Future directions in acute liver failure.

Acute liver failure (ALF) describes a clinical syndrome of rapid hepatocyte injury leading to liver failure manifested by coagulopathy and encephalopathy in the absence of pre-existing cirrhosis. The hallmark diagnostic features are a prolonged prothrombin time (ie, an international normalized ratio of prothrombin time of ≥1.5) and any degree of mental status alteration (HE). As a rare, orphan disease, it seemed an obvious target for a multicenter network. The Acute Liver Failure Study Group (ALFSG) began in 1997 to more thoroughly study and understand the causes, natural history, and management of ALF. Over the course of 22 years, 3364 adult patients were enrolled in the study registry (2614 ALF and 857 acute liver injury-international normalized ratio 2.0 but no encephalopathy-ALI) and >150,000 biosamples collected, including serum, plasma, urine, DNA, and liver tissue. Within the Registry study sites, 4 prospective substudies were conducted and published, 2 interventional ( N -acetylcysteine and ornithine phenylacetate), 1 prognostic [ 13 C-methacetin breath test (MBT)], and 1 mechanistic (rotational thromboelastometry). To review ALFSG's accomplishments and consider next steps, a 2-day in-person conference was held at UT Southwestern Medical Center, Dallas, TX, entitled "Acute Liver Failure: Science and Practice," in May 2022. To summarize the important findings in the field, this review highlights the current state of understanding of ALF and, more importantly, asks what further studies are needed to improve our understanding of the pathogenesis, natural history, and management of this unique and dramatic condition.

The chemokine CXCL14 is a novel early prognostic biomarker for poor outcome in acetaminophen-induced acute liver failure.

BACKGROUND AND AIMS: Patients with acetaminophen-induced acute liver failure are more likely to die while on the liver transplant waiting list than those with other causes of acute liver failure. Therefore, there is an urgent need for prognostic biomarkers that can predict the need for liver transplantation early after an acetaminophen overdose. APPROACH AND RESULTS: We evaluated the prognostic potential of plasma chemokine C-X-C motif ligand 14 (CXCL14) concentrations in patients with acetaminophen (APAP) overdose (n=50) and found that CXCL14 is significantly higher in nonsurviving patients compared to survivors with acute liver failure ( p < 0.001). Logistic regression and AUROC analyses revealed that CXCL14 outperformed the MELD score, better discriminating between nonsurvivors and survivors. We validated these data in a separate cohort of samples obtained from the Acute Liver Failure Study Group (n = 80), where MELD and CXCL14 had similar AUC (0.778), but CXCL14 demonstrated higher specificity (81.2 vs. 52.6) and positive predictive value (82.4 vs. 65.4) for death or need for liver transplantation. Next, combining the patient cohorts and using a machine learning training/testing scheme to mimic the clinical scenario, we found that CXCL14 outperformed MELD based on AUC (0.821 vs. 0.787); however, combining MELD and CXCL14 yielded the best AUC (0.860). CONCLUSIONS: We find in 2 independent cohorts of acetaminophen overdose patients that circulating CXCL14 concentration is a novel early prognostic biomarker for poor outcomes, which may aid in guiding decisions regarding patient management. Moreover, our findings reveal that CXCL14 performs best when measured soon after patient presentation to the clinic, highlighting its importance for early warning of poor prognosis.

Indeterminate etiology of acute liver failure in North America: Less common, still grave prognosis.

BACKGROUND: The etiology of acute liver failure (ALF) remains one of the most important factors in determining prognosis and predicting outcomes. In a significant proportion of ALF cases, however, the etiology remains unknown and is categorized as indeterminate ALF (IND-ALF). In this study, we summarize findings from patients with IND-ALF from 32 transplant centers across the United States, and we compare laboratory, prognostic, and outcome data for patients with IND-ALF. METHODS: Between 1998 and 2019, 3364 adult patients with ALF or acute liver injury (ALI) from 32 liver transplant centers were enrolled in the ALFSG registry. The primary clinical outcome of interest was 21-day transplant-free survival (TFS). RESULTS: Of the 3364 patients enrolled in the ALFSG registry, 3.4 % (n = 114) were adjudicated as true indeterminate. On multivariate analysis, patients with a lower bilirubin, lower INR, lack of use of mechanical ventilation and no clinical features of coma at baseline had a higher odds ratio of transplant free survival. The number of deaths were similar between patients with true-IND ALF versus patients with indeterminable ALF (29.8% vs. 27.2%), with almost half of the patients requiring liver transplant (42.1% vs. 45.7%). CONCLUSION: We illustrate the poor prognoses that true-IND-ALF and indeterminable ALF carry and the need for emergency liver transplantation in most cases.

