Guruprasad P. Aithal

HLA-B*5701 genotype is a major determinant of drug-induced liver injury due to flucloxacillin

Drug-induced liver injury (DILI) is an important cause of serious liver disease. The antimicrobial agent flucloxacillin is a common cause of DILI, but the genetic basis for susceptibility remains unclear. We conducted a genome-wide association (GWA) study using 866,399 markers in 51 cases of flucloxacillin DILI and 282 controls matched for sex and ancestry. The GWA showed an association peak in the major histocompatibility complex (MHC) region with the strongest association (P = 8.7 × 10−33) seen for rs2395029[G], a marker in complete linkage disequilibrium (LD) with HLA-B*5701. Further MHC genotyping, which included 64 flucloxacillin-tolerant controls, confirmed the association with HLA-B*5701 (OR = 80.6, P = 9.0 × 10−19). The association was replicated in a second cohort of 23 cases. In HLA-B*5701 carrier cases, rs10937275 in ST6GAL1 on chromosome 3 also showed genome-wide significance (OR = 4.1, P = 1.4 × 10−8). These findings provide new insights into the mechanism of flucloxacillin DILI and have the potential to substantially improve diagnosis of this serious disease.

Noninvasive markers of fibrosis in nonalcoholic fatty liver disease: Validating the European Liver Fibrosis Panel and exploring simple markers

The detection of fibrosis within nonalcoholic fatty liver disease (NAFLD) is important for ascertaining prognosis and the stratification of patients for emerging therapeutic intervention. We validated the Original European Liver Fibrosis panel (OELF) and a simplified algorithm not containing age, the Enhanced Liver fibrosis panel (ELF), in an independent cohort of patients with NAFLD. Furthermore, we explored whether the addition of simple markers to the existing panel test could improve diagnostic performance. One hundred ninety‐six consecutively recruited patients from 2 centers were included in the validation study. The diagnostic accuracy of the discriminant scores of the ELF panel, simple markers, and a combined panel were compared using receiver operator curves, predictive values, and a clinical utility model. The ELF panel had an area under the curve (AUC) of 0.90 for distinguishing severe fibrosis, 0.82 for moderate fibrosis, and 0.76 for no fibrosis. Simplification of the algorithm by removing age did not alter diagnostic performance. Addition of simple markers to the panel improved diagnostic performance with AUCs of 0.98, 0.93, and 0.84 for the detection of severe fibrosis, moderate fibrosis, and no fibrosis, respectively. The clinical utility model showed that 82% and 88% of liver biopsies could be potentially avoided for the diagnosis of severe fibrosis using ELF and the combined panel, respectively. The ELF panel has good diagnostic accuracy in an independent validation cohort of patients with NAFLD. The addition of established simple markers augments the diagnostic performance across different stages of fibrosis, which will potentially allow superior stratification of patients with NAFLD for emerging therapeutic strategies. (HEPATOLOGY 2007.)

Randomized, Placebo-Controlled Trial of Pioglitazone in Nondiabetic Subjects With Nonalcoholic Steatohepatitis

BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease for which there is limited therapy available. Insulin sensitizing, anti-inflammatory, and antifibrotic properties of thiazolidinediones support their use in treating NASH. We have evaluated pioglitazone in the treatment of nondiabetic patients with NASH. METHODS We randomized 74 nondiabetic patients (45 men; median age, 54 y) with histologically proven NASH to 12 months of standard diet, exercise, and either placebo or pioglitazone (30 mg/day). Sixty-one patients (30 placebo, 31 pioglitazone) had liver biopsies both at the beginning and the end of the study. RESULTS Compared with placebo, pioglitazone therapy was associated with an increase in weight (mean change, -0.55 vs +2.77 kg; P = .04) and a reduction in glucose (+0.4 vs -0.1 mmol/L; P = .02), HbA1c (+0.16% vs -0.18%; P = .006), insulin C peptide level (+42 vs -78 pmol/L; P = .02), alanine aminotransferase level (-10.9 vs -36.2 u/L; P = .009), gamma-glutamyltransferase level (-9.4 vs -41.2 u/L; P = .002), and ferritin (-11.3 vs -90.5 microg/L; P = .01). Histologic features including hepatocellular injury (P = .005), Mallory-Denk bodies (P = .004), and fibrosis (P = .05) were reduced in patients treated with pioglitazone compared with those in the placebo group. CONCLUSIONS Pioglitazone therapy over a 12-month period in nondiabetic subjects with NASH resulted in improvements in metabolic and histologic parameters, most notably liver injury and fibrosis. Larger extended trials are justified to assess the long-term efficacy of pioglitazone in this patient group.

