Pharmacogenomics of drug-induced liver injury (DILI): Molecular biology to clinical applications

Incidence, risk factors and outcomes of checkpoint inhibitor-induced liver injury: A 10-year real-world retrospective cohort study

Background & Aims

Checkpoint inhibitors (CPI) account for increasing numbers of drug-induced liver injury (DILI) cases. We aimed to determine the incidence rate and risk factors associated with checkpoint inhibitor-induced liver injury (ChILI).

Methods

Prescription event monitoring was performed on all melanoma and renal cancer patients who received CPI at a tertiary centre between 2011 and 2021. ChILI cases were identified using the definitions, grading, and causality assessment methods validated for DILI. We assessed risk factors associated with ChILI in CPI-naive patients using multivariable logistic regression model. Consecutive patients with suspected ChILI from two other tertiary centres were adjudicated and combined for case characterisation and outcomes of ChILI.

Results

Out of 432 patients who received CPI over 10 years, ChILI occurred in 38 (8.8%) with an overall incidence rate of 11.5 per 1,000 person-months (95% CI 8.2-15.8). Probability of ChILI was highest in combination therapy (32%) and no new events occurred beyond 135 days of treatment. Risk factor analysis showed that combination therapy, female sex, higher baseline alanine transferase level and lower baseline alkaline phosphatase level were independently associated with higher risk of ChILI. In total, 99 patients were adjudicated to have ChILI from three centres. Although Common Terminology Criteria for Adverse Events classified 20 patients (20.2%) to have 'life-threatening' grade 4 hepatitis, ChILI severity was graded as mild in 45 (45.5%) and moderate in the remaining 54 (54.5%) cases.

Conclusions

The real-world risk of ChILI is higher than previously reported. Among patients receiving dual CPI, this risk falls markedly after 4.5 months. As Common Terminology Criteria for Adverse Events overestimates its clinical severity, case-definition, evaluation and management of ChILI should be revised to harmonise care.

Impact and implications

Using prescription event monitoring over a 10-year period, the incidence rate of checkpoint inhibitor induced liver injury (ChILI) based on established case definitions for drug-induced liver injury (DILI) is 11.5 per 1,000 person-months. Formal causality assessment identified an alternative cause in 19% of patients with suspected ChILI highlighting the importance of systematic evaluation by clinicians to minimise unnecessary immunosuppression. Intensity of monitoring in patients receiving combination therapy regime after 4.5 months of therapy can be reduced as the risk of new onset ChILI beyond this point is minimal. Current Common Terminology Criteria for Adverse Events (CTCAE) grading overestimates clinical severity of ChILI and hence contributes to avoidable hospitalisation.

Drug-Induced Liver Injury with Commonly Used Antibiotics in the All of Us Research Program

Antibiotics are a known cause of idiosyncratic drug-induced liver injury (DILI). According to the Centers for Disease Control and Prevention, the five most commonly prescribed antibiotics in the United States are azithromycin, ciprofloxacin, cephalexin, amoxicillin, and amoxicillin-clavulanate. We quantified the frequency of acute DILI for these common antibiotics in the All of Us Research Program, one of the largest electronic health record (EHR)-linked research cohorts in the United States. Retrospective analyses were conducted applying a standardized phenotyping algorithm to de-identified clinical data available in the All of Us database for 318,598 study participants. Between February 1984 and December 2022, more than 30% of All of Us participants (n = 119,812 individuals) had been exposed to at least 1 of our 5 study drugs. Initial screening identified 591 potential case patients that met our preselected laboratory-based phenotyping criteria. Because DILI is a diagnosis of exclusion, we then used phenome scanning to narrow the case counts by (i) scanning all EHRs to identify all alternative diagnostic explanations for the laboratory abnormalities, and (ii) leveraging International Classification of Disease 9th revision (ICD)-9 and ICD 10th revision (ICD)-10 codes as exclusion criteria to eliminate misclassification. Our final case counts were 30 DILI cases with amoxicillin-clavulanate, 24 cases with azithromycin, 24 cases with ciprofloxacin, 22 cases with amoxicillin alone, and < 20 cases with cephalexin. These findings demonstrate that data from EHR-linked research cohorts can be efficiently mined to identify DILI cases related to the use of common antibiotics.

Human embryonic stem cell-derived immunity-and-matrix regulatory cells promote intrahepatic cell renewal to rescue acute liver failure

Acute liver failure (ALF) is a clinical syndrome characterized by the accelerated development of hepatocyte necrosis and significant mortality. Given that liver transplantation is now the only curative treatment available for ALF, there is an urgent need to explore innovative therapies. Mesenchymal stem cells (MSCs) have been applied in preclinical studies for ALF. It had been demonstrated that human embryonic stem cell-derived immunity-and-matrix regulatory cells (IMRCs) met the properties of MSCs and had been employed in a wide range of conditions. In this study, we conducted a preclinical evaluation of IMRCs in the treatment of ALF and investigated the mechanism involved. ALF was induced in C57BL/6 mice via intraperitoneal administration of 50% CCl₄ (6 mL/kg) mixed with corn oil, followed by intravenous injection of IMRCs (3 × 10⁶ cells/each). IMRCs improved histopathological changes in the liver and reduced alanine transaminase (ALT) or aspartate transaminase (AST) levels in serum. IMRCs also promoted cell renewal in the liver and protected it from CCl₄ damage. Furthermore, our data indicated that IMRCs protected against CCl₄-induced ALF by regulating the IGFBP2-mTOR-PTEN signaling pathway, which is associated with the repopulation of intrahepatic cells. Overall, IMRCs offered protection against CCl₄-induced ALF and were capable of preventing apoptosis and necrosis in hepatocytes, which provided a new perspective for treating and improving the prognosis of ALF.

Identification of Reduced ERAP2 Expression and a Novel HLA Allele as Components of a Risk Score for Susceptibility to Liver Injury Due to Amoxicillin-Clavulanate

BACKGROUND & AIMS

Drug-induced liver injury (DILI) due to amoxicillin-clavulanate (AC) has been associated with HLA-A∗02:01, HLA-DRB1∗15:01, and rs2476601, a missense variant in PTPN22. The aim of this study was to identify novel risk factors for AC-DILI and to construct a genetic risk score (GRS).

METHODS

Transcriptome-wide association study and genome-wide association study analyses were performed on 444 AC-DILI cases and 10,397 population-based controls of European descent. Associations were confirmed in a validation cohort (n = 133 cases and 17,836 population-based controls). Discovery and validation AC-DILI cases were also compared with 1358 and 403 non-AC-DILI cases.

RESULTS

Transcriptome-wide association study revealed a significant association of AC-DILI risk with reduced liver expression of ERAP2 (P = 3.7 × 10-7), coding for an aminopeptidase involved in antigen presentation. The lead eQTL single nucleotide polymorphism, rs1363907 (G), was associated with AC-DILI risk in the discovery (odds ratio [OR], 1.68; 95% CI, 1.23-1.66; P = 1.7 × 10-7) and validation cohorts (OR, 1.2; 95% CI, 1.04-2.05; P = .03), following a recessive model. We also identified HLA-B∗15:18 as a novel AC-DILI risk factor in both discovery (OR, 4.19; 95% CI, 2.09-8.36; P = 4.9 × 10-5) and validation (OR, 7.78; 95% CI, 2.75-21.99; P = .0001) cohorts. GRS, incorporating rs1363907, rs2476601, HLA-B∗15:18, HLA-A∗02:01, and HLA-DRB1∗15:01, was highly predictive of AC-DILI risk when cases were analyzed against both general population and non-AC-DILI control cohorts. GRS was the most significant predictor in a regression model containing known AC-DILI clinical risk characteristics and significantly improved the predictive model.

