Marietta, Eric

Background and aims: Clinical experience suggests that patients with coeliac disease (CD) are more prone to develop herpes zoster (HZ), but robust studies are lacking. Methods: We identified 29,064 patients with CD 1969−2008 using biopsy report data from Sweden’s 28 pathology departments. CD was equalled to villous atrophy (Marsh histopathology grade III). Each patient was matched on age, sex, calendar year and county of residence to up to five reference individuals ( n=144,342) from the general population. We then used Cox regression to estimate hazard ratios (HRs) for future HZ (defined as having a hospital-based inpatient or outpatient record of this diagnosis in the Swedish Patient Register). Results: During follow-up, 154 (0.53%) individuals with CD and 499 (0.35%) reference individuals developed HZ. Among individuals aged ≥60 years, 1.06% of CD individuals and 0.85% of reference individuals had a lifetime record of HZ. Overall, CD was associated with a 1.62-fold increased risk of HZ (95% CI=1.35−1.95), and was seen also when we considered comorbidity with lymphoproliferative disease, systemic lupus erythematosus, type 1 diabetes, thyroid disease, rheumatoid disease and excluded individuals with a record of dermatitis herpetiformis. The increased risk remained significant after more than five years of follow-up (1.46; 1.16−1.84) Conclusions: CD is associated with HZ, the increased relative risk persists over time from celiac diagnosis but the absolute risk is small.

SummaryBackgroundTherapy for coeliac disease (CD) mainly relies on following a gluten‐free diet (GFD); however, a serum marker for gluten intake has yet to be established.AimTo evaluate the utility of alkylresorcinol concentrations for detecting gluten intake in studies of human and mouse.MethodsAlkylresorcinol concentrations were compared among treated patients with coeliac disease (n = 34), untreated coeliac disease patients (n = 36) and controls (n = 33). Furthermore, seven additional coeliac disease patients whose serum samples were available at diagnosis and after GFD were evaluated. In mice studies, alkylresorcinol concentrations were compared in the serum of five mice fed a regular chow and 10 mice fed lifelong with a gluten‐free chow. In addition, the effect of adding gluten on changes of alkylresorcinol concentrations was also evaluated.ResultsTotal alkylresorcinol concentrations were significantly lower in treated with coeliac disease [median (IQR), 3 (2–8) nmol/L], compared to untreated patients [median (IQR), 32 (11–74) nmol/L; P < 0.0001] or healthy controls [median (IQR), 54 (23–112) nmol/L; P < 0.0001]. Moreover, alkylresorcinol concentrations in coeliac disease patients significantly decreased after introduction of a GFD (median, 34 nmol/L at diagnosis vs. 5 nmol/L after GFD, P = 0.02). In the mice, median (IQR) total alkylresorcinol concentrations in serum samples of mice fed lifelong with a gluten‐free chow was 1.8 (1.6–2.3) nmol/L, which was further significantly increased to 16 (11–22) nmol/L after 8 days of feeding with the gluten‐free chow that had gluten added to it. (P = 0.008).ConclusionSerum alkylresorcinol concentrations could be a useful marker for dietary gluten in coeliac disease.

SummaryBackgroundAlthough eosinophilic oesophagitis (EoE) is putatively mediated by an abnormal response to food antigen, the oesophagus is considered relatively impermeable to large molecules.AimTo assess whether food antigens penetrate the oesophageal mucosa in patients with EoE.MethodsAnti‐gliadin staining was performed in three groups: active EoE, inactive EoE and EoE patients on a low or gluten free diet. To appraise the specificity of our results, we also performed gliadin staining on six patients without oesophageal disease who were consuming gluten. The groups with EoE on gluten also underwent endoscopic infusion with gluten containing soy sauce and repeat biopsies during the endoscopy. We measured eosinophil density, dilated intercellular spaces (on a 0–4+ scale) and gliadin in oesophageal mucosa by immunofluorescence.ResultsPatients with active EoE had significantly greater epithelial density of anti‐gliadin staining when compared to inactive EoE (P < 0.0065) and gluten‐free patients (P < 0.0008) at baseline and after soy infusion. Gliadin was not detected in non‐EoE control patients. The distribution of gliadin was both cytoplasmic and nuclear. There was good correlation of dilated intercellular spaces grade and total gliadin staining intensity (r = 0.577, P = 0.0077). Acute oesophageal perfusion of a commercial gliadin‐rich soy sauce did not lead to an increase in gliadin staining in active or inactive EoE.ConclusionThese findings suggest, although do not prove, that antigen penetration in active eosinophilic oesophagitis might be facilitated by impairment of epithelial integrity.

ObjectiveThe gut microbiome regulates host immune homeostasis. Rheumatoid arthritis (RA) is associated with intestinal dysbiosis. This study was undertaken to test the ability of a human gut‐derived commensal to modulate immune response and treat arthritis in a humanized mouse model.MethodsWe isolated a commensal bacterium, Prevotella histicola, that is native to the human gut and has systemic immune effects when administered enterally. Arthritis‐susceptible HLA–DQ8 mice were immunized with type II collagen and treated with P histicola. Disease incidence, onset, and severity were monitored. Changes in gut epithelial proteins and immune response as well as systemic cellular and humoral immune responses were studied in treated mice.ResultsWhen treated with P histicola in prophylactic or therapeutic protocols, DQ8 mice exhibited significantly decreased incidence and severity of arthritis compared to controls. The microbial mucosal modulation of arthritis was dependent on regulation by CD103+ dendritic cells and myeloid suppressors (CD11b+Gr‐1+ cells) and by generation of Treg cells (CD4+CD25+FoxP3+) in the gut, resulting in suppression of antigen‐specific Th17 responses and increased transcription of interleukin‐10. Treatment with P histicola led to reduced intestinal permeability by increasing expression of enzymes that produce antimicrobial peptides as well as tight junction proteins (zonula occludens 1 and occludin). However, the innate immune response via Toll‐like receptor 4 (TLR‐4) and TLR‐9 was not affected in treated mice.ConclusionOur results demonstrate that enteral exposure to P histicola suppresses arthritis via mucosal regulation. P histicola is a unique commensal that can be explored as a novel therapy for RA and may have few or no side effects.

Celiac disease (CD) is an inflammatory disorder triggered by ingested gluten, causing immune-mediated damage to the small-intestinal mucosa. Gluten proteins are strikingly similar in amino acid composition and sequence to proline-rich proteins (PRPs) in human saliva. On the basis of this feature and their shared destination in the gastrointestinal tract, we hypothesized that salivary PRPs may modulate gluten-mediated immune responses in CD. Parotid salivary secretions were collected from CD patients, refractory CD patients, non-CD patients with functional gastrointestinal complaints, and healthy controls. Structural similarities of PRPs with gluten were probed with anti-gliadin antibodies. Immune responses to PRPs were investigated toward CD patient-derived peripheral blood mononuclear cells and in a humanized transgenic HLA-DQ2/DQ8 mouse model for CD. Anti-gliadin antibodies weakly cross-reacted with the abundant salivary amylase but not with PRPs. Likewise, the R5 antibody, recognizing potential antigenic gluten epitopes, showed negligible reactivity to salivary proteins from all groups. Inflammatory responses in peripheral blood mononuclear cells were provoked by gliadins whereas responses to PRPs were similar to control levels, and PRPs did not compete with gliadins in immune stimulation. In vivo, PRP peptides were well tolerated and nonimmunogenic in the transgenic HLA-DