Innovating Thiopurine Therapeutic Drug Monitoring: A Systematic Review and Meta-Analysis on DNA-Thioguanine Nucleotides (DNA-TG) as an Inclusive Biomarker in Thiopurine Therapy.

BACKGROUND AND OBJECTIVE: Thioguanine (TG), azathioprine (AZA), and mercaptopurine (MP) are thiopurine prodrugs commonly used to treat diseases, such as leukemia and inflammatory bowel disease (IBD). 6-thioguanine nucleotides (6-TGNs) have been commonly used for monitoring treatment. High levels of 6-TGNs in red blood cells (RBCs) have been associated with leukopenia, the cutoff levels that predict this side effect remain uncertain. Thiopurines are metabolized and incorporated into leukocyte DNA. Measuring levels of DNA-incorporated thioguanine (DNA-TG) may be a more suitable method for predicting clinical response and toxicities such as leukopenia. Unfortunately, most methodologies to assay 6-TGNs are unable to identify the impact of NUDT15 variants, effecting mostly ethnic populations (e.g., Chinese, Indian, Malay, Japanese, and Hispanics). DNA-TG tackles this problem by directly measuring thioguanine in the DNA, which can be influenced by both TPMT and NUDT15 variants. While RBC 6-TGN concentrations have traditionally been used to optimize thiopurine therapy due to their ease and affordability of measurement, recent developments in liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques have made measuring DNA-TG concentrations in lymphocytes accurate, reproducible, and affordable. The objective of this systematic review was to assess the current evidence of DNA-TG levels as marker for thiopurine therapy, especially with regards to NUDT15 variants. METHODS: A systematic review and meta-analysis were performed on the current evidence for DNA-TG as a marker for monitoring thiopurine therapy, including methods for measurement and the illustrative relationship between DNA-TG and various gene variants (such as TPMT, NUDT15, ITPA, NT5C2, and MRP4). PubMed and Embase were systematically searched up to April 2024 for published studies, using the keyword "DNA-TG" with MeSH terms and synonyms. The electronic search strategy was augmented by a manual examination of references cited in articles, recent reviews, editorials, and meta-analyses. A meta-analysis was performed using R studio 4.1.3. to investigate the difference between the coefficients (Fisher's z-transformed correlation coefficient) of DNA-TG and 6-TGNs levels. A meta-analysis was performed using RevMan version 5.4 to investigate the difference in DNA-TG levels between patients with or without leukopenia using randomized effect size model. The risk of bias was assessed using the Newcastle-Ottowa quality assessment scale. RESULTS: In this systematic review, 21 studies were included that measured DNA-TG levels in white blood cells for either patients with ALL (n = 16) or IBD (n = 5). In our meta-analysis, the overall mean difference between patients with leukopenia (ALL + IBD) versus no leukopenia was 134.15 fmol TG/µg DNA [95% confidence interval (CI) (83.78-184.35), P < 0.00001; heterogeneity chi squared of 5.62, I2 of 47%]. There was a significant difference in DNA-TG levels for patients with IBD with and without leukopenia [161.76 fmol TG/µg DNA; 95% CI (126.23-197.29), P < 0.00001; heterogeneity chi squared of 0.20, I2 of 0%]. No significant difference was found in DNA-TG level between patients with ALL with or without leukopenia (57.71 fmol TG/µg DNA [95% CI (- 22.93 to 138.35), P < 0.80]). DNA-TG monitoring was found to be a promising method for predicting relapse rates in patients with ALL, and DNA-TG levels are likely a better predictor for leukopenia in patients with IBD than RBC 6-TGNs levels. DNA-TG levels have been shown to correlate with various gene variants (TPMT, NUDT15, ITPA, and MRP4) in various studies, points to its potential as a more informative marker for guiding thiopurine therapy across diverse genetic backgrounds. CONCLUSIONS: This systematic review strongly supports the further investigation of DNA-TG as a marker for monitoring thiopurine therapy. Its correlation with treatment outcomes, such as relapse-free survival in ALL and the risk of leukopenia in IBD, underscores its role in enhancing personalized treatment approaches. DNA-TG effectively identifies NUDT15 variants and predicts late leukopenia in patients with IBD, regardless of their NUDT15 variant status. The recommended threshold for late leukopenia prediction in patients with IBD with DNA-TG is suggested to be between 320 and 340 fmol/µg DNA. More clinical research on DNA-TG implementation is mandatory to improve patient care and to improve inclusivity in thiopurine treatment.

Unrealized potential of drug repositioning in europe during COVID-19 and beyond: a physcian's perspective.

Drug repositioning is the scientific strategy of investigating existing drugs for additional clinical indications. The advantages of drug repositioning are that it benefits patients and that it adds new indications to existing drugs for lower costs compared to de novo drug development. Clinical research groups recognizing efficacy of these "old" drugs for a new indications often face an uphill struggle due to a lack of funding and support because of poor structural and regulatory support for clinical drug development. The current framework for drug repositioning allows "venture capital" companies to abuse loopholes in the legislation to gain long-term market authorization among with excessive high pricing. A new regulatory framework is needed to prevent abuse of the legislation and promote clinical investigator-driven drug repositioning. The COVID-19 pandemic has boosted funding and regulatory support for drug repositioning. The lessons learned from the COVID-19 pandemic should be implemented in a new clear blueprint for drug repositioning. This blueprint should guide clinicians through legislation for drug repositioning in the EU. This review summarizes the routes for registration and discusses the current state of drug repositioning in Europe.

Multitarget Stool DNA Test Performance in an Average-Risk Colorectal Cancer Screening Population.

INTRODUCTION: We set out to evaluate the performance of a multitarget stool DNA (MT-sDNA) in an average-risk colonoscopy-controlled colorectal cancer (CRC) screening population. MT-sDNA stool test results were evaluated against fecal immunochemical test (FIT) results for the detection of different lesions, including molecularly defined high-risk adenomas and several other tumor characteristics. METHODS: Whole stool samples (n = 1,047) were prospectively collected and subjected to an MT-sDNA test, which tests for KRAS mutations, NDRG4 and BMP3 promoter methylation, and hemoglobin. Results for detecting CRC (n = 7), advanced precancerous lesions (advanced adenoma [AA] and advanced serrated polyps; n = 119), and non-AAs (n = 191) were compared with those of FIT alone (thresholds of 50, 75, and 100 hemoglobin/mL). AAs with high risk of progression were defined by the presence of specific DNA copy number events as measured by low-pass whole genome sequencing. RESULTS: The MT-sDNA test was more sensitive than FIT alone in detecting advanced precancerous lesions (46% (55/119) vs 27% (32/119), respectively, P < 0.001). Specificities among individuals with nonadvanced or negative findings (controls) were 89% (791/888) and 93% (828/888) for MT-sDNA and FIT testing, respectively. A positive MT-sDNA test was associated with multiple lesions (P = 0.005), larger lesions (P = 0.03), and lesions with tubulovillous architecture (P = 0.04). The sensitivity of the MT-sDNA test or FIT in detecting individuals with high-risk AAs (n = 19) from individuals with low-risk AAs (n = 52) was not significantly different. DISCUSSION: In an average-risk screening population, the MT-sDNA test has an increased sensitivity for detecting advanced precancerous lesions compared with FIT alone. AAs with a high risk of progression were not detected with significantly higher sensitivity by MT-sDNA or FIT.

Update of treatment algorithms for Clostridium difficile infection.

BACKGROUND: Clostridium difficile is the leading cause of antibiotic-associated diarrhoea, both in healthcare facilities and in the community. The recurrence rate of C. difficile infection (CDI) remains high, up to 20%. Since the publication of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidance document on CDI treatment in 2014, new therapeutic approaches have been developed and tested to achieve higher sustained clinical cure in CDI. AIM: To review novel treatments and approaches for CDI, except probiotics and vaccines. We focused on new antibiotics, antibiotic inactivators, monoclonal antibodies and gut microbiota modulating therapies. SOURCES: A literature review was performed for clinical trials published in PubMed, Embase or Cochrane Library between January 2013 and November 2017. CONTENT: We analysed 28 clinical trials and identified 14 novel agents. Completed phase 2 studies were found for cadazolid, LFF571, ridinilazole and nontoxigenic C. difficile strains. Four phase 3 active comparator studies comparing vancomycin with bezlotoxumab, surotomycin (n = 2) and rifaximin have been published. Seven clinical trials for treatment of multiple recurrent CDI with faecal microbiota transplantation were analysed, describing faecal microbiota transplantation by upper or lower gastrointestinal route (n = 5) or by capsules (n = 2). IMPLICATIONS: Metronidazole is mentioned in the ESCMID guideline as first-line therapy, but we propose that oral vancomycin will become the first choice when antibiotic treatment for CDI is necessary. Fidaxomicin is a good alternative, especially in patients at risk of relapse. Vancomycin combined with faecal microbiota transplantation remains the primary therapy for multiple recurrent CDI. We anticipate that new medication that protects the gut microbiota will be further developed and tested to prevent CDI during antibiotic therapy.

[Continued development of drugs: the path of thioguanine]. / Van doorontwikkeling van een geneesmiddel tot registratie-uitbreiding.

Continued development of existing drugs ('drug rediscovery') may offer new therapeutic options and be cost-effective. Rediscovered drugs are commonly prescribed off-label, although licensing can be important to allow safe and controlled prescription of the drugs to patients. Licensing of a new indication for a generic drug, however, is a complicated process since there is no blueprint for this and there is little interest from the pharmaceutical industry due to an unattractive cost-recovery model. In this article, we illustrate the successful license-extension for thioguanine - initially developed in 1950 for leukaemia - as a new treatment for patients with inflammatory bowel disease.

Host factors are more important in predicting recurrent Clostridium difficile infection than ribotype and use of antibiotics.

OBJECTIVE: A frequent complication of Clostridium difficile infection (CDI) is recurrent disease. The aim of this study was to determine whether early recurrence risk was higher after infection with ribotype 027 (outbreak strain) compared with infection with endemic strain types of C. difficile. METHODS: Consecutive patients diagnosed with CDI between May 2013 and March 2014 were included (outbreak strain, and non-outbreak strains). Patients who developed recurrent CDI within 30 days after completion of CDI treatment, were compared with patients without a recurrence. Medical charts were reviewed for demographic and clinical characteristics. General practitioners were contacted to complete data about the occurrence of recurrent CDI, and the use of medication after hospital discharge. RESULTS: In total, 135 patients were at risk for the development of recurrent CDI; 74 patients were infected by ribotype 027, and 61 patients by other ribotypes. Thirty-nine patients (29%) developed recurrent CDI within 30 days after completion of CDI treatment. In multivariable analysis, age ≥70 years (HR 3.05, 95% CI 1.54-6.03), and a duration of CDI treatment ≥11 days (HR 1.92, 95% CI 1.00-3.69) were clearly associated with recurrence; infection with ribotype 027 showed a HR of 1.72 (95% CI 0.88-3.33). CONCLUSION: During this outbreak of C. difficile in a tertiary care centre, age and a prolonged duration of CDI therapy (which is most likely a marker of underlying disease severity) were the main risk factors for recurrent CDI. This points to host factors as more important predictors for recurrent CDI than strain type or antibiotic use.

[Faecal microbiota transplantation: indications in perspective]. / Fecestransplantatie: wanneer wel en wanneer niet?

- As yet, with cure rates around 85%, recurrent Clostridium difficile infection is the only definite indication for faecal microbiota transplantation.- Faecal microbiota transplantation induces clinical remission and endoscopic improvements in 24-30% of patients with ulcerative colitis, compared to 5% (water) to 20% (autologous faeces) in placebo-treated patients. Current research focuses on the identification of 'super donors', and subgroups of patients in which faecal microbiota transplantation is effective.- In patients with metabolic syndrome, faecal microbiota transplantation may increase insulin sensitivity. Weight, body mass index, and energy metabolism are not affected by faecal microbiota transplantation in humans.- In addition to the aforementioned indications, faecal microbiota transplantation is an emerging treatment modality for patients with Crohn's disease, irritable bowel syndrome, graft-versus-host-disease, and carriage of multidrug-resistant micro-organisms. Randomized controlled trials, comparing faecal microbiota transplantation with placebo treatment, are required to determine the effectiveness of faecal microbiota transplantation in these patient groups.

Oesophageal squamous cell cancer in a South African tertiary hospital: a risk factor and presentation analysis.

BACKGROUND: Squamous carcinoma of the oesophagus (SCO) is the most common form of oesophageal cancer in South Africa (SA). Risk factors include male gender, smoking, alcohol consumption and low socio-economic status (SES). This study assessed the risk factors for SCO in KwaZulu-Natal. METHOD: Information on patients managed at Inkosi Albert Luthuli Central Hospital (IALCH), Durban, South Africa, between 1 October 2013 and 31 December 2014 was retrieved from a prospective database of Oesophageal Cancer (OC). Data collected included demographics, risk factors, symptoms and clinical findings. RESULTS: One hundred and fifty-nine patients (159) with SCO were identified. The site of tumour location was in the middle 96 (60.4%), distal 42(26.4%) and proximal 17(10.6%) oesophagus. The male to female ratio was 1:1 with an age range of 22-93 years (mean 60.6; SD±12.1). Females were significantly older than males (p = 0.018). Eighty-eight per cent were Black African. Dysphagia was reported in 158 (99.4%) of patients and loss of weight in 149(95.5%). Thirty-six patients were HIV positive (age 52.8; SD±9.7) and significantly younger than those without HIV infection (age 61.2; SD±11.5). Most patients had low SES and poor dental health. Male patients were significantly more likely to use tobacco (p < 0.001; Odds Ratio (OR) 7.8) and consume alcohol (p < 0.001; OR 7.7) than females who were 2.5 times more likely to report a family history of cancer (p = 0.017; OR 2.6). CONCLUSION: An equal gender distribution was observed. Male patients with SCO reported the expected risk factors; however these were not observed amongst women. SES may contribute to the development of SCO. Poor dental health may be a surrogate marker for low SES and a possible risk factor for SCO. HIV positive individuals present a decade younger when compared with HIV negative patients.

How to: Establish and run a stool bank.

BACKGROUND: Since 2013, several stool banks have been developed following publications reporting on clinical success of 'faecal microbiota transplantation' (FMT) for recurrent Clostridium difficile infections (CDI). However, protocols for donor screening, faecal suspension preparation, and transfer of the faecal suspension differ between countries and institutions. Moreover, no European consensus exists regarding the legislative aspects of the faecal suspension product. Internationally standardized recommendations about the above mentioned aspects have not yet been established. OBJECTIVE: In 2015, the Netherlands Donor Feces Bank (NDFB) was founded with the primary aim of providing a standardized product for the treatment of patients with recurrent CDI in the Netherlands. Standard operation procedures for donor recruitment, donor selection, donor screening, and production, storage, and distribution of frozen faecal suspensions for FMT were formulated. RESULTS AND DISCUSSION: Our experience summarized in this review addresses current donor recruitment and screening, preparation of the faecal suspension, transfer of the faecal microbiota suspension, and the experiences and follow-up of the patients treated with donor faeces from the NDFB.

Cost analysis of an outbreak of Clostridium difficile infection ribotype 027 in a Dutch tertiary care centre.

BACKGROUND: The economic impact of Clostridium difficile infection (CDI) on the healthcare system is significant. From May 2013 to May 2014, an outbreak of C. difficile ribotype 027 occurred in a Dutch tertiary care hospital, involving 72 patients. The primary aim of this study was to provide insight into the financial burden that this CDI outbreak brought upon this hospital. METHODS: A retrospective analysis was performed to estimate the costs of a one-year-long C. difficile ribotype 027 outbreak. Medical charts were reviewed for patient data. In addition, all costs associated with the outbreak control measures were collected. FINDINGS: The attributable costs of the whole outbreak were estimated to be €1,222,376. The main contributing factor was missed revenue due to increased length of stay of CDI patients and closure of beds to enable contact isolation of CDI patients (36%). A second important cost component was extra surveillance and activities of the Department of Medical Microbiology and Infection Control (25%). CONCLUSION: To the authors' knowledge, this is the first study to provide insight into the attributable costs of CDI in an outbreak setting, and to delineate the major cost items. It is clear that the economic consequences of CDI are significant. The high costs associated with a CDI outbreak should help to justify the use of additional resources for CDI prevention and control.

Gastrointestinal diseases and their oro-dental manifestations: Part 3: Coeliac disease.

Coeliac disease is a chronic autoimmune-mediated enteropathy, caused by exposure to dietary gluten in genetically predisposed individuals that affects approximately 0.5-1% of the western population. Despite increased awareness of the disease, the majority of patients still remain undiagnosed. Disease frequently manifests in early childhood, but a significant proportion of patients are nowadays diagnosed above the age of 50. Timely diagnosis is important in order to start a gluten-free diet and prevent complications. Symptoms of coeliac disease vary widely and are certainly not restricted to the intestine. They may include, among others, dental and oral manifestations. Most of them are nonspecific but symmetric enamel defects are very specific to coeliac disease. It is important to recognise this relationship since it may help to identify unrecognised patients.

Outcome of Referrals for Non-Responsive Celiac Disease in a Tertiary Center: Low Incidence of Refractory Celiac Disease in the Netherlands.

OBJECTIVES: Refractory celiac disease (RCD) is a severe cause of non-responsive celiac disease (CD) due to its association with the enteropathy associated T-cell lymphoma (EATL). Conflicting data exist on the prevalence and the clinical manifestations of RCD type I (RCD I) and type II (RCD II). The aim of the current study was to provide insight in the incidence of RCD and in the distinction with other causes of non-responsive CD. METHODS: A total of 106 CD patients were referred to our tertiary referral center between January 2006 and December 2011 for evaluation of non-responsive CD. In addition, a questionnaire was sent to all 82 gastroenterology departments in the Netherlands to reveal whether a patient with RCD was currently being evaluated or had been treated between 2006 and 2012. RESULTS: During a 6 year period, a total of 31 patients were diagnosed with RCD (19 RCD I and 12 RCD II). The nationwide survey revealed 5 additional patients with RCD I and one patient with RCD II. This leads to an annual incidence of RCD of 0.83/10.000 CD patients. The remaining patients were diagnosed with involuntary gluten ingestion (21.7%), delayed mucosal recovery (11.3%), enteropathy associated T-cell lymphoma (7.5%) and autoimmune enteropathy (1.8%). CONCLUSIONS: This nationwide study reveals a low incidence of RCD in the Netherlands. Nevertheless, RCD is a clinically relevant disease entity in CD patients non-responsive to the gluten-free diet.

Is Clinical Research in Oesophageal Cancer in South Africa in Crisis? A Systematic Review.

Oesophageal cancer (OC) is responsible for the second highest number of cancer-related deaths in South Africa (SA). Squamous cell carcinoma is the most prevalent type with an incidence of 46.7/100,000 and 19.2/100,000 for males and females. This is a systematic review of the clinical diagnosis and management of OC within the South African context. This protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (registration number CRD42016034053) with adherence to PRISMA guidelines. An online search was performed using MEDLINE, EBSCOHost and PubMed. Eligibility criteria for articles included published, original peer-reviewed research addressing clinical management of oesophageal cancer in South Africa. Review articles, case reports, scientific letters and studies published in languages other than English or Afrikaans were excluded. The research terms were 'etiology', 'human', 'esophageal cancer', 'esophageal carcinoma', 'oesophageal cancer', and 'oesophageal carcinoma', 'squamous cell carcinoma', 'Africa' and 'South Africa'. A total of 336 articles were identified. Of these, 146 were immediately excluded and a further 159 were excluded after review. A total of 31 appropriate articles, i.e. 9.2% of searched articles, were included. Thirteen articles addressed chemotherapy and/or radiotherapy, 9 oesophageal luminal therapy, 7 oesophageal surgery and 2 screening. OC research of in SA over the last two decades has mainly been in the form of reviews and opinion papers. Clinical research, auditing and prospectively analysing OC management and outcomes in SA hospitals are sorely needed and should be promoted by both healthcare workers and policy makers alike.

Creation of a model to predict survival in patients with refractory coeliac disease using a multinational registry.

BACKGROUND: Refractory coeliac disease is a severe complication of coeliac disease with heterogeneous outcome. AIM: To create a prognostic model to estimate survival of patients with refractory coeliac disease. METHODS: We evaluated predictors of 5-year mortality using Cox proportional hazards regression on subjects from a multinational registry. Bootstrap resampling was used to internally validate the individual factors and overall model performance. The mean of the estimated regression coefficients from 400 bootstrap models was used to derive a risk score for 5-year mortality. RESULTS: The multinational cohort was composed of 232 patients diagnosed with refractory coeliac disease across seven centres (range of 11-63 cases per centre). The median age was 53 years and 150 (64%) were women. A total of 51 subjects died during a 5-year follow-up (cumulative 5-year all-cause mortality = 30%). From a multiple variable Cox proportional hazards model, the following variables were significantly associated with 5-year mortality: age at refractory coeliac disease diagnosis (per 20 year increase, hazard ratio = 2.21; 95% confidence interval, CI: 1.38-3.55), abnormal intraepithelial lymphocytes (hazard ratio = 2.85; 95% CI: 1.22-6.62), and albumin (per 0.5 unit increase, hazard ratio = 0.72; 95% CI: 0.61-0.85). A simple weighted three-factor risk score was created to estimate 5-year survival. CONCLUSIONS: Using data from a multinational registry and previously reported risk factors, we create a prognostic model to predict 5-year mortality among patients with refractory coeliac disease. This new model may help clinicians to guide treatment and follow-up.

Systematic review: periprocedural hydration in the prevention of post-ERCP pancreatitis.

BACKGROUND: With an overall incidence of 3.5%, pancreatitis is the most frequent complication of endoscopic retrograde cholangiopancreatography (ERCP). Periprocedural hydration may prevent post-ERCP pancreatitis by maintaining pancreatic microperfusion, thereby inhibiting the pancreatic inflammatory response. However, the evidence for periprocedural hydration as a preventive measure is unclear. AIM: To conduct a systematic review to assess the evidence regarding periprocedural hydration as a preventive measure for post-ERCP pancreatitis. METHODS: We searched PubMed and EMBASE databases and adhered to the PRISMA guidelines. We included studies addressing periprocedural hydration as a preventive measure to reduce frequency and severity of post-ERCP pancreatitis. Study quality was assessed by using the MINORS and Cochrane Collaboration's tool. RESULTS: Six studies with a total of 1102 patients were included. Two randomised controlled trials reported a decreased incidence of post-ERCP pancreatitis after hydration: 0% vs. 17% (P = 0.016) and 5.3% vs. 22.7% (P = 0.002). A third trial and two case-controls studies did not report significant differences. Two retrospective studies found that patients with mild post-ERCP pancreatitis had received significantly more fluids during (mean 940 mL vs. 810 mL; P = 0.031) or after ERCP (median 2834 mL vs. 2044 mL; P < 0.02) compared to patients with moderate/severe disease. Adverse events of periprocedural hydration were not reported in any of the included studies. The different methodologies of the included studies precluded a formal data synthesis. CONCLUSIONS: There is some evidence to suggest that hydration affords protection against post-ERCP pancreatitis, but study heterogeneity precludes firm conclusions. Adequately powered randomised trials are needed to evaluate the preventive effect of periprocedural hydration.

Novel variant of EATL evolving from mucosal γδ-T-cells in a patient with type I RCD.

OBJECTIVES: Enteropathy associated T-cell lymphoma (EATL) is a rare non-Hodgkin lymphoma that may complicate coeliac disease and typically occurs in patients with refractoriness to the gluten-free diet. The majority of these patients harbour a clonal expansion of intraepithelial lymphocytes (IELs) with an aberrant phenotype in the small intestine which are thus considered as the 'precursor' lymphoma cells. We describe a 51-year-old female patient with refractory coeliac disease (RCD) who developed an EATL with manifestations in the proximal small intestine and in a mesenteric lymph node that did not evolve from regular type 'aberrant' αß-T-cells but rather from a clonal expansion of γδ-T-cells. METHODS: Duodenal biopsies and lymphoma tissue from a patient with refractory coeliac disease whom developed an EATL were extensively studied by immunophenotypical, T-cell receptor immunogenetic and chromosomal analysis. RESULTS: Flow cytometric analysis of duodenal IELs revealed an unusual large clonal expansion of CD30 negative γδ-T-cells in a patient with RCD. When the patient clinically deteriorated 18 months later, a substantial part (30%) of this cell population did express CD30. In addition, identical immunogenetic aberrancies had developed in a prehepatic lymph node. CONCLUSIONS: We here report on a case of extraintestinal EATL that originated from a clonal γδ-IEL population rather than from aberrant IEL. This EATL displayed a distinctive pattern of immunophenotypical, T-cell receptor immunogenetic and chromosomal aberrancies as compared to classical EATL, defining this lymphoma as a novel variant of EATL.

HLA-DRB1*03:01 and HLA-DRB1*04:01 modify the presentation and outcome in autoimmune hepatitis type-1.

The classical human leukocyte antigen (HLA)-DRB1*03:01 and HLA-DRB1*04:01 alleles are established autoimmune hepatitis (AIH) risk alleles. To study the immune-modifying effect of these alleles, we imputed the genotypes from genome-wide association data in 649 Dutch AIH type-1 patients. We therefore compared the international AIH group (IAIHG) diagnostic scores as well as the underlying clinical characteristics between patients positive and negative for these HLA alleles. Seventy-five percent of the AIH patients were HLA-DRB1*03:01/HLA-DRB1*04:01 positive. HLA-DRB1*03:01/HLA-DRB1*04:01-positive patients had a higher median IAIHG score than HLA-DRB1*03:01/HLA-DRB1*04:01-negative patients (P<0.001). We did not observe associations between HLA alleles and alanine transaminase levels (HLA-DRB1*03:01: P=0.2; HLA-DRB1*04:01; P=0.5); however, HLA-DRB1*03:01 was independently associated with higher immunoglobulin G levels (P=0.04). The HLA-DRB1*04:01 allele was independently associated with presentation at older age (P=0.03) and a female predominance (P=0.04). HLA-DRB1*03:01-positive patients received immunosuppressive medication and liver transplantation. In conclusion, the HLA-DRB1*03:01 and HLA-DRB1*04:01 alleles are both independently associated with the aggregate diagnostic IAIHG score in type-1 AIH patients, but are not essential for AIH development. HLA-DRB1*03:01 is the strongest genetic modifier of disease severity in AIH.

Optimal strategies to identify aberrant intra-epithelial lymphocytes in refractory coeliac disease.

INTRODUCTION: Different strategies have been developed to identify those refractory celiac disease (RCD) patients who are at risk to develop an enteropathy associated T-cell lymphoma (EATL). Flow cytometric analysis of intra-epithelial lymphocytes (IEL) with an aberrant phenotype is considered the golden standard but is not widely available. Immunohistochemistry (IHC) and T-cell receptor (TCR) rearrangement studies are commonly available but may lack sensitivity and specificity. Here, we compared the three different methods in the workup of patients suspected for RCD. METHODS: Duodenal biopsies from control patient (n = 5), RCD patients with moderately increased aberrant IEL populations (20-50 %: n = 14), and RCD patients with high numbers of aberrant IEL (>50 %: n = 5) as determined by flow cytometry were analysed by IHC and TCR-γ chain rearrangement analysis. Three pathologists scored the slides independently. RESULTS: Sensitivity of IHC and TCR-γ rearrangement analysis in RCD patients with high numbers of aberrant IELs was 100 and 71 %, respectively. RCD patients with aberrant cells between 25 and 50 % however, were missed by IHC and TCR in 50 and 57 % of cases, respectively. In addition, inter-rater reliability analysis of the IHC scoring revealed coder-pair Kappa coefficients between 0.28 and 0.85. CONCLUSION: Immunohistochemistry and to a lesser extent TCR-γ clonality analysis are sensitive in identifying patients with high numbers of aberrant IEL populations, yet miss half of RCD patients with moderately increased numbers. In addition, IHC has a high inter-observer variability. Therefore, patients suspected for RCD should undergo flow cytometric analysis of the duodenum.