CONCLUSIONS

We identified novel associations of AC-DILI risk with ERAP2 low expression and with HLA-B∗15:18. GRS based on the 5 risk variants may assist AC-DILI causality assessment and risk management.

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.

Corticosteroid plus glycyrrhizin therapy for chronic drug- or herb-induced liver injury achieves biochemical and histological improvements: a randomised open-label trial

BACKGROUND

Treatment of chronic drug-induced liver injury (DILI) or herb-induced liver injury(HILI) is an important and unresolved challenge. There is no consensus regarding the indications for corticosteroids for chronic DILI/HILI.

AIMS

To investigate the efficacy and safety of corticosteroid plus glycyrrhizin for patients with chronic DILI/HILI.

METHODS

This was a randomised open-label trial. Eligible patients with causality assessment using the updated RUCAM were randomly assigned (1:1) either to the steroid treatment group (48-week stepwise dose reduction of methylprednisolone plus glycyrrhizin) or control group (glycyrrhizin alone). Liver biopsies were performed at baseline and at the end of the 48-week treatment period. The primary outcome was the proportion of patients with sustained biochemical response (SBR). The secondary outcomes were improvement in liver histology, time to biochemical normalisation and safety.

RESULTS

Of 80 participants, 70 (87.5%) completed the trial. The patients were predominantly female (77.5%), aged >40 years (77.5%) and had a hepatocellular injury pattern of DILI (71.2%). Compared to the control group, the treatment group showed a higher proportion of SBR (94.3% vs. 71.4%, p = 0.023), shorter biochemical normalisation time and histological improvements in both histological activity and fibrosis. The DILI and HILI subgroups, as well as the autoimmune hepatitis (AIH)-like DILI and non-AIH-like subgroups, showed comparable responses. No severe adverse events were observed during the trial.

CONCLUSION

This study provides the first clinical evidence that corticosteroid plus glycyrrhizin therapy for chronic DILI with or without AIH-like features can achieve both biochemical response and histological improvements with good safety. (ClinicalTrials.gov, NCT02651350).

Clinical characteristics and outcomes of drug-induced liver injury in Taiwan: With emphasis on the impact of chronic hepatitis B infection

BACKGROUND

Whether hepatitis B virus (HBV) infection can affect the outcomes of drug-induced liver injury (DILI) is controversial. This study aimed to evaluate the characteristics and outcomes of DILI in Taiwan, with an emphasis on the impact of HBV infection.

METHODS

We prospectively recruited patients with DILI from multiple centers in Taiwan from 2010 to 2018.

RESULTS

A total of 1,014 patients were enrolled. The leading culprit drug category was antimicrobials (481, 47.4%), followed by nonsteroidal anti-inflammatory drugs, anticonvulsants, and statins. Among the antimicrobials, antituberculosis agents were most likely to induce liver injury (257, 25.3%), followed by antibacterial, antifungal, and antiviral agents. The liver-related mortality rate was 8.2% (83/1,014). The patients who died had higher rates of hepatocellular-type liver injury, elevated liver biochemical tests, preexisting liver cirrhosis, jaundice, chronic HBV infection, and antituberculosis drug-induced liver injury (ATDILI) than the survivors. A total of 131 patients (12.9%) with DILI were HBV carriers, of whom 23 (17.6%) died of hepatic failure. The rate of HBV-DNA > 2000 IU/mL was higher in the patients who died (47.8% vs. 26.9%, p = 0.047) than in the survivors. After adjusting for possible risk factors, active HBV infection with HBV-DNA > 2000 IU/mL was the most significant risk factor for liver-related mortality (adjusted HR, 4.40, 95% CI, 2.31%-8.38%, p < 0.001). The other independent risk factors for mortality were ATDILI and albumin-bilirubin (ALBI) score (adjusted HR, 1.25 and 4.09, respectively, p < 0.003).

CONCLUSION

Antituberculosis agents were the leading cause of DILI in Taiwanese, and they were associated with poorer outcomes than other drug categories. Active HBV infection, ATDILI and ALBI score were independent risk factors for fatal DILI. Close monitoring of liver tests and timely antiviral therapy should be implemented in HBV carriers during the administration of high-risk drugs, such as antituberculosis agents.

From Pharmacogenetics to Pharmaco-Omics:Milestones and Future Directions

The origins of pharmacogenetics date back to the 1950s, when it was established that inter-individual differences in drug response are partially determined by genetic factors. Since then, pharmacogenetics has grown into its own field, motivated by the translation of identified gene-drug interactions into therapeutic applications. Despite numerous challenges ahead, our understanding of the human pharmacogenetic landscape has greatly improved thanks to the integration of tools originating from disciplines as diverse as biochemistry, molecular biology, statistics, and computer sciences. In this review, we discuss past, present, and future developments of pharmacogenetics methodology, focusing on three milestones: how early research established the genetic basis of drug responses, how technological progress made it possible to assess the full extent of pharmacological variants, and how multi-dimensional omics datasets can improve the identification, functional validation, and mechanistic understanding of the interplay between genes and drugs. We outline novel strategies to repurpose and integrate molecular and clinical data originating from biobanks to gain insights analogous to those obtained from randomized controlled trials. Emphasizing the importance of increased diversity, we envision future directions for the field that should pave the way to the clinical implementation of pharmacogenetics.

Infliximab-induced liver injury: Clinical phenotypes, autoimmunity and the role of corticosteroid treatment

BACKGROUND & AIMS

Infliximab has been associated with drug-induced liver injury (DILI), particularly drug-induced autoimmune hepatitis (DIAIH). DIAIH is commonly treated with corticosteroids, but there is limited data on the efficacy of corticosteroids in infliximab-induced DILI.

METHODS

Patients were included for assessment if they had been treated with infliximab between 2009-2020 in Iceland and had developed elevated liver tests. Other specific etiologies of liver enzyme elevations were excluded. Patients treated with corticosteroids were compared to patients not receiving corticosteroids.

RESULTS

A total of 36 patients with infliximab-induced DILI were identified: median age was 46 years (IQR 32-54) and 28 (78%) were female. Type of liver injury was predominantly hepatocellular (64%). Median peak liver enzymes were: alanine aminotransferase (ALT) 393 (328-695) U/L, aspartate aminotransferase 283 (158-564) U/L, alkaline phosphatase 116 (83-205) U/L, and bilirubin (10-20) 13 μmol/L. A total of 25 (69%) were positive for anti-nuclear antibody and/or had elevated IgG. Corticosteroids were initiated in 17 (47%). Median time from onset of liver injury to peak ALT value was longer in patients treated with corticosteroids, 22 (12-59) vs. 0 (0-3) days (p = 0.001). Time from peak ALT to normalization of liver enzymes was 45 days in the corticosteroid group vs. 77 days in others (p = 0.062). Corticosteroids were tapered in all patients, with no cases of relapse during the follow-up period of 1,245 (820-2,698) days. Overall 75% received another biologic, mostly adalimumab, without evidence of liver injury.

