Flucloxacillin-induced Liver Research Articles

Identification of flucloxacillin-modified hepatocellular proteins: implications in flucloxacillin-induced liver injury.

Flucloxacillin is a β-lactam antibiotic associated with a high incidence of drug-induced liver injury. Although expression of HLA-B*57:01 is associated with increased susceptibility, little is known of the pathological mechanisms involved in the induction of the clinical phenotype. Irreversible protein modification is suspected to drive the reaction through the provision of flucloxacillin-modified peptides that are presented to T-cells by the protein encoded by the risk allele. In this study, we have shown that flucloxacillin binds to multiple proteins within human primary hepatocytes, including major hepatocellular proteins (hemoglobin and albumin) and mitochondrial proteins. Inhibition of membrane transporters multidrug resistance-associated protein 2 (MRP2) and P-glycoprotein (P-gp) appeared to reduce the levels of covalent binding. A diverse range of proteins with different functions was found to be targeted by flucloxacillin, including adaptor proteins (14-3-3), proteins with catalytic activities (liver carboxylesterase 1, tRNA-splicing endonuclease subunit Sen2, All-trans-retinol dehydrogenase ADH1B, Glutamate dehydrogenase 1 mitochondrial, Carbamoyl-phosphate synthase [ammonia] mitochondrial), and transporters (hemoglobin, albumin, and UTP-glucose-1-phosphate uridylyltransferase). These flucloxacillin-modified intracellular proteins could provide a potential source of neoantigens for HLA-B*57:01 presentation by hepatocytes. More importantly, covalent binding to critical cellular proteins could be the molecular initiating events that lead to flucloxacillin-induced cholestasis Data are available via ProteomeXchange with identifier PXD038581.

Cell Membrane Transporters Facilitate the Accumulation of Hepatocellular Flucloxacillin Protein Adducts: Implication in Flucloxacillin-Induced Liver Injury.

Flucloxacillin is a β-lactam antibiotic associated with a high incidence of drug-induced liver reactions. Although expression of HLA-B*57:01 increases susceptibility, little is known about the pathological mechanisms involved in the induction of the clinical phenotype. Irreversible protein modification is suspected to drive the reaction through the presentation of flucloxacillin-modified peptides by the risk allele. In this study, the binding of flucloxacillin to proteins of liver-like cells was characterized. Flucloxacillin was shown to bind to proteins localized in bile canaliculi regions, coinciding with the site of clinical disease. The localization of flucloxacillin was mediated primarily by the membrane transporter multidrug resistance-associated protein 2. Modification of multiple proteins by flucloxacillin in bile canaliculi regions may provide a potential local source of neo-antigens for HLA presentation in the liver.

Quantification of the risk of liver injury associated with flucloxacillin: a UK population-based cohort study.

BackgroundFlucloxacillin is an established cause of liver injury. Despite this, there are a lack of published data on both the strength of association after adjusting for potential confounders, and the absolute incidence among different subgroups of patients.ObjectivesTo assess the relative and absolute risks of liver injury following exposure to flucloxacillin and identify subgroups at potentially increased risk.MethodsA cohort study between 1 January 2000 and 1 January 2012 using the UK Clinical Practice Research Datalink, including 1 046 699 people with a first prescription for flucloxacillin (861 962) or oxytetracycline (184 737). Absolute risks of experiencing both symptom-defined (jaundice) and laboratory-confirmed liver injury within 1–45 and 46–90 days of antibiotic initiation were estimated. Multivariable logistic regression was used to estimate 1–45 day relative effects.ResultsThere were 183 symptom-defined cases (160 prescribed flucloxacillin) and 108 laboratory-confirmed cases (102 flucloxacillin). The 1–45 day adjusted risk ratio for laboratory-confirmed injury was 5.22 (95% CI 1.64–16.62) comparing flucloxacillin with oxytetracycline use. The 1–45 day risk of laboratory-confirmed liver injury was 8.47 per 100 000 people prescribed flucloxacillin (95% CI 6.64–10.65). People who received consecutive flucloxacillin prescriptions had a 1–45 day risk of jaundice of 39.00 per 100 000 (95% CI 26.85–54.77), while those aged >70 receiving consecutive prescriptions had a risk of 110.57 per 100 000 (95% CI 70.86–164.48).ConclusionsThe short-term risk of laboratory-confirmed liver injury was >5-fold higher after a flucloxacillin prescription than an oxytetracycline prescription. The risk of flucloxacillin-induced liver injury is particularly high within those aged >70 and those who receive multiple flucloxacillin prescriptions. The stratified risk estimates from this study could help guide clinical care.

Bile Nephropathy in Flucloxacillin-Induced Cholestatic Liver Dysfunction.

Kidney injury in the context of cholestatic liver dysfunction is not uncommon; this has been historically referred to as cholemic nephrosis implying a direct deleterious renal effect of cholemia. However, scepticism about the exact role that bile and its constituents play in this injury has led to the disappearance of the term. We describe a case of severe AKI due to bile nephropathy with bile casts in flucloxacillin-induced liver dysfunction. We also discuss the recent literature reviving the concept of bile nephropathy.