Case Definition and Phenotype Standardization in Drug-Induced Liver Injury

Drug‐induced liver injury (DILI) is the most frequent reason cited for the withdrawal of approved drugs from the market and accounts for up to 15% of the cases of acute liver failure. Investigators around the globe have begun to identify and study patients with DILI; several large registries and tissue banks are being established. In order to gain the maximum scientific benefit from these efforts, the definitions and terminology related to the clinical phenotypes of DILI must be harmonized. For this purpose, an international DILI Expert Working Group of clinicians and scientists reviewed current DILI terminology and diagnostic criteria so as to develop more uniform criteria that would define and characterize the spectrum of clinical syndromes that constitute DILI. Consensus was established with respect to the threshold criteria for definition of a case as being DILI, the pattern of liver injury, causality assessment, severity, and chronicity. Consensus was also reached on approaches to characterizing DILI in the setting of chronic liver diseases, including autoimmune hepatitis (AIH).

Susceptibility to Amoxicillin-Clavulanate-Induced Liver Injury is Influenced by Multiple HLA Class I and II Alleles

BACKGROUND & AIMS Drug-induced liver injury (DILI), especially from antimicrobial agents, is an important cause of serious liver disease. Amoxicillin-clavulanate (AC) is a leading cause of idiosyncratic DILI, but little is understood about genetic susceptibility to this adverse reaction. METHODS We performed a genome-wide association study using 822,927 single nucleotide polymorphism (SNP) markers from 201 White European and US cases of DILI following AC administration (AC-DILI) and 532 population controls, matched for genetic background. RESULTS AC-DILI was associated with many loci in the major histocompatibility complex. The strongest effect was with an HLA class II SNP (rs9274407, P=4.8×10(-14)), which correlated with rs3135388, a tag SNP of HLA-DRB1*1501-DQB1*0602 that was previously associated with AC-DILI. Conditioned on rs3135388, rs9274407 is still significant (P=1.1×10(-4)). An independent association was observed in the class I region (rs2523822, P=1.8×10(-10)), related to HLA-A*0201. The most significant class I and II SNPs showed statistical interaction (P=.0015). High-resolution HLA genotyping (177 cases and 219 controls) confirmed associations of HLA-A*0201 (P=2×10(-6)) and HLA-DQB1*0602 (P=5×10(-10)) and their interaction (P=.005). Additional, population-dependent effects were observed in HLA alleles with nominal significance. In an analysis of autoimmune-related genes, rs2476601 in the gene PTPN22 was associated (P=1.3×10(-4)). CONCLUSIONS Class I and II HLA genotypes affect susceptibility to AC-DILI, indicating the importance of the adaptive immune response in pathogenesis. The HLA genotypes identified will be useful in studies of the pathogenesis of AC-DILI but have limited utility as predictive or diagnostic biomarkers because of the low positive predictive values.

TM6SF2 rs58542926 influences hepatic fibrosis progression in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an increasingly common condition, strongly associated with the metabolic syndrome, that can lead to progressive hepatic fibrosis, cirrhosis and hepatic failure. Subtle inter-patient genetic variation and environmental factors combine to determine variation in disease progression. A common non-synonymous polymorphism in TM6SF2 (rs58542926 c.449 C>T, p.Glu167Lys) was recently associated with increased hepatic triglyceride content, but whether this variant promotes clinically relevant hepatic fibrosis is unknown. Here we confirm that TM6SF2 minor allele carriage is associated with NAFLD and is causally related to a previously reported chromosome 19 GWAS signal that was ascribed to the gene NCAN. Furthermore, using two histologically characterized cohorts encompassing steatosis, steatohepatitis, fibrosis and cirrhosis (combined n=1,074), we demonstrate a new association, independent of potential confounding factors (age, BMI, type 2 diabetes mellitus and PNPLA3 rs738409 genotype), with advanced hepatic fibrosis/cirrhosis. These findings establish new and important clinical relevance to TM6SF2 in NAFLD.

Hepatic adducts, circulating antibodies, and cytokine polymorphisms in patients with diclofenac hepatotoxicity.