CONCLUSION

Approximately half of patients with infliximab-induced liver injury had slow improvement in ALT despite cessation of therapy and were treated with corticosteroids. Treatment response was good with prompt resolution of liver test abnormalities. Relapse of liver injury was not observed after tapering of corticosteroids despite prolonged follow-up and no patients developed DILI due to a second biologic.

LAY SUMMARY

A rare side effect of infliximab, a biologic medicine used to treat multiple inflammatory diseases, is liver injury and liver inflammation. Steroid treatment has been used in some patients with liver injury caused by infliximab, but there have been few studies supporting this treatment. In this study of 36 patients with infliximab-induced liver injury, approximately half of patients were treated with steroids and the results suggest that patients receiving steroids recover more quickly.

Drug-induced hepatocellular injury due to herbal supplement ashwagandha

A 39-year-old female presented with a one-week history of jaundice and nausea after taking an over-the-counter herbal supplement containing ashwagandha root extract. Initial investigations revealed a hepatocellular pattern of liver enzyme abnormality with jaundice. Investigations, including viral serology, liver specific autoantibodies and an ultrasound scan of the abdomen, were unremarkable. Liver biopsy showed an acute cholestatic hepatitis with confluent necrosis but no features of chronicity. These histopathological findings differ to that of a previously reported case. Review of recent literature revealed that some clinical features and the time course of liver injury were similar to previous reports of ashwagandha drug-induced liver injury (DILI). The patient received treatment with ursodeoxycholic acid. We compare this case to previous reported cases of ashwagandha DILI and discuss the biochemical and histopathological features of ashwagandha DILI, therapeutic strategies and the importance of recognising herbal supplements as a possible cause of DILI.

Biomarkers of idiosyncratic drug-induced liver injury (DILI) - a systematic review

INTRODUCTION

Idiosyncratic drug-induced liver injury (DILI) is an unpredictable event, and there are no specific biomarkers that can distinguish DILI from alternative explanations or predict its clinical outcomes.

AREAS COVERED

This systematic review summarizes the available evidence for all biomarkers proposed to have a role in the diagnosis or prognosis of DILI. Following a comprehensive search, we included all types of studies in humans. We included DILI cases based on any threshold criteria but excluded intrinsic DILI, commonly caused by paracetamol overdose. We classified studies into diagnostic and prognostic categories and assessed their methodological quality. After reviewing the literature, 14 studies were eligible.

EXPERT OPINION

Diagnostic studies were heterogeneous with regard to the study population and outcomes measured. Prognostic models were developed by integrating novel biomarkers, risk scores, and traditional biomarkers, which increased their prognostic ability to predict death or transplantation by 6 months. This systematic review highlights the case of need for non-genetic biomarkers that distinguish DILI from acute liver injury related to alternative etiology. Biomarkers with the potential to identify serious adverse outcomes from acute DILI should be validated in independent prospective cohorts with a substantial number of cases.

The Immunological Mechanisms and Immune-Based Biomarkers of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) has become one of the major challenges of drug safety all over the word. So far, about 1,100 commonly used drugs including the medications used regularly, herbal and/or dietary supplements, have been reported to induce liver injury. Moreover, DILI is the main cause of the interruption of new drugs development and drugs withdrawn from the pharmaceutical market. Acute DILI may evolve into chronic DILI or even worse, commonly lead to life-threatening acute liver failure in Western countries. It is generally considered to have a close relationship to genetic factors, environmental risk factors, and host immunity, through the drug itself or its metabolites, leading to a series of cellular events, such as haptenization and immune response activation. Despite many researches on DILI, the specific biomarkers about it are not applicable to clinical diagnosis, which still relies on the exclusion of other causes of liver disease in clinical practice as before. Additionally, circumstantial evidence has suggested that DILI is mediated by the immune system. Here, we review the underlying mechanisms of the immune response to DILI and provide guidance for the future development of biomarkers for the early detection, prediction, and diagnosis of DILI.

Hepatotoxicity of iodine-131 ablation for post-surgical differentiated thyroid cancer patients with hepatitis B virus infection

OBJECTIVE

Radioiodine (Iodine-131, ¹³¹I) ablation is a standard treatment for differentiated thyroid cancer (DTC) after thyroidectomy. Hepatotoxicity is a rare side effect of ¹³¹I, and little information is available on the hepatotoxicity of ¹³¹I ablation for post-surgical DTC patients with hepatitis B virus (HBV) infection.

METHODS

We performed a retrospective study of 94 post-surgical DTC patients between November 2012 and August 2015 in our hospital. All the patients had been screened for HBV infection and divided into HBV group and non-HBV group. Clinical data were compared between the two groups.

RESULTS

14 patients with HBV infection and 80 patients without HBV infection were analyzed. The baseline characteristics of the two groups had no statistical differences. Incidence of hepatotoxicity was higher in HBV group than in non-HBV group and HBV infection was confirmed as a risk factor of hepatotoxicity by univariate and multivariate regression analysis.

CONCLUSION

Post-surgical DTC patients with HBV infection were prone to hepatotoxicity by ¹³¹I ablation treatment. Physicians should pay more attention to the liver function of patients at risk.

Machine Learning to Identify Interaction of Single-Nucleotide Polymorphisms as a Risk Factor for Chronic Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major cause of drug development failure and drug withdrawal from the market after approval. The identification of human risk factors associated with susceptibility to DILI is of paramount importance. Increasing evidence suggests that genetic variants may lead to inter-individual differences in drug response; however, individual single-nucleotide polymorphisms (SNPs) usually have limited power to predict human phenotypes such as DILI. In this study, we aim to identify appropriate statistical methods to investigate gene-gene and/or gene-environment interactions that impact DILI susceptibility. Three machine learning approaches, including Multivariate Adaptive Regression Splines (MARS), Multifactor Dimensionality Reduction (MDR), and logistic regression, were used. The simulation study suggested that all three methods were robust and could identify the known SNP-SNP interaction when up to 4% of genotypes were randomly permutated. When applied to a real-life DILI chronicity dataset, both MARS and MDR, but not logistic regression, identified combined genetic variants having better associations with DILI chronicity in comparison to the use of individual SNPs. Furthermore, a simple decision tree model using the SNPs identified by MARS and MDR was developed to predict DILI chronicity, with fair performance. Our study suggests that machine learning approaches may help identify gene-gene interactions as potential risk factors for better assessing complicated diseases such as DILI chronicity.

Herb-Induced Liver Injury Related to Reynoutria multiflora (Thunb.) Moldenke: Risk Factors, Molecular and Mechanistic Specifics

Herbal medicine is widely used in Asia as well as the west. Hepatotoxicity is one of the most severe side effects of herbal medicine which is an increasing concern around the world. Reynoutria multiflora (Thunb.) Moldenke (Polygonum multiflorum Thunb., PM) is the most common herb that can cause herb-induced liver injury (HILI). The recent scientific and technological advancements in clinical and basic research are paving the way for a better understanding of the molecular aspects of PM-related HILI (PM-HILI). This review provides an updated overview of the clinical characteristics, predisposing factors, hepatotoxic components, and molecular mechanisms of PM-HILI. It can also aid in a better understanding of HILI and help in further research on the same.