Role of Hepatitis C Infection in Acute Liver Injury/Acute Liver Failure in North America.

BACKGROUND: While hepatitis A and B are well-known causes of acute liver failure (ALF), few well-documented cases of hepatitis C virus (HCV) infection (absent preexisting liver disease or other liver insults) have been described that result in ALF. We reviewed the Acute Liver Failure Study Group registry for evidence of HCV as a primary or contributing cause to ALF. METHODS: From January 1998 to January 2017, 2,332 patients with ALF (INR ≥ 1.5, any degree of hepatic encephalopathy) and 667 with acute liver injury (ALI; INR ≥ 2.0, no hepatic encephalopathy) were enrolled. Anti-HCV testing was done routinely, with confirmatory RT-PCR testing for HCV RNA where necessary. RESULTS: A total of 136 patients were anti-HCV-antibody positive, as follows: 56 HCV RNA negative, 65 HCV RNA positive, and 8 with no result nor sera available for testing. Only three subjects with ALI/ALF were determined to represent acute HCV infection. Case 1: 47-year-old female with morbid obesity (BMI 52.4) developed ALF and recovered, experiencing anti-HCV seroconversion. Case 2: 37-year-old female using cocaine presented with ALI and fully recovered. Case 3: 54-year-old female developed ALF requiring transplantation and was anti-HCV negative but viremic prior to transplant experiencing anti-HCV seroconversion thereafter. Among 1636 APAP overdose patients, the 52 with concomitant chronic HCV had higher 3-week mortality than the 1584 without HCV (31% vs 17%, p = 0.01). CONCLUSIONS: ALI/ALF solely related to acute hepatitis C infection is very rare. Chronic HCV infection, found in at least 65 (2.2%) of ALI/ALF patients studied, contributed to more severe outcomes in APAP ALI/ALF; ClinicalTrials.gov number, NCT000518440. Trial Registration ClinicalTrials.gov number NCT000518440.

Secular Trends in Severe Idiosyncratic Drug-Induced Liver Injury in North America: An Update From the Acute Liver Failure Study Group Registry.

INTRODUCTION: Idiosyncratic drug-induced liver injury (DILI) is the second leading cause of acute liver failure (ALF) in the United States. Our study aims were to characterize secular trends in the implicated agents, clinical features, and outcomes of adults with DILI ALF over a 20-year period. METHODS: Among 2,332 patients with ALF enrolled in the ALF Study Group registry, 277 (11.9%) were adjudicated as idiosyncratic DILI ALF (INR ≥ 1.5 and hepatic encephalopathy) through expert opinion. The 155 cases in era 1 (January 20, 1998-January 20, 2008) were compared with the 122 cases in era 2 (January 21, 2008-January 20, 2018). RESULTS: Among 277 cases of DILI ALF, 97 different agents, alone or in combination, were implicated: antimicrobials, n = 118 (43%); herbal/dietary supplements (HDS), n = 42 (15%); central nervous system agents/illicit substances, n = 37 (13%); oncologic/biologic agents, n = 29 (10%); and other, n = 51 (18%). Significant trends over time included (i) an increase in HDS DILI ALF (9.7% vs 22%, P < 0.01) and decrease in antimicrobial-induced DILI ALF (45.8% vs. 38.5%, P = 0.03) and (ii) improved overall transplant-free survival (23.5%-38.7%, P < 0.01) while the number of patients transplanted declined (46.4% vs 33.6%, P < 0.03). DISCUSSION: DILI ALF in North America is evolving, with HDS cases rising and other categories of suspect drugs declining. The reasons for a significant increase in transplant-free survival and reduced need for liver transplantation over time remain unclear but may be due to improvements in critical care, increased NAC utilization, and improved patient prognostication.

Changes in Epidemiology of Acetaminophen Overdoses in an Urban County Hospital After 20 Years.

INTRODUCTION: Acetaminophen (APAP) toxicity is the main cause of acute liver failure in the United States. A prior series (1992-1995) identified 71 hospitalized adults with APAP toxicity through the International Statistical Classification of Disease and Related Health Problems, 9th revision (ICD-9) code at Parkland Hospital, Dallas, TX. METHODS: We used a laboratory database search of serum APAP levels from 2011 to 2015 to identify patients with APAP toxicity in the same hospital. RESULTS: We identified 140 patients hospitalized for APAP toxicity from 27,143 APAP levels obtained; 35 required Intensive Care Unit (ICU) admission, and there were no deaths. APAP toxicity/100,000 admissions was similar between eras. DISCUSSION: APAP toxicity continues unabated after 20 years but with improved overall outcomes.

Coagulopathy, Bleeding Events, and Outcome According to Rotational Thromboelastometry in Patients With Acute Liver Injury/Failure.

BACKGROUND AND AIMS: Patients with acute liver injury or failure (ALI/ALF) experience bleeding complications uncommonly despite an abnormal hemostatic profile. Rotational thromboelastometry (ROTEM), which assesses clot formation in whole blood, was used to determine the nature of abnormal hemostasis and whether it contributes to bleeding events, illness severity, or survival. APPROACH AND RESULTS: A total of 200 patients were recruited from sites of the ALF Study Group. Blood collected daily for up to 5 days was analyzed using ROTEM delta devices. Consistent with standard laboratory evidence of hypocoagulability (median international normalized ratio = 2.9 and platelet count = 144 × 109 /L), patients frequently exhibited ROTEM parameters outside the normal range (73% and 62% had abnormalities in clot formation from extrinsic and intrinsic clotting cascades, respectively); however, measures of clot stability were generally normal. Eighteen patients (9%) experienced bleeding events, in whom clot initiation, assembly, and firmness were more severely deranged than patients without bleeding. Abnormal ROTEM parameters were more frequently observed in patients with non-acetaminophen ALI/ALF than those with acetaminophen ALI/ALF (clot initiation [P < 0.001], assembly [P = 0.02], firmness at 10 minutes [P = 0.05], and maximal firmness [P = 0.06]). Patients with more severe systemic complications (high-grade hepatic encephalopathy and need for renal replacement therapy) also had a higher incidence of abnormal ROTEM parameters. Finally, more hypocoagulable ROTEM parameters (clot initiation (P = 0.005), stiffness at 10 minutes (P = 0.05), and maximal stiffness by fibrin assembly (P = 0.004)) were observed in patients who died or underwent liver transplantation than those who survived with their native liver. CONCLUSIONS: In patients with ALI/ALF, abnormal ROTEM parameters are frequent and proportional to disease severity. Whether the increased bleeding risk associated with abnormal ROTEM indicates hemostatic failure or is a proxy for disease severity requires additional study.

Hypochloremia as a novel adverse prognostic factor in acute liver failure.

BACKGROUND AND AIMS: Emerging evidence has identified hypochloremia as an independent predictor for mortality in multiple conditions including cirrhosis. Acute liver failure (ALF) is frequently complicated by electrolyte abnormalities. We investigated the prognostic value of hypochloremia in a large cohort of ALF patients from North America. METHODS: The Acute Liver Failure Study Group (ALFSG) registry is a longitudinal cohort study involving 2588 ALF patients enrolled prospectively from 32 North American academic centres. The primary outcome was a composite of 21-day all-cause mortality or requirement for liver transplantation (death/LT). RESULTS: Patients with hypochloremia (<98 mEq/L) had a significantly higher 21-day mortality rate (42.1%) compared with those with normal (27.5%) or high (>107 mEq/L) chloride (28.0%) (p < .001). There was lower transplant-free cumulative survival in the hypochloremic group than in the normo- or hyper-chloremic groups (log-rank, χ2 24.2, p < .001). Serum chloride was inversely associated with the hazard of 21-day death/LT with multivariable adjustment for known prognostic factors (adjusted hazard ratio [aHR]: 0.977; 95% CI: 0.969-0.985; p < .001). Adding chloride to the ALFSG Prognostic Index more accurately predicted risk of death/LT in 19% of patients (net reclassification improvement [NRI] = 0.19, 95% CI: 0.13-0.25) but underestimated the probability of transplant-free survival in 34% of patients (NRI = -0.34, 95% CI: -0.39 to -0.28). CONCLUSIONS: Hypochloremia is a novel independent adverse prognostic factor in ALF. A new ALFSG-Cl Prognostic Index may improve the sensitivity to identify patients at risk for death without LT.

Acute Liver Failure (ALF) in Pregnancy: How Much Is Pregnancy Related?

BACKGROUND AND AIMS: Acute liver failure (ALF), characterized by sudden onset of coagulopathy (international normalized ratio [INR] ≥ 1.5) and encephalopathy, may occur during pregnancy either as a pregnancy-associated etiology or an unrelated and coincidental liver injury. The U.S. Acute Liver Failure Study Group, comprised of 33 tertiary care liver centers, has enrolled consecutive patients with ALF or acute liver injury (ALI; INR ≥ 2.0 with no encephalopathy), over two decades. APPROACH AND RESULTS: Etiologies, clinical features, and outcomes of 70 of 3,155 patients (2.2%) who developed ALF or ALI during pregnancy were reviewed to determine how many were pregnancy associated (pregnancy-associated liver disease; PAALD) and how many were attributed to other etiologies. Thirty-five of the 70 were considered PAALD, of whom nearly half were attributed to hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome and half to acute fatty liver of pregnancy (AFLP), although, in some instances, the distinction was unclear. Virtually all with PAALD had been delivered before hepatology referral, mostly by cesarean section. Acetaminophen toxicity accounted for 21 (60% of the remaining cases), with the remainder resulting from a variety of other causes, but not including viral hepatitis A through E. Although recovery with delivery or supportive measures was possible in most cases, 11 of 70 (16%) required liver transplantation and 8 (11%) died. Swansea criteria to diagnose AFLP were met by all patients with PAALD and also by virtually all women with other forms of ALF. CONCLUSIONS: Only half of those with ALF during pregnancy appeared to have HELLP or AFLP. Morbidity and mortality for mother and fetus are strongly associated with etiology of liver failure.

Outcomes of Acute Liver Injury in Adults Due to Wilson's Disease: Is Survival Without Transplant Possible?

Wilson's disease (WD) is a rare cause of acute liver failure (ALF) that is thought to have a uniformly fatal outcome without liver transplantation (LT). Previous studies proposed diagnostic and prognostic criteria for WD-ALF. It is not known whether these apply to WD patients presenting as severe acute liver injury (ALI) without encephalopathy. From 2008 to 2018, 822 patients with ALI in the US Acute Liver Failure Study Group (ALFSG) registry were enrolled and prospectively followed. The diagnosis of WD-ALI was confirmed in 8 patients. Serum biochemical diagnostic ratios predicting WD-ALF (alkaline phosphatase [ALP]:total bilirubin(TB) and aspartate aminotransferase [AST]:alanine aminotransferase [ALT]) were determined in these patients, and predictors of prognosis for WD-ALI were evaluated. Of these 8 ALI-WD patients, 5 received an LT. Ratios of both ALP:TB of <4 and AST:ALT of >2.2 on study admission were met in 4 LT patients. All LT patients were female. The Model for End-Stage Liver Disease scores on admission were generally higher in LT patients. All transplanted patients had an initial revised WD score of >11 (>10 predicting poor outcome without LT in WD-ALF), whereas in non-LT patients, 2 had scores of 9, and 1 a score of 13. Also, 3 LT patients were started on chelation therapy, 2 were started on plasmapheresis, and 1 was started on Molecular Adsorbent Recirculating System therapy. All non-LT patients were treated with chelation. At 21 days, all patients were alive and discharged from the hospital. In conclusion, some patients with ALI due to WD may survive without LT. Revised Wilson index scores >10 predict poor outcome in most patients with WD-ALI, as they do for WD-ALF, and they correlate positively with the ALI model in this cohort. Biochemical ratios for WD diagnosis appear more applicable to ALF compared with WD-ALI.

Changes in alpha-foetoprotein and Gc-globulin in relation to outcomes in non-acetaminophen acute liver failure.

