Wieke H. Verbeek

Newly identified genetic risk variants for celiac disease related to the immune response

Our genome-wide association study of celiac disease previously identified risk variants in the IL2–IL21 region. To identify additional risk variants, we genotyped 1,020 of the most strongly associated non-HLA markers in an additional 1,643 cases and 3,406 controls. Through joint analysis including the genome-wide association study data (767 cases, 1,422 controls), we identified seven previously unknown risk regions (P < 5 × 10−7). Six regions harbor genes controlling immune responses, including CCR3, IL12A, IL18RAP, RGS1, SH2B3 (nsSNP rs3184504) and TAGAP. Whole-blood IL18RAP mRNA expression correlated with IL18RAP genotype. Type 1 diabetes and celiac disease share HLA-DQ, IL2–IL21, CCR3 and SH2B3 risk regions. Thus, this extensive genome-wide association follow-up study has identified additional celiac disease risk variants in relevant biological pathways.

Coeliac disease-associated risk variants in TNFAIP3 and REL implicate altered NF-κB signalling

Objective: Our previous coeliac disease genome-wide association study (GWAS) implicated risk variants in the human leucocyte antigen (HLA) region and eight novel risk regions. To identify more coeliac disease loci, we selected 458 single nucleotide polymorphisms (SNPs) that showed more modest association in the GWAS for genotyping and analysis in four independent cohorts. Design: 458 SNPs were assayed in 1682 cases and 3258 controls from three populations (UK, Irish and Dutch). We combined the results with the original GWAS cohort (767 UK cases and 1422 controls); six SNPs showed association with p<1×10−04 and were then genotyped in an independent Italian coeliac cohort (538 cases and 593 controls). Results: We identified two novel coeliac disease risk regions: 6q23.3 (OLIG3-TNFAIP3) and 2p16.1 (REL), both of which reached genome-wide significance in the combined analysis of all 2987 cases and 5273 controls (rs2327832 p = 1.3×10−08, and rs842647 p = 5.2×10−07). We investigated the expression of these genes in the RNA isolated from biopsies and from whole blood RNA. We did not observe any changes in gene expression, nor in the correlation of genotype with gene expression. Conclusions: Both TNFAIP3 (A20, at the protein level) and REL are key mediators in the nuclear factor kappa B (NF-κB) inflammatory signalling pathway. For the first time, a role for primary heritable variation in this important biological pathway predisposing to coeliac disease has been identified. Currently, the HLA risk factors and the 10 established non-HLA risk factors explain ∼40% of the heritability of coeliac disease.

Common and different genetic background for rheumatoid arthritis and coeliac disease

Recent genome-wide association studies (GWAS) have revealed genetic risk factors in autoimmune and inflammatory disorders. Several of the associated genes and underlying pathways are shared by various autoimmune diseases. Rheumatoid arthritis (RA) and coeliac disease (CD) are two autoimmune disorders which have commonalities in their pathogenesis. We aimed to replicate known RA loci in a Dutch RA population, and to investigate whether the effect of known RA and CD risk factors generalize across the two diseases. We selected all loci associated to either RA or CD in a GWAS and confirmed in an independent cohort, with a combined P-value cut-off P < 5 x 10(-6). We genotyped 11 RA and 11 CD loci in 1368 RA patients, 795 CD patients and 1683 Dutch controls. We combined our results in a meta-analysis with UK GWAS on RA (1860 cases; 2938 controls) and CD (767 cases; 1422 controls). In the Dutch RA cohort, the PTPN22 and IL2/IL21 variants showed convincing association (P = 3.4 x 10(-12) and P = 2.8 x 10(-4), respectively). Association of RA with the known CD risk variant in the SH2B3 was also observed, predominantly in the subgroup of rheumatoid factor-positive RA patients (P = 0.0055). In a meta-analysis of Dutch and UK data sets, shared association with six loci (TNFAIP3, IL2/IL21, SH2B3, LPP, MMEL1/TNFRSF14 and PFKFB3/PRKCQ) was observed in both RA and CD cohorts. We confirmed two known loci and identified four novel ones for shared CD-RA genetic risk. Most of the shared loci further emphasize a role for adaptive and innate immunity in these diseases.

Enteropathy associated T-cell lymphoma and its precursor lesions

Enteropathy Associated T-cell Lymphoma (EATL) is an intestinal tumour of intra-epithelial lymphocytes. Based on morphology, immunohistochemistry and genetic profile EATL can be divided into two groups. EATL type I is a large cell lymphoma which is highly associated with Coeliac Disease (CD) and mostly presents with malabsorption, weight loss and CD-related symptoms. EATL type II consists of small to medium-sized cells and presents often with obstruction or perforation of the small bowel. This type of EATL has no known association with CD. When EATL has been diagnosed a thorough diagnostic work-up is needed. This work-up preferably includes video capsule enteroscopy (VCE), double-balloon enteroscopy (DBE), computed tomography (CT) combined with 18F-fluorodeoxyglucose positron emission tomography scan (18F-FDG-PET scan) if possible and magnetic resonance enteroclysis (MRE). Nowadays, most EATL patients are treated with chemotherapy mostly preceded by resection of the tumour and followed by stem cell transplantation. Despite these therapies outcome of EATL remains very poor with a 5-year survival of 8-20%. In order to improve survival prospective multicentre trials, studying new therapies are needed. The combination of chemotherapy, monoclonal antibodies and/or apoptosis inducing small molecules might be a potential treatment for EATL in the (nearby) future.

Incidence of enteropathy -associated T-cell lymphoma : A nation-wide study of a population-based registry in The Netherlands

Objective. Enteropathy-associated T-cell lymphomas (EATLs) are T-cell non-Hodgkin lymphomas of the small bowel, which are specifically associated with coeliac disease (CD). To our knowledge no studies have previously reported on the overall incidence of EATLs in the general population. The aim of this study was to investigate the incidence of EATL and the demographic characteristics of patients with EATL in The Netherlands. Material and methods. A survey of the nation-wide network and registry of histo- and cytopathology reports in The Netherlands (PALGA) was performed. We included all T-cell lymphomas detected between January 2000 and December 2006 that initially presented in the small bowel. Crude and world standardized incidence rates were computed as well as gender- and age-specific incidence rates. Finally, the distribution of characteristics such as the localization, the Marsh classification and method of diagnosis are described. Results. Clinicopathological data were gathered for 116 cases of EATL. The mean age at primary presentation of EATL was 64 years. The crude incidence in the total Dutch population was 0.10/100,000 with an incidence of 2.08/100,000 in the over 50-year-olds. Age-specific incidences were 1.44/100,000 in the 50–59 years age group, 2.92/100,000 in the 60–69 years age group, and 2.53/100,000 in the 70–79 years age group. There was a significant predominance of males (64%, p=0.004, CI 54–72); above the age of 50 the gender-specific incidence was 2.95/100,000 in males versus 1.09/100,000 in females. Most EATLs were localized in the proximal small intestine and the diagnosis was made by surgical resection in the majority of cases. Conclusions. EATL is a rare disease with an incidence of 0.10 per 100,000 inhabitants per year, occurring in older age, with a peak incidence in the 7th decade. The tumour is mainly localized in the proximal small intestine. Although uncomplicated CD is twice as frequent in female patients, EATL is more prevalent in males.

Auto-SCT in refractory celiac disease type II patients unresponsive to cladribine therapy

Autologous hematopoietic SCT (auto-SCT) has been effective therapy for refractory disease, in both malignancies and severe autoimmune diseases. It seems feasible and safe for refractory celiac disease (RCD) type II, although long-term results have not been evaluated yet. With current therapies, progression into enteropathy-associated T-cell lymphoma (EATL) occurs in 60–80% patients, with a high mortality rate. Therefore, it is important to evaluate new treatment strategies. Between March 2004 and February 2010, 18 RCD II patients were evaluated for auto-SCT preceded by conditioning with fludarabine and melphalan, as a consequence of unresponsiveness to cladribine therapy. Adverse events, survival rate, EATL development and change in clinical, histological and immunological course were monitored. Thirteen patients were transplanted successfully and followed up for >2 years, 4-year survival rate was 66%. Only one patient died because of transplant-related complications. The majority of patients showed an impressive clinical improvement and five a complete histological remission. In five patients, auto-SCT could not be performed; they all died with a median survival of 5.5 months. EATL was observed in one transplanted patient, only after 4 years of follow-up. Auto-SCT after conditioning with high-dose chemotherapy in RCD II patients unresponsive to cladribine therapy is feasible and seems promising.