Research status and progress of drug induced liver injury

The incidence rate of drug-induced liver injury has been high with the extensive use of drugs and the development and application of new drugs. The pathogenesis of drug-induced liver injury is not fully understood, so there is no significant breakthrough in its treatment. The diagnosis of drug-induced liver injury still depends on drug history, clinical manifestations, imaging, biochemical tests, and liver biopsy. This article reviews the recent progress in the understanding of the incidence rate, classification, risk factors, and serum markers of drug-induced liver injury.

Molecular fingerprinting by single cell clone analysis in adverse drug reaction (ADR) assessment

Causality assessment for idiosyncratic ADRs mainly relies on epidemiology, signal detection and less often on proven or plausible mechanistic evidence of the drug at a cellular or organ level. Distinct clones of cells can exist within organs of individual patients, some conferring susceptibility to well recognised adverse drug reactions (ADRs). Recent advances in molecular biology has allowed the development of single cell clonal techniques, including single cell RNA sequencing (scRNA-seq) to molecularly fingerprint ADRs and distinguish between distinct clones of cells within organs in individuals, which may confer differing susceptibilities to ADRs. ScRNA-seq permits molecular fingerprinting of some serious ADRs, mainly in the skin, through identification of directly expressed genes (DEG) of interest within specific clones. Overexpressed DEGs provides an opportunity for targeted treatment strategies to be developed. scRNA-seq could be applied to a number of other ADRs involving tissues that can be biopsied/sampled (including skin, liver, kidney, blood, stem cells) as well as providing a molecular basis for rapid screening of potential therapeutic candidates, which may not otherwise be predictable from class of toxicity/organ involvement. . A framework for putative assessment for ADRs using scRNA-seq is proposed as well as speculating on potential regulatory implications for pharmacovigilance and drug development. Molecular fingerprinting of ADRs using scRNA-seq may allow better targeting for enhanced pharmacovigilance and risk minimisation measures for medicines with appropriate benefit risk profiles, although cost-effectiveness and other factors, such as frequency/severity of individual ADRs and population differences will still be relevant.

The Emerging Role of the Innate Immune Response in Idiosyncratic Drug Reactions

Idiosyncratic drug reactions (IDRs) range from relatively common, mild reactions to rarer, potentially life-threatening adverse effects that pose significant risks to both human health and successful drug discovery. Most frequently, IDRs target the liver, skin, and blood or bone marrow. Clinical data indicate that most IDRs are mediated by an adaptive immune response against drug-modified proteins, formed when chemically reactive species of a drug bind to self-proteins, making them appear foreign to the immune system. Although much emphasis has been placed on characterizing the clinical presentation of IDRs and noting implicated drugs, limited research has focused on the mechanisms preceding the manifestations of these severe responses. Therefore, we propose that to address the knowledge gap between drug administration and onset of a severe IDR, more research is required to understand IDR-initiating mechanisms; namely, the role of the innate immune response. In this review, we outline the immune processes involved from neoantigen formation to the result of the formation of the immunologic synapse and suggest that this framework be applied to IDR research. Using four drugs associated with severe IDRs as examples (amoxicillin, amodiaquine, clozapine, and nevirapine), we also summarize clinical and animal model data that are supportive of an early innate immune response. Finally, we discuss how understanding the early steps in innate immune activation in the development of an adaptive IDR will be fundamental in risk assessment during drug development. SIGNIFICANCE STATEMENT: Although there is some understanding that certain adaptive immune mechanisms are involved in the development of idiosyncratic drug reactions, the early phase of these immune responses remains largely uncharacterized. The presented framework refocuses the investigation of IDR pathogenesis from severe clinical manifestations to the initiating innate immune mechanisms that, in contrast, may be quite mild or clinically silent. A comprehensive understanding of these early influences on IDR onset is crucial for accurate risk prediction, IDR prevention, and therapeutic intervention.

Baseline plasma KL-6 level predicts adverse outcomes in patients with idiopathic pulmonary fibrosis receiving nintedanib: a retrospective real-world cohort study

Background

Nintedanib is effective for treating idiopathic pulmonary fibrosis (IPF), but some patients may exhibit a suboptimal response and develop on-treatment acute exacerbation (AE-IPF), hepatic injury, or mortality. It remains unclear which patients are at risk for these adverse outcomes.

Methods

We analysed the demographic and clinical data, baseline plasma levels of Krebs von den Lungen-6 (KL-6) and surfactant protein A (SPA), and longitudinal clinical courses of a real-world cohort of IPF patients who received nintedanib ≥ 14 days between March 2017 and December 2020. Cox proportional-hazards regression, subdistribution hazards regression, and sensitivity analyses were performed to investigate the association between baseline predictors and AE-IPF, mortality, and nintedanib-related hepatic injury. The relationship between baseline predictors and pulmonary function decline was determined.

Results

Fifty-seven patients were included, of whom 24 (42%) developed hepatic injury, 20 (35%) had AE-IPF, and 16 (28%) died on-treatment. A baseline plasma KL-6 level ≥ 2.5 ng/mL, and diffusion capacity for carbon monoxide (D_LCO) < 55% predicted, were associated with increased risk of hepatic injury (adjusted hazard ratio [aHR] was 3.46; 95% CI 1.13–10.60; p = 0.029 for KL-6, and 6.05; 95% CI 1.89–19.32; p = 0.002 for D_LCO). Both factors also predicted severe and recurrent hepatic injury. Patients with baseline KL-6 ≥ 2.5 ng/mL also had a higher risk of AE-IPF (aHR 4.52; 95% CI 1.63–12.55; p = 0.004). For on-treatment mortality, baseline KL-6 ≥ 3.5 ng/mL and SPA ≥ 600 pg/mL were significant predictors (aHR 5.39; 95% CI 1.16–24.97; p = 0.031 for KL-6, and aHR 12.28; 95% CI 2.06–73.05; p = 0.006 for SPA). Results from subdistribution hazard regression and sensitivity analyses supported these findings. Patients with elevated baseline plasma KL-6 levels also exhibited a trend towards faster pulmonary function decline.

Conclusions

For patients with IPF who are receiving nintedanib, we have identified baseline predictors, in particular plasma KL-6 levels, for the risk of adverse outcomes. Patients with these predictors may require close monitoring for unfavourable responses during treatment. Our findings also support the prognostic role of molecular markers like KL-6 and may contribute to future formulation of more individualized therapeutic strategies for IPF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01530-6.

Oxidative Stress in Drug-Induced Liver Injury (DILI): From Mechanisms to Biomarkers for Use in Clinical Practice

Idiosyncratic drug-induced liver injury (DILI) is a type of hepatic injury caused by an uncommon drug adverse reaction that can develop to conditions spanning from asymptomatic liver laboratory abnormalities to acute liver failure (ALF) and death. The cellular and molecular mechanisms involved in DILI are poorly understood. Hepatocyte damage can be caused by the metabolic activation of chemically active intermediate metabolites that covalently bind to macromolecules (e.g., proteins, DNA), forming protein adducts-neoantigens-that lead to the generation of oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress, which can eventually lead to cell death. In parallel, damage-associated molecular patterns (DAMPs) stimulate the immune response, whereby inflammasomes play a pivotal role, and neoantigen presentation on specific human leukocyte antigen (HLA) molecules trigger the adaptive immune response. A wide array of antioxidant mechanisms exists to counterbalance the effect of oxidants, including glutathione (GSH), superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX), which are pivotal in detoxification. These get compromised during DILI, triggering an imbalance between oxidants and antioxidants defense systems, generating oxidative stress. As a result of exacerbated oxidative stress, several danger signals, including mitochondrial damage, cell death, and inflammatory markers, and microRNAs (miRNAs) related to extracellular vesicles (EVs) have already been reported as mechanistic biomarkers. Here, the status quo and the future directions in DILI are thoroughly discussed, with a special focus on the role of oxidative stress and the development of new biomarkers.