BACKGROUND: Changes in Gc-globulin (Gc) and in alpha-foetoprotein (AFP) have been shown to be related to outcome in patients with acute liver failure (ALF). Gc is a serum protein that complexes with intravascular actin released during cellular necrosis. AFP, also made by hepatocytes, is associated with hepatocellular growth and regeneration. Previously, low absolute levels or decreases over time in either AFP or Gc portended to be a poor outcome. METHODS: In a retrospective analysis of the double-blind trial of intravenous N-acetylcysteine (NAC) for ALF not because of acetaminophen, sera on days 1 and 3 or days 2 and 4 following admission were available to measure AFP in 70 patients and Gc in 66 patients. Mann-Whitney U tests were performed on the admission values, the absolute change and the fractional change of AFP and Gc to compare TFS (transplant-free survival) and non-TFS (death or transplantation). Logistic regression and receiver operating characteristic (ROC) analyses were performed to evaluate the markers in comparison and in addition to King's College Criteria (KCC). RESULTS: Transplant-free survival patients were characterized by increases in AFP, whereas non-TFS had significantly different (negative) absolute and fractional changes (P < .01). The addition of declining AFP levels to KCC improved the area under the curve in predicting non-TFS (AUC >70%). Gc globulin values did not differ between TFS and non-TFS in the 2-day intervals studied (P> .2). CONCLUSION: In this comparison of two prognostic markers in patients with non-acetaminophen-induced ALF, rising AFP but not rising Gc levels was associated with TFS. TRIAL REGISTRATION: ClinicalTrials.gov number NCT00004467.

Plasma osteopontin in acute liver failure.

BACKGROUND: Osteopontin (OPN) is a novel phosphoglycoprotein expressed in Kupffer cells that plays a pivotal role in activating natural killer cells, neutrophils and macrophages. Measuring plasma OPN levels in patients with acute liver failure (ALF) might provide insights into OPN function in the setting of massive hepatocyte injury. METHODS: OPN levels were measured using a Quantikine® ELISA assay on plasma from 105 consecutive ALF patients enrolled by the US Acute Liver Failure Study Group, as well as controls including 40 with rheumatoid arthritis (RA) and 35 healthy subjects both before, and 1 and 3 days after undergoing spine fusion (SF) surgery as a model for acute inflammation. RESULTS: Median plasma OPN levels across all etiologies of ALF patients were elevated 10- to 30-fold: overall median 1055ng/mL; range: 33-19,127), when compared to healthy controls (median in pre-SF patients: 41ng/mL; range 2.6-86.4). RA and SF post op patients had elevated OPN levels (37ng/mL and 198ng/mL respectively), well below those of the ALF patients. Median OPN levels were highest in acetaminophen (3603ng/mL) and ischemia-related ALF (4102ng/mL) as opposed to viral hepatitis (706ng/mL), drug-induced liver injury (353ng/mL) or autoimmune hepatitis (436ng/mL), correlating with the degree of hepatocellular damage, as reflected by aminotransferase values (R value: 0.47 for AST, p<0.001). CONCLUSIONS: OPN levels appeared to correlate with degree of liver necrosis in ALF. Very high levels were associated with hyperacute injury and good outcomes. Whether OPN exerts a protective effect in limiting disease progression in this setting remains uncertain.

Whole Exome Sequencing Reveals Genetic Variants in HLA Class II Genes Associated With Transplant-free Survival of Indeterminate Acute Liver Failure.

INTRODUCTION: Indeterminate acute liver failure (IND-ALF) is a rare clinical syndrome with a high mortality rate. Lacking a known etiology makes rapid evaluation and treatment difficult, with liver transplantation often considered as the only therapeutic option. Our aim was to identify genetic variants from whole exome sequencing data that might be associated with IND-ALF clinical outcomes. METHODS: Bioinformatics analysis was performed on whole exome sequencing data for 22 patients with IND-ALF. A 2-tier approach was used to identify significant single-nucleotide polymorphisms (SNPs) associated with IND-ALF clinical outcomes. Tier 1 identified the SNPs with a higher relative risk in the IND-ALF population compared with those identified in control populations. Tier 2 determined the SNPs connected to transplant-free survival and associated with model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. RESULTS: Thirty-one SNPs were found associated with a higher relative risk in the IND-ALF population compared with those in controls, of which 11 belong to the human leukocyte antigen (HLA) class II genes but none for the class I. Further analysis showed that 5 SNPs: rs796202376, rs139189937, and rs113473719 of HLA-DRB5; rs9272712 of HLA-DQA1; and rs747397929 of IDO1 were associated with a higher probability of IND-ALF transplant-free survival. Using 3 selected SNPs, a model for the polygenic risk score was developed to predict IND-ALF prognoses, which are comparable with those by model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. DISCUSSION: Certain gene variants in HLA-DRB5, HLA-DQA1, and IDO1 were found associated with IND-ALF transplant-free survival. Once validated, these identified SNPs may help elucidate the mechanism of IND-ALF and assist in its diagnosis and management.