Update on the management of refractory coeliac disease.

True Refractory Coeliac Disease (RCD) is being currently defined as persisting or recurring villous atrophy with crypt hyperplasia and increased intraepithelial lymphocytes in spite of a strict gluten free diet for more than 12 months or when severe persisting symptoms necessitate intervention independent of the duration of the dietary therapy. Currently two categories of RCD are being recognized: type I without aberrant T-cells and type II with aberrant T-cells detected by immunophenotyping by flowcytometric analysis or immunohistology of the intestinal mucosa. Establishing the diagnosis of RCD requires exclusion of other causes of villous atrophy and malignancies that may complicate coeliac disease. In contrast to patients with a high percentage of aberrant T cells, patients with RCD type I seem to profit from an immunosuppressive treatment. In cases of RCD II with persistent clinical symptoms and/or high percentage of aberrant T cells in intestinal biopsies in spite of a corticosteroid treatment, more aggressive therapeutic schemes should be considered. However, no therapy seems to be curative in RCD II. Cladribine (2-CDA) seems to have some role in the management of these patients. More recently, high dose chemotherapy followed by autologous stem cell transplantation has been used in patients resulting in a dramatic improvement in the clinical, laboratory, histopathological and immunological parameters. This review provides an overview of the currently available diagnostic and therapeutic methods in a complicated form of coeliac disease.

Defective synthesis or association of T-cell receptor chains underlies loss of surface T-cell receptor–CD3 expression in enteropathy-associated T-cell lymphoma

Enteropathy-associated T-cell lymphoma, an often fatal complication of celiac disease, can result from expansion of aberrant intraepithelial lymphocytes in refractory celiac disease type II (RCD II). Aberrant intraepithelial lymphocytes and lymphoma cells are intracellularly CD3epsilon(+) but lack expression of the T-cell receptor (TCR)-CD3 complex on the cell surface. It is unknown what causes the loss of TCR-CD3 expression. We report the isolation of a cell line from an RCD II patient with the characteristic phenotype of enteropathy-associated T-cell lymphoma. We demonstrate that in this cell line the TCR-alpha and -beta chains as well as the CD3gamma, CD3delta, CD3epsilon, and zeta-chains are present intracellularly and that assembly of the CD3gammaepsilon, CD3deltaepsilon, and zetazeta-dimers is normal. However, dimerization of the TCR chains and proper assembly of the TCR-CD3 complex are defective. On introduction of exogenous TCR-beta chains, but not of TCR-alpha chains, assembly and functional cell surface expression of the TCR-CD3 complex were restored. Defective synthesis of both TCR chains was found to underlie loss of TCR expression in similar cell lines isolated from 2 additional patients. (Pre)malignant transformation in RCD II thus correlates with defective synthesis or defective association of the TCR chains, resulting in loss of surface TCR-CD3 expression.

Aberrant T-lymphocytes in refractory coeliac disease are not strictly confined to a small intestinal intraepithelial localization†

Refractory coeliac disease (RCD) is characterized by persisting mucosal pathology in spite of a strict gluten free diet (GFD). In RCD type II, phenotypically aberrant (CD7+CD3‐CD4/8‐cytoplasmicCD3+) T‐lymphocytes are present within the intraepitelial lymphocyte (IEL) population in the small intestine, and 50–60% of these patients develops an enteropathy associated T‐cell lymphoma (EATL).

Accurate classification of RCD requires flow cytometry

We read with interest the article of Liu et al in Gut , in which the authors emphasise the need for monitoring of clonality and intraepithelial lymphocyte (IEL) immunophenotype in the surveillance of refractory coeliac disease (RCD).1 The authors state there is no consensus on the cut-off of aberrant cells distinguishing between non-complicated coeliac disease (CD), RCD type I (RCDI) and RCD type II (RCDII). However, in 2000 it was shown that based on the number of aberrant T cells, CD can be distinguished from RCD by immunohistochemistry.2 Furthermore, using flow cytometry, Verbeek defined a clinically well-validated cut-off of 20% IELs as being diagnostic for RCDII.3 In their paper, the authors describe that a high percentage of patients (80%) progress from RCDI to RCDII. This is somewhat …