Drug-induced liver injury: Asia Pacific Association of Study of Liver consensus guidelines

Idiosyncratic drug-induced liver injury mimics acute and chronic liver disease. It is under recognized and underrecognised because of the lack of pathognomonic diagnostic serological markers. Its consequences may vary from being asymptomatic to self-limiting illness to severe liver injury leading to acute liver failure. Its incidence is likely to be more common in Asia than other parts of the world, mainly because of hepatotoxicity resulting from the treatment of tuberculosis disease and the ubiquitous use of traditional and complimentary medicines in Asian countries. This APASL consensus guidelines on DILI is a concise account of the various aspects including current evidence-based information on DILI with special emphasis on DILI due to antituberculosis agents and traditional and complementary medicine use in Asia.

The hepatotoxicity of Polygonum multiflorum: The emerging role of the immune-mediated liver injury

Herbal and dietary supplements (HDS)-induced liver injury has been a great concern all over the world. Polygonum multiflorum Thunb., a well-known Chinese herbal medicine, is recently drawn increasing attention because of its hepatotoxicity. According to the clinical and experimental studies, P. multiflorum-induced liver injury (PM-DILI) is considered to be immune-mediated idiosyncratic liver injury, but the role of immune response and the underlying mechanisms are not completely elucidated. Previous studies focused on the direct toxicity of PM-DILI by using animal models with intrinsic drug-induced liver injury (DILI). However, most epidemiological and clinical evidence demonstrate that PM-DILI is immune-mediated idiosyncratic liver injury. The aim of this review is to assess current epidemiological, clinical and experimental evidence about the possible role of innate and adaptive immunity in the idiosyncratic hepatotoxicity of P. multiflorum. The potential effects of factors associated with immune tolerance, including immune checkpoint molecules and regulatory immune cells on the individual's susceptibility to PM-DILI are also discussed. We conclude by giving our hypothesis of possible immune mechanisms of PM-DILI and providing suggestions for future studies on valuable biomarkers identification and proper immune models establishment.

Multikinase inhibitor-induced liver injury in patients with cancer: A review for clinicians

BACKGROUND

Multikinase inhibitors (MKI) are targeted molecular agents that have revolutionized cancer management. However, there is a paucity of data concerning MKI-related liver injury risk and clinical guidelines for the management of liver toxicity in patients receiving MKI for cancer are scarce.

DESIGN

We conducted a PubMed search of articles in English published from January 2000 to December 2018 related to hepatotoxicity of the 29 FDA-approved MKIs at doses used in clinical practice. The search terms were the international non-proprietary name of each agent cross-referenced with «hepatotoxicity», «hepatitis», «hepatic adverse event», or «liver failure», and «phase II clinical trial», «phase III clinical trial», or «case report».

RESULTS

Following this search, 140 relevant studies and 99 case reports were considered. Although asymptomatic elevation of aminotransferase levels has been frequently observed in MKI clinical trials, clinically significant hepatotoxicity is a rare event. In most cases, the interval between treatment initiation and the onset of liver injury is between one week and two months. Liver toxicity is often hepatocellular and less frequently mixed. Life-threatening MKI-induced hepatic injury has been described, involving fulminant liver failure or death. Starting from existing data, a description of MKI-related liver events, grading of hepatotoxicity risk, and recommendations for management are also given for various MKI molecules.

CONCLUSION

All MKIs can potentially cause liver injury, which is sometimes irreversible. As there is still no strategy available to prevent MKI-related hepatotoxicity, early detection remains crucial. The surveillance of liver function during treatment may help in the early detection of hepatotoxicity. Furthermore, the exclusion of potential causes of hepatic injury is essential to avoid unnecessary MKI withdrawal.

Drug induced liver injury: an update

Drug induced liver injury (DILI) is a relatively rare hepatic condition in response to the use of medications, illegal drugs, herbal products or dietary supplements. It occurs in susceptible individuals through a combination of genetic and environmental risk factors believed to modify drug metabolism and/or excretion leading to a cascade of cellular events, including oxidative stress formation, apoptosis/necrosis, haptenization, immune response activation and a failure to adapt. The resultant liver damage can present with an array of phenotypes, which mimic almost every other liver disorder, and varies in severity from asymptomatic elevation of liver tests to fulminant hepatic failure. Despite recent research efforts specific biomarkers are not still available for routine use in clinical practice, which makes the diagnosis of DILI uncertain and relying on a high degree of awareness of this condition and the exclusion of other causes of liver disease. Diagnostic scales such as the CIOMS/RUCAM can support the causality assessment of a DILI suspicion, but need refinement as some criteria are not evidence-based. Prospective collection of well-vetted DILI cases in established DILI registries has allowed the identification and validation of a number of clinical variables, and to predict a more severe DILI outcome. DILI is also in need of properly designed clinical trials to evaluate the efficacy of new DILI treatments as well as older drugs such as ursodeoxycholic acid traditionally used to ameliorate cholestasis or corticosteroids now widely tried in the oncology field to manage the emergent type of hepatotoxicity related to immune checkpoint inhibitors.

Drug-Induced liver Injury Associated with Severe Cutaneous Hypersensitivity Reactions: A Complex Entity in Need of a Multidisciplinary Approach

Idiosyncratic drug-induced liver injury (DILI) occasionally occurs in the setting of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). This strengthens the proposed immunologic mechanism associated with this adverse reaction. DRESS exhibits the most common association with DILI. SCARs have a wide spectrum of heterogeneous clinical presentations and severity, and genetic predisposition has been identified. In the context of SCARs, DILI present a different clinical picture, ranging from mild injury to acute liver failure. Elucidating the role of DILI in the clinical presentation and outcome of SCARs represents a challenge due to limited information from published studies and the lack of consensus on definitions. The cholestatic and mixed pattern of liver damage typically predominates in the case of DILI associated with SCARs, which is different from DILI without SCARs where hepatocellular is the most common injury pattern. Only a few drugs have been associated with both DILI and SCARs. Is this article, the criteria used for DILI recognition among SCARS have been revised and discussed, along with the drugs most commonly involved in these syndromes as well as the outcome, prognostic factors and the need for a multidisciplinary approach to improve the management of DILI in the context of SCARs.

Signatures in drug-induced liver injury

PURPOSE OF REVIEW

Drug-induced liver injury (DILI) can be induced by a myriad of drugs. Assessing whether the patient has DILI and assessing which drug is the most likely culprit are challenging. There has been too little attention paid to the concept that certain drugs appear to have unique clinical features or 'phenotypes'.

RECENT FINDINGS

Several case series of DILI because of various drugs have been published, and analysis of these case series points to the fact that individual drugs have characteristic DILI signatures. These clinical phenotypes can be characterized by latency, biochemical features (R-value), as well as clinical symptoms and signs. Several drugs, including isoniazid, amoxicillin-clavulanic acid, anabolic steroids, β-interferon and others, have highly unique clinical features. Such unique properties may be able to be used to improve adjudication processes.

SUMMARY

Individual drugs have unique clinical DILI phenotypes or signatures. Furthermore, these may be able to be used to improve adjudication.

Association of ABO blood group and antituberculosis drug-induced liver injury: A case-control study from a Chinese Han population

WHAT IS KNOWN AND OBJECTIVE

Antituberculosis drug-induced liver injury (ATLI) is a serious adverse drug reaction, and its pathogenic mechanism is still largely unknown. Rifampin (RIF) has been reported to cause haemolysis due to the production of drug-dependent antibodies, and haemolysis results in an increased level of free haem, which affects the function of hepatocytes. Blood group determinants can act as specific receptor sites for drug-antibody complexes, causing erythrocyte destruction in the presence of RIF. RIF-induced immune haemolysis may be a potential mechanism for ATLI. Thus, the study aimed to explore the role of ABO blood group systems in Chinese ATLI patients.

METHODS

A 1:4 matched case-control study was conducted among 146 ATLI cases and 584 controls. Multivariable conditional logistic regression and Cox proportional regression were used to estimate the association between ABO blood group and risk of ATLI by odds ratio (OR), hazards ratio (HR) and 95% confidence intervals (CIs), and liver disease history and taking hepatoprotectant were used as covariates.

RESULTS AND DISCUSSION

Patients in the A, B, AB and non-O blood groups had a significantly higher risk of ATLI than those in the O blood group (OR = 1.832, 95% CI: 1.126-2.983, P = .015; OR = 1.751, 95% CI: 1.044-2.937, P = .034; OR = 2.059, 95% CI: 1.077-3.938, P = .029; OR = 1.822, 95% CI: 1.173-2.831, P = .007, respectively). After considering the time of ALTI occurrence, similar results were found in the A, B, AB and non-O blood groups (HR = 1.676, 95% CI: 1.072-2.620, P = .024; HR = 1.620, 95% CI: 1.016-2.584, P = .043; HR = 2.010, 95% CI: 1.130-3.576, P = .018; HR = 1.701, 95% CI: 1.138-2.542, P = .010, respectively). Furthermore, subgroup analysis also detected a significant association between ABO blood group and ATLI in patients taking RIF (P < .05). However, no significant difference was observed in patients not taking RIF (P > .05).

WHAT IS NEW AND CONCLUSION

The present study is the first to evaluate the role of ABO blood group systems in Chinese ATLI cases. Based on the present matched case-control study, the ABO blood group may be associated with susceptibility to ATLI in the Chinese antituberculosis population, especially in patients with blood groups A, B and AB who are taking RIF.

Investigation of Oxidative Stress-Related Candidate Genes as Risk Factors for Drug-Induced Liver Injury due to Co-Amoxiclav

The liver is susceptible to drug toxicity due to its vital role in xenobiotic metabolism and elimination. In addition to human leukocyte antigen (HLA) variants, which were previously determined as risk factors for drug-induced liver injury (DILI) due to co-amoxiclav, other non-HLA genes may contribute to hepatotoxicity risk. In this study, the association between DILI due to co-amoxiclav and several non-HLA genes was investigated. Association of variants in candidate genes (SOD2, GPX1, GSTM1, and GSTT1) with DILI due to various drugs was reported previously in other DILI cohorts. This study examined relevance in a co-amoxiclav-DILI cohort. One hundred sixty-five co-amoxiclav DILI cases were recruited from several European countries by two different studies (DILIGEN and iDILIC). A North-East England population group (n = 334) was used as the control group. PCR assays were used to genotype for the GSTM1 and GSTT1 null alleles with TaqMan SNP genotyping assays used for SOD2 (rs4880) and GPX1 (rs1050450). Fisher's exact test was used to assess differences in significance between cases and controls. None of the studied variants (SOD2 rs4880, GPX1 rs1050450, GSTM1 null allele, and GSTT1 null allele) was significantly associated with co-amoxiclav DILI compared with the control group. No significant differences between cases and controls were seen when combined SOD2/GPX1 genotypes and GST genotypes were considered. Despite the possible functional relevance and the previously reported contribution of the selected genes to DILI, our study failed to confirm associations between the selected genes and liver injury induced by co-amoxiclav.

Genetic Predisposition to Drug-Induced Liver Injury

Identification of genetic predisposition to drug-induced liver injury (DILI) is of paramount importance. Early candidate gene studies have identified various polymorphisms in drug-metabolizing genes that infer increased DILI susceptibility. Few of these have been confirmed in more recent genome-wide association studies, which have identified several specific human leukocyte antigen (HLA) alleles. The low incidence rate of DILI, however, leads to a low positive predictive value for currently identified genetic variations, making them unsuitable for pre-prescription screening. HLA screening incorporated into clinical practice can aid the diagnostic process resulting in enhanced diagnostic accuracy and confidence.

Drug-Induced Liver Injury: Highlights of the Recent Literature

Drug-induced liver injury (DILI), herbal-induced liver injury, and herbal and dietary supplement (HDS)-induced liver injury are an important aspect of drug safety. Knowledge regarding responsible drugs, mechanisms, risk factors, and the diagnostic tools to detect liver injury have continued to grow in the past year. This review highlights what we considered the most significant publications from among more than 1800 articles relating to liver injury from medications, herbal products, and dietary supplements in 2017 and 2018. The US Drug-Induced Liver Injury Network (DILIN) prospective study highlighted several areas of ongoing study, including the potential utility of human leukocyte antigens and microRNAs as DILI risk factors and new data on racial differences, the role of alcohol consumption, factors associated with prognosis, and updates on the clinical signatures of autoimmune DILI, thiopurines, and HDS agents. Novel data were also generated from the Spanish and Latin American DILI registries as well as from Chinese and Korean case series. A few new agents causing DILI were added to the growing list in the past 2 years, including sodium-glucose co-transporter-2 inhibitors, as were new aspects of chemotherapy-associated liver injury. A number of cases reported previously described hepatotoxins confirmed via the Roussel Uclaf Causality Assessment Method (RUCAM; e.g., norethisterone, methylprednisolone, glatiramer acetate) and/or the DILIN method (e.g., celecoxib, dimethyl fumarate). Additionally, much work centered on elucidating the pathophysiology of DILI, including the importance of bile salt export pumps and immune-mediated mechanisms. Finally, it must be noted that, while hundreds of new studies described DILI in 2017-2018, the quality of such reports must always be addressed. Björnsson reminds us to remain very critical of the data when addressing the future utility of a study, which is why it is so important to adhere to a standardized method such as RUCAM when determining DILI causality. While drug-induced hepatotoxicity remains a diagnosis of exclusion, the diverse array of publications that appeared in 2017 and 2018 provided important advances in our understanding of DILI, paving the way for our improved ability to make a more definitive diagnosis and risk assessment.

Research advances in the association of drug-induced liver injury with polymorphisms in human leukocyte antigen

Drug-induced liver injury is an important adverse drug reaction. Due to the lack of specificity in clinical symptoms and pathological features, there are still no reliable diagnostic biomarkers, so drug-induced liver injury is a diagnosis of exclusion. The article reviews the relevant advances in the association between novel human leukocyte antigen gene polymorphisms and drug-induced liver injury in order to identify potential biomarkers and provide a new method for the prediction and diagnosis of drug-induced liver injury. Henceforth, while studying the association between them, it will also need that the large sample and prospective studies to gain supporting evidence to implement translational application, so as to improve the safety and effectiveness of medication and achieve individualized treatment.