Hypophosphatemia in acute liver failure of a broad range of etiologies is associated with phosphaturia without kidney damage or phosphatonin elevation.

Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.

α-Glutathione S-Transferase: A New Biomarker for Liver Injury?

BACKGROUND: Serum alanine and aspartate aminotransferases (ALT/AST) have been the gold standard for detection and quantification of liver injury for over 6 decades, but have relatively long half-lives (T½) (literature estimates approximately 17 and 47 h, respectively) and thus do not reflect immediate changes in liver injury or recovery. A new point-of-care immunoassay for α-glutathione S-transferase (α-GST) measures this cytosolic liver enzyme with a predicted T½ of 60-90 min based on preliminary studies and might enable earlier detection of improving or worsening liver injury than conventional enzyme testing. METHODS: Serial serum samples collected daily from 31 patients enrolled in the Acute Liver Failure Study Group, with acetaminophen (APAP) toxicity, drug-induced liver injury, ischemic hepatopathy (IH), or autoimmune hepatitis were analyzed to determine α-GST using the Qualigen FastPack® α-GST Assay (Carlsbad), a chemiluminescent immunoassay using a paramagnetic particle matrix with an upper limit of normal of 11 ng/mL. AST and ALT values were obtained from the medical record and have an upper limit of normal of 40 IU/L. The T½ values for α-GST, AST, and ALT were calculated from the peak value for APAP and IH etiologies considered as single time point injuries, using an exponential trendline equation of the serial values. RESULTS: Median α-GST for all etiologies were increased on day 1, returning to normal by day 3, whereas median AST and ALT values did not return to normal, even at day 7. The median T½ for α-GST, AST, and ALT were 6.4, 22.2, and 33.9 h, respectively. CONCLUSIONS: α-GST is a more responsive marker of liver injury/recovery, allowing for more rapid real-time assessment of improvement or worsening of liver disease.

Procalcitonin Identifies Cell Injury, Not Bacterial Infection, in Acute Liver Failure.

BACKGROUND: Because acute liver failure (ALF) patients share many clinical features with severe sepsis and septic shock, identifying bacterial infection clinically in ALF patients is challenging. Procalcitonin (PCT) has proven to be a useful marker in detecting bacterial infection. We sought to determine whether PCT discriminated between presence and absence of infection in patients with ALF. METHOD: Retrospective analysis of data and samples of 115 ALF patients from the United States Acute Liver Failure Study Group randomly selected from 1863 patients were classified for disease severity and ALF etiology. Twenty uninfected chronic liver disease (CLD) subjects served as controls. RESULTS: Procalcitonin concentrations in most samples were elevated, with median values for all ALF groups near or above a 2.0 ng/mL cut-off that generally indicates severe sepsis. While PCT concentrations increased somewhat with apparent liver injury severity, there were no differences in PCT levels between the pre-defined severity groups-non-SIRS and SIRS groups with no documented infections and Severe Sepsis and Septic Shock groups with documented infections, (p = 0.169). PCT values from CLD patients differed from all ALF groups (median CLD PCT value 0.104 ng/mL, (p ≤0.001)). Subjects with acetaminophen (APAP) toxicity, many without evidence of infection, demonstrated median PCT >2.0 ng/mL, regardless of SIRS features, while some culture positive subjects had PCT values <2.0 ng/mL. SUMMARY/CONCLUSIONS: While PCT appears to be a robust assay for detecting bacterial infection in the general population, there was poor discrimination between ALF patients with or without bacterial infection presumably because of the massive inflammation observed. Severe hepatocyte necrosis with inflammation results in elevated PCT levels, rendering this biomarker unreliable in the ALF setting.