Promiscuous T-cell responses to drugs and drug-haptens

Promiscuous T-cell responses to drugs and drug-haptens

Genome-wide Studies in Pharmacogenomics: Harnessing the Power of Extreme Phenotypes

Baldwin et al. on paclitaxel-induced sensory peripheral neuropathy [5], and Brown et al. on temozolomideassociated cytotoxicity [6] have advanced our understanding of DNA sequence variations and drug response, and several pharmaco genomic tests are on their way to clinical practice [7]. The studies on toxic drug reactions in particular have extra power compared with typical GWAS. For example, the study by Daly et al. on flucloxacillin-induced liver injury, an extreme and rare drug response phenotype, included only 51 affected individuals and 282 controls, yet it reported the unprecedented odds risk ratio of 80.6 (p = 8.7 × 10 for carriers of HLA-B*5701) [4], while typical GWAS odds risk ratios are below 2. We propose that the extreme phenotypes approach should be prioritized for genomewide pharmacogenomic studies, including those exploring genomic biomarkers for treatment efficacy as an alternative to enrolling very large random patient cohorts. This is based on both the likelihood of an enrichment for genomic signal due to the ‘Mendelian’ nature of the pheno type, the favorable study costs and reduced ‘noise’ arising from inaccurate pheno typing. Taken together, it seems far more effective to compare genome-wide data between ‘excellent drug responders’ versus nonresponders, compared with analyzing such data from huge patient cohorts representing a large spectrum of intermediate responders. The superior power of the extreme phenotype approach is exemplified by the recent study of Edmond et al., who identified DCTN4 as a modifier of chronic infection in cystic fibrosis among 91 individuals whose exomes were sequenced [8]. As a further example, expression levels of CHL1 were recently reported as Four years ago this journal featured a theme issue on genome-wide association studies (GWAS) in pharmacogenomics. In our accompanying editorial we noted that “relatively few GWAS on drug response were so far published compared with the large numbers of disease risk GWAS” and called upon the pharmacogenomics research community to apply this powerful, hypothesis-free research approach for improving knowledge on drug safety and efficacy [1]. Our call seems to have been timely, as the past few years have witnessed an increase in pharmacogenomics-oriented genome-wide studies. Among PubMed-listed pharmacogenomics-related manuscripts, the fraction of those mentioning both ‘pharmacogenomics’ and ‘genome-wide’ as keywords have risen fourfold over the past few years, from 2.1% in 2006 to nearly 9% of total manuscripts published between 2009 and 2012 (Table 1). However, as in past years, only a tiny fraction (under 2%) of published genome-wide studies (in all areas) are concerned with pharmacogenomics (Table 1), a disappointingly low figure considering the huge societal burden of adverse drug events and ineffective therapeutics [2].

Human Leukocyte Antigen (HLA)-B*57:01-Restricted Activation of Drug-Specific T cells Provides the Immunological Basis for Flucloxacillin-Induced Liver Injury

The role of the adaptive immune system in adverse drug reactions that target the liver has not been defined. For flucloxacillin, a delay in the reaction onset and identification of human leukocyte antigen (HLA)-B*57:01 as a susceptibility factor are indicative of an immune pathogenesis. Thus, we characterize flucloxacillin-responsive CD4+ and CD8+ T cells from patients with liver injury and show that naive CD45RA+CD8+ T cells from volunteers expressing HLA-B*57:01 are activated with flucloxacillin when dendritic cells present the drug antigen. T-cell clones expressing CCR4 and CCR9 migrated toward CCL17 and CCL 25, and secreted interferon-gamma (IFN-γ), T helper (Th)2 cytokines, perforin, granzyme B, and FasL following drug stimulation. Flucloxacillin bound covalently to selective lysine residues on albumin in a time-dependent manner and the level of binding correlated directly with the stimulation of clones. Activation of CD8+ clones with flucloxacillin was processing-dependent and restricted by HLA-B*57:01 and the closely related HLA-B*58:01. Clones displayed additional reactivity against β-lactam antibiotics including oxacillin, cloxacillin, and dicloxacillin, but not abacavir or nitroso sulfamethoxazole. This work defines the immune basis for flucloxacillin-induced liver injury and links the genetic association to the iatrogenic disease.

The risk of azathioprine-induced pancreatitis depends on genetic variants in the HLA gene region

IntroductionAcute pancreatitis occurs in around 2% of inflammatory bowel disease patients exposed to azathioprine or 6-mercaptopurine and is an important limiting toxicity of these thiopurine antimetabolites. Factors determining the risk...