Definition of the Chemical and Immunological Signals Involved in Drug-Induced Liver Injury

Idiosyncratic drug-induced liver injury (iDILI), which is rare and often recognized only late in drug development, poses a major public health concern and impediment to drug development due to its high rate of morbidity and mortality. The mechanisms of DILI are not completely understood; both non-immune- and immune-mediated mechanisms have been proposed. Non-immune-mediated mechanisms including direct damage to hepatocytes, mitochondrial toxicity, interference with transporters, and alteration of bile ducts are well-known to be associated with drugs such as acetaminophen and diclofenac; whereas immune-mediated mechanisms involving activation of both adaptive and innate immune cells and the interactions of these cells with parenchymal cells have been proposed. The chemical signals involved in activation of both innate and adaptive immune responses are discussed with respect to recent scientific advances. In addition, the immunological signals including cytokine and chemokines that are involved in promoting liver injury are also reviewed. Finally, we discuss how liver tolerance and regeneration can have profound impact on the pathogenesis of iDILI. Continuous research in developing in vitro systems incorporating immune cells with liver cells and animal models with impaired liver tolerance will provide an opportunity for improved prediction and prevention of immune-mediated iDILI.

Strategies for Early Prediction and Timely Recognition of Drug-Induced Liver Injury: The Case of Cyclin-Dependent Kinase 4/6 Inhibitors

The idiosyncratic nature of drug-induced liver injury (DILI) represents a current challenge for drug developers, regulators and clinicians. The myriad of agents (including medications, herbals, and dietary supplements) with recognized DILI potential not only strengthens the importance of the post-marketing phase, when urgent withdrawal sometimes occurs for rare unanticipated liver toxicity, but also shows the imperfect predictivity of pre-clinical models and the lack of validated biomarkers beyond traditional, non-specific liver function tests. After briefly reviewing proposed key mechanisms of DILI, we will focus on drug-related risk factors (physiochemical and pharmacokinetic properties) recently proposed as predictors of DILI and use cyclin-dependent kinase 4/6 inhibitors, relatively novel oral anticancer medications approved for breast cancer, as a case study to discuss the feasibility of early detection of DILI signals during drug development: published data from pivotal clinical trials, unpublished post-marketing reports of liver adverse events, and pharmacokinetic properties will be used to provide a comparative evaluation of their liver safety and gain insight into drug-related risk factors likely to explain the observed differences.

Early ALT response to corticosteroid treatment distinguishes idiosyncratic drug-induced liver injury from autoimmune hepatitis

BACKGROUND

Drug-induced liver injury (DILI) and idiopathic autoimmune hepatitis (AIH) are competing diagnoses in patients with acute liver injury (ALI) and drug intake. In absence of unequivocal markers, scores like RUCAM and AIH are used to distinguish both entities. However, in some cases the diagnosis remains ambiguous. Our aim was to identify a simple parameter to discriminate DILI and AIH shortly after starting corticosteroid treatment.

METHODS

For the current analysis, 44 patients with ALI who took at least one drug and who received corticosteroids were included and comprised 22 DILI and 22 AIH cases. Scores of AIH and RUCAM were calculated at initial presentation, the final diagnosis was made from analysing the course of disease. Changes in the serum alanine aminotransferase (ALT) concentrations after starting corticosteroid treatment were determined and compared between the DILI and AIH groups.

RESULTS

Fifty-nine per cent of patients (n = 26) were correctly classified at presentation by AIH score and RUCAM respectively. However, in one-third (n = 13) of the 44 patients, results were inconclusive and five other patients were misclassified. The decrease in ALT levels 1 week after the initiation of steroid therapy was significantly more pronounced in patients with the final diagnosis of DILI than in AIH patients (accuracy 77%). This difference was also observed in the 18 initially misclassified or inconclusive cases (accuracy 83%).

CONCLUSION

Short-term response of ALT to corticosteroid therapy helps to differentiate DILI and AIH. This finding may be helpful in treatment decision for patients with inconclusive diagnostic scores.

Liver dysfunction induced by Levothyroxine Sodium Tablets (Euthyrox®) in a hypothyroid patient with Hashimoto's thyroiditis: case report and literature review

A 49-year-old woman with hypothyroidism developed liver dysfunction after increasing dose of levothyroxine (L-T4) (Euthyrox^®) from 25 μg to 50 μg. Viral hepatitis, autoimmune hepatitis and non-alcoholic steatohepatitis (NASH) were ruled out with examinations. She had no concurrent medication and had no history of infectious, chronic or any other autoimmune diseases. After cessation of Levothyroxine Sodium Tablets (Euthyrox^®), liver enzymes gradually returned to normal. She was diagnosed levothyroxine-induced liver injury, based on criteria proposed in "Diagnosis and treatment guideline on drug-induced liver injury" issued by the Chinese Medical Association (2015). As an alternative 25 μg qod of Levothyroxine Sodium Tablets (Letrox^®) was tried and increased gradually up to 75 μg daily. Since then liver enzymes have remained within normal range. The main difference of additive for both tablets is whether it contains lactose or not: Euthyrox^® contains lactose which caused no liver injury, thus excluding the possibility that an additive of Euthyrox^® contributed to liver injury. The relatively quicker and larger replacement with synthetic T4 for hypothyroidism inducing transient thyrotoxicosis was suspected, although thyroid function was normal. Immune-mediated drug-induced liver injury (DILI) was also not excluded. This is a rare case of drug-induced liver injury due to levothyroxine tablets. It reminded us that when replacement with synthetic T4 for hypothyroidism is done, smaller-dose initiation and slower-speed increase may be useful for treatment of cases similar to genetically susceptible individuals.

Drug-induced liver injury

Drug-induced liver injury (DILI) is an adverse reaction to drugs or other xenobiotics that occurs either as a predictable event when an individual is exposed to toxic doses of some compounds or as an unpredictable event with many drugs in common use. Drugs can be harmful to the liver in susceptible individuals owing to genetic and environmental risk factors. These risk factors modify hepatic metabolism and excretion of the DILI-causative agent leading to cellular stress, cell death, activation of an adaptive immune response and a failure to adapt, with progression to overt liver injury. Idiosyncratic DILI is a relative rare hepatic disorder but can be severe and, in some cases, fatal, presenting with a variety of phenotypes, which mimic other hepatic diseases. The diagnosis of DILI relies on the exclusion of other aetiologies of liver disease as specific biomarkers are still lacking. Clinical scales such as CIOMS/RUCAM can support the diagnostic process but need refinement. A number of clinical variables, validated in prospective cohorts, can be used to predict a more severe DILI outcome. Although no pharmacological therapy has been adequately tested in randomized clinical trials, corticosteroids can be useful, particularly in the emergent form of DILI related to immune-checkpoint inhibitors in patients with cancer.

