes and have pivotal role in innate host defence against infectious organisms. Ficolins (FCNs) act as soluble pattern recognition molecules, while mannan-binding lectin serine proteases(MASPs) do as effector molecules in elimination of pathogens. We aimed to study the significance of low level of these molecules in the development of cirrhosis-associated bacterial infections, which has not been elucidated so far.

METHODS

Sera of 266 stable outpatients with cirrhosis and 160 healthy subjects were assayed for a panel of lectin molecules (FCN-2, FCN-3 and MASP-2) by ELISA. In cirrhosis, a 5-year follow-up observational study was conducted to assess a possible association between lectin levels and development of clinically significant bacterial infections(CSI).

RESULTS

FCN-2, FCN-3 and MASP-2 levels were significantly lower in cirrhosis compared to healthy subjects and decreased according to disease severity (P<.001 for all molecules). In Kaplan-Meier analysis, development of CSI was associated with low level of FCN-2 (<427 ng/mL, pLogRank=0.047) and FCN-3 (<4857 ng/mL, pLogRank=0.029), but not with MASP-2 deficiency (<100 ng/mL, pLogRank=0.306). Combined FCN deficiency was associated with increased risk of development of bacterial infections in a step-wise manner. Patients with low level of both FCNs had higher cumulative probability of CSI (63.8%) compared to those with low level of one or normal FCN (52.7% and 45.7%, pLogRank=0.016). Neither FCN serum profile, nor MASP-2 deficiency were associated with infection-related mortality.

CONCLUSIONS

Low level of FCNs associated with hepatic insufficiency might be considered as an additional constituent of cirrhosis-associated immune dysfunction.