Drug-induced liver injury: a clinical update

To gather new and important data published on idiosyncratic drug-induced liver injury (DILI) over the past 2 years in the peer-reviewed literature. Clinical studies focusing on mechanisms of injury, clinical evaluation and prognosis will be reviewed. The most common drugs leading to DILI in the United States are antibiotics, central nervous system agents, herbal/dietary supplements and immunomodulatory agents. Hepatocellular type of DILI is more common in younger patients, whereas cholestatic pattern increases with older age. Certain human leukocyte antigen genotype increases the likelihood of flucloxacillin-induced liver injury. Idiosyncratic DILI was shown to have an important dose-dependency and drugs with extensive hepatic metabolism are associated with higher frequency of DILI. Chronic DILI may occur, but development of clinically important liver injury after severe DILI is rare. N-acetylcysteine seems to be beneficial for patients with acute liver failure caused by medications or herbal agents.

A Role for the Pregnane X Receptor in Flucloxacillin-Induced Liver Injury

Drug-induced liver injury (DILI) due to flucloxacillin is a rare but serious complication of treatment. There is some evidence that flucloxacillin is a human pregnane X receptor (PXR) agonist. This study was designed to investigate the relevance of PXR to flucloxacillin toxicity and to identify genes changing in expression in response to flucloxacillin. Changes in gene expression in human hepatocytes after treatment with 500 microM flucloxacillin for 72 hours were examined by expression microarray analysis. The ability of flucloxacillin to act as a PXR agonist was investigated with reporter gene experiments. Flucloxacillin DILI cases (n = 51), drug-exposed controls without toxicity (n = 64), and community controls (n = 90) were genotyped for three common PXR polymorphisms. Luciferase reporter assays were used to assess the significance of a promoter region PXR polymorphism. Seventy-two probe sets representing 50 different genes showed significant changes in expression of 1.2-fold or higher. Most genes showing changes greater than 3-fold were known to be rifampicin-responsive, and this suggested a PXR-dependent mode of regulation. Using a luciferase-everted repeat separated by 6 base pairs element construct, we confirmed that flucloxacillin was a PXR agonist. We found a difference in the distribution of a PXR polymorphism (rs3814055; C-25385T) between flucloxacillin DILI cases and controls with the CC genotype associated with an increased risk of disease (odds ratio = 3.37, 95% confidence interval = 1.55-7.30, P = 0.0023). Reporter gene experiments showed lower promoter activity for the C allele than the T allele. Flucloxacillin is a PXR agonist at pharmacologically relevant concentrations, and a functionally significant upstream PXR polymorphism is a risk factor for flucloxacillin-induced DILI.

Relevance of PXR to Flucloxacillin-induced Liver Injury

Relevance of PXR to Flucloxacillin-induced Liver Injury

Flucloxacillin-induced aplastic anaemia and liver failure

Flucloxacillin is a commonly prescribed semisynthetic penicillinase-resistant penicillin primarily used for the treatment of cutaneous staphylococcal infections. It is well-recognized that flucloxacillin may occasionally result in fatal hepatic injury. We report the case of a 40-year-old woman who developed fulminant hepatic failure and aplastic anaemia following a course of oral flucloxacillin. At the time of transplantation the patient was severely neutropenic. Post-transplant, the patient received single donor leucocyte transfusions, which resulted in a dramatic increase in neutrophil count. The patient was discharged from hospital after 120 days with normal liver function and recovered bone marrow. In this report, we discuss the care of patients with aplastic anaemia in the peritransplant setting.

Antibiotic-associated acute vanishing bile duct syndrome: A pattern associated with severe, prolonged, intrahepatic cholestasis

We report cases of amoxycillin- and flucloxacillin-induced liver damage associated with an acute vanishing bile duct syndrome. Ductopenia was present at the time of first liver biopsy, 3 weeks and 3 months after administration of the two drugs, respectively. Ductopenia apparently occurred as the primary lesion, with no evidence of accompanying portal tract inflammation. Subsequent biopsies showed a persistent paucity of ducts, accompanied by increasing features of chronic cholestasis. Biochemical dysfunction persists at 2 year's follow-up and late prognosis remains guarded.

Predicting mortality from cancer of the uterine cervix from 1991-2001.

The aim was to provide benchmarks by which to judge the success of behaviour change and the cervical cancer screening programme in England and Wales in reducing mortality from this disease over the next decade. Log-linear models and cervical cancer mortality data by age and marital status from 1959-88 were used to predict future mortality in England and Wales. Recombining "predicted" deaths in marital status groups for 1984-88 gave a closer agreement to total mortality observed in those years than predictions based on past trends from 1959-83 among women of all statuses combined. Mortality for 1989-2003 was then predicted, using the data for 1959-1988. The reaggregated marital status forecasts of mortality provide an upper boundary which future observed mortality should not cross if primary and secondary prevention measures are working effectively. The method allows swift comparison of observation with expectation and therefore the rapid evaluation of the overall performance of preventive strategies.

Flucloxacillin-induced Cholestatic Liver Damage

AbstractTwo female patients (75 and 68 yr old) developed jaundice 4 and 7 weeks respectively after treatment with flucloxacillin. Liver biopsies showed intrahepatic cholestasis. After cessation of the drug, the liver tests became normal.