HLA-B*35:01 Allele Is a Potential Biomarker for Predicting Polygonum multiflorum-Induced Liver Injury in Humans

Polygonum multiflorum (PM) is a well-known Chinese herbal medicine that has been reported to induce inflammation-associated idiosyncratic liver injury. This study aimed to identify the genetic basis of susceptibility to PM-drug-induced liver injury (PM-DILI) and to develop biological markers for predicting the risk of PM-DILI in humans. The major histocompatibility complex (MHC) regions of 11 patients with PM-DILI were sequenced, and all human leukocyte antigen (HLA)-type frequencies were compared to the Han-MHC database. An independent replication study that included 15 patients with PM-DILI, 33 patients with other DILI, and 99 population controls was performed to validate the candidate allele by HLA-B PCR sequence-based typing. A prospective cohort study that included 72 outpatients receiving PM for 4 weeks was designed to determine the influence of the risk allele on PM-DILI. In the pilot study, the frequency of HLA-B*35:01 was 45.4% in PM-DILI patients compared with 2.7% in the Han Chinese population (odds ratio [OR], 30.4; 95% confidence interval [CI], 11.7-77.8; P = 1.9 × 10^-10 ). In the independent replication study and combined analyses, a logistic regression model confirmed that HLA-B*35:01 is a high-risk allele of PM-DILI (PM-DILI versus other DILI, OR, 86.5; 95% CI, 14.2-527.8, P = 1.0 × 10^-6 ; and PM-DILI versus population controls, OR, 143.9; 95% CI, 30.1-687.5, P = 4.8 × 10^-10 ). In the prospective cohort study, an asymptomatic increase in transaminase levels was diagnosed in 6 patients, representing a significantly higher incidence (relative risk, 8.0; 95% CI, 1.9-33.2; P < 0.02) in the HLA-B*35:01 carriers (37.5%) than in the noncarriers (4.7%). Conclusion: The HLA-B*35:01 allele is a genetic risk factor for PM-DILI and a potential biomarker for predicting PM-DILI in humans.

Hepatotoxicity Due to Azole Antimycotic Agents in a HLA B*35:02-Positive Patient

We will present a 42-year-old woman with acute myeloid leukemia and pulmonary aspergillosis. She was treated with several antifungal agents, including three triazoles. Voriconazole, posaconazole, and isavuconazole all led to hepatocellular liver injury. Voriconazole administration led to a peak alanine aminotransferase (ALT) value of 1,793 U/L (normal range, 9–59 U/L). After posaconazole and isavuconazole treatment, ALT rose over 500 U/L. The typical course of events, exclusion of differential diagnoses, and normalization of the liver function tests (LFTs) after stopping the triazoles were highly suspicious for a drug-induced liver injury (DILI). Interestingly, our patient carries a rare HLA B allele (HLA B*35:02), which occurs in less than 1% of the population and is known to be associated with minocycline-induced liver injury. Over the course of 4 months, the patient received two induction chemotherapies and afterward underwent a successful allogenic hematopoietic stem cell transplantation. Her liver function recovered rapidly and favorable clinical findings concerning the aspergillosis led to a de-escalation of the antifungal treatment to prophylactic dose fluconazole. Delayed hepatotoxicity suggested a dose dependency and a cumulative effect. The question of a common pathophysiology and a cross-toxicity was raised. At the present time, only a few case reports describe cross-toxicity or its absence after rechallenge with different azoles. The pathophysiology is not well understood. Ketoconazole was found to impair rat mitochondrial function in vitro. Further investigations showed cell membrane toxicity and ATP depletion in isolated human liver cancer cells. Our case report suggests a cross-toxicity, dose-dependency, and a possible genetic predisposition of triazole-induced liver injury.

EASL Clinical Practice Guidelines: Drug-induced liver injury

Idiosyncratic (unpredictable) drug-induced liver injury is one of the most challenging liver disorders faced by hepatologists, because of the myriad of drugs used in clinical practice, available herbs and dietary supplements with hepatotoxic potential, the ability of the condition to present with a variety of clinical and pathological phenotypes and the current absence of specific biomarkers. This makes the diagnosis of drug-induced liver injury an uncertain process, requiring a high degree of awareness of the condition and the careful exclusion of alternative aetiologies of liver disease. Idiosyncratic hepatotoxicity can be severe, leading to a particularly serious variety of acute liver failure for which no effective therapy has yet been developed. These Clinical Practice Guidelines summarize the available evidence on risk factors, diagnosis, management and risk minimization strategies for drug-induced liver jury.

Liver function biomarkers disorder is associated with exposure to perfluoroalkyl acids in adults: Isomers of C8 Health Project in China

Exposure to chemicals may affect liver enzyme to increase the risk of liver diseases. Perfluoroalkyl acids (PFAAs) are one kind of persistent organic pollutants with hepatotoxic effect in organism. However, data is scarce to characterize the hepatotoxic effects of specific structural PFAA isomers in general population. To address this data gap, we evaluated the association between serum PFAAs concentration and liver function biomarkers in the Isomers of C8 Health Project in China. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to measure 18 serum PFAAs, except for linear and branched isomers of PFOA/PFOS, nine perfluorinated carboxylic acids (PFCAs) and two perfluorinated sulfonic acids (PFSAs) were also included, in 1605 adult residents of Shenyang, China. Values for nine serum liver function biomarkers were determined by full-automatic blood biochemical analyzer. Linear regression was used to evaluate associations between PFAAs and continuous liver function biomarkers and logistic regression to assess markers dichotomized per clinical reference intervals. Results indicated that serum PFAAs concentrations were associated with liver biomarker levels suggestive of hepatotoxicity, especially for liver cell injury. For example, a 1 ln-unit increase in total- perfluorooctanoic acid (PFOA) exposure was associated with a 7.4% [95% confidence interval (CI): 3.9%, 11.0%] higher alanine aminotransferase (ALT) level in serum. Interestingly, we observed association between branched PFAA isomers and liver biomarkers. For example, one ln-unit increase in branched perfluorooctane sulfonate (PFOS) isomers exposure was associated with a 4.3% increase in ALT level (95% CI: 1.2%, 7.4%) and a 33.0% increased odds of having abnormal ALT (95% CI: 5.0%, 67.0%). Also, we found that PFNA had positive association with ALT [(6.2%, 95% CI: 3.1%, 9.4%) and AST levels (2.5%, 95% CI: 0.5%, 4.5%)]. Logistic regression results showed that PFPeA, PFHxA, PFNA, PFDoDA, PFTrDA and PFTeDA had statistically association with abnormal prealbumin. Conclusively, our results support previous studies showing association between PFAAs exposure and liver function biomarkers. We found new evidence that branched PFAAs isomer exposure is associated with the risk of clinically relevant hepatocellular dysfunction.

Next-Generation Sequencing of PTGS Genes Reveals an Increased Frequency of Non-synonymous Variants Among Patients With NSAID-Induced Liver Injury

Purpose: The etiopathogenesis of drug-induced liver injury (DILI) is still far from being elucidated. This study aims to the study of genetic variations in DILI, related to the drug target, and specifically in the genes coding for the cyclooxygenase enzymes.

Methods: By using Next-generation Sequencing we analyzed the genes coding for COX enzymes (PTGS1 and PTGS2) in 113 individuals, 13 of which were patients with DILI caused by COX-inhibitors.

Results: The key findings of the study are the increased frequency, among DILI patients, of SNPs causing alterations in transcription factor binding sites and non-synonymous PTGS gene variants, as compared to control subjects. Moreover, the association with non-synonymous SNPs was exclusive of DILI patients with late-onset (50 days or more) Pc < 0.001 as compared to DILI patients with early onset, or with control subjects.

Conclusions: Our findings suggest an interaction of long-term exposure to COX inhibitors combined with functional variants of the COX enzymes in the risk of developing DILI. This is a novel observation that might have been overlooked by previous genetic studies on DILI because of the limited coverage of PTGS genes in exome chips.