Diclofenac is a nonsteroidal anti‐inflammatory drug that causes rare but serious hepatotoxicity, the mechanism of which is unclear. The purpose of the present study was to explore the potential role played by the immune processes. Antibodies to diclofenac metabolite‐modified liver protein adducts were detected in the sera of seven out of seven patients with diclofenac‐induced hepatotoxicity, 12 of 20 subjects on diclofenac without hepatotoxicity, and none of four healthy controls. The antibodies recognized adducts expressed in livers from rats treated with multiple doses of diclofenac, but not in those given single doses. In addition, several potential diclofenac adducts were identified in the liver of a patient with diclofenac‐induced hepatic failure, but not from a normal human donor liver, by immunoblotting with an adduct‐selective rabbit antiserum. To determine whether or not polymorphisms in genes encoding cytokine‐related proteins influence susceptibility to hepatotoxicity, genotyping for the polymorphisms ‐627 in the interleukin (IL)‐10 gene, ‐590 in the IL‐4 gene, and codon 551 in the IL‐4 receptor (IL‐4R) were performed on DNA from 24 patients on diclofenac with hepatotoxicity, 48 subjects on diclofenac without hepatotoxicity, and healthy controls. The frequencies of the variant alleles for IL‐10 and IL‐4 were higher in patients (OR [odds ratio]: 2.8 for IL‐10; 2.6 for IL‐4; 5.3 for IL‐10 + IL‐4) compared with healthy controls and subjects on diclofenac without hepatotoxicity (OR: 2.8 for IL‐10; 1.2 for IL‐4; 5.0 for IL‐10 + IL‐4). In conclusion, the observed polymorphisms, resulting in low IL‐10 and high IL‐4 gene transcription, could favor a T helper (Th)‐2 mediated antibody response to neoantigenic stimulation associated with disease susceptibility. HEPATOLOGY 2004;39:1430–1440.)

Incidence and prevalence of cirrhosis in the United Kingdom, 1992-2001 : A general population-based study

BACKGROUND/AIMS To determine the incidence and prevalence of cirrhosis in the United Kingdom. METHODS We identified patients aged 25 or over with cirrhosis, oesophageal varices or portal hypertension from the UK General Practice Research Database between 1992 and 2001. We measured incidence rates by sex, year and aetiology, incidence rate ratios and estimated prevalence figures. RESULTS Three thousand three hundred and sixty cases of cirrhosis were identified. Crude incidence was 14.55 per 100,000 person years increasing from 12.05 to 16.99 per 100,000 person years from 1992 to 2001. Incidence was over 50% higher in men compared with women (adjusted incidence rate ratio 1.52 (95%CI [1.42-1.63])). A statistically significant increase in incidence of both alcoholic cirrhosis and non-alcohol-related cirrhosis was seen in men and women. Prevalence of cirrhosis was an estimated 76.3 per 100,000 population aged over 25 in mid-2001. CONCLUSIONS There was a 45% increase in the incidence of cirrhosis during the decade 1992-2001 in the UK and a 68% increase in prevalence. Cirrhosis occurred more commonly and at younger ages in men than women. Cirrhosis represents a growing burden of morbidity and mortality in the UK, with an estimated 30,000 people living with cirrhosis and at least 7000 new cases being diagnosed each year.

Monitoring methotrexate-induced hepatic fibrosis in patients with psoriasis: are serial liver biopsies justified?

Background : Reports that up to 26% of subjects with psoriasis develop cirrhosis have led to a recommendation of serial liver biopsies after each cumulative dose of 1500 mg of methotrexate.

Human leucocyte antigen class II genotype in susceptibility and resistance to co-amoxiclav-induced liver injury

BACKGROUND & AIMS Co-amoxiclav is one of the most common causes of drug-induced liver injury (DILI). Although there are previous reports of genetic associations between HLA class II and co-amoxiclav-related DILI, studies to date have been based on very small numbers from single centres only. In order to address this problem we have investigated the role of HLA class II DRB1 and DQB1 in 61 cases of co-amoxiclav DILI as part of a UK-wide multicentre study. METHODS HLA alleles and genotypes were compared with those of 40 individuals exposed to co-amoxiclav without toxicity (treated controls) and 191 population controls. RESULTS There were two significant findings from the study. First, HLA-DRB1*15 was increased in patients (53%) versus both treated (33%: OR=2.29: 95% CI: 1.00-5.26) and population controls (30%: OR=2.59:95% CI: 1.44-4.68: p=0.002). Second, DRB1*07 was found to be reduced in patients (9.8%) compared to both treated (35%: OR=0.18: 95% CI: 0.06-0.52: p=0.0011, pc=0.0154) and population controls (29%: OR=0.266: 95% CI: 0.11-0.65: p=0.0019, pc=0.0266). CONCLUSIONS These results confirm the previously reported significant genetic risk for HLA-DRB1*15 and also provide evidence of a protective effect of the HLA-DRB1*07 family of alleles. HLA alleles and haplotypes may be particularly important in susceptibility and resistance to co-amoxiclav-DILI, but it remains to be seen whether this effect is due to the identified alleles or others in close linkage disequilibrium elsewhere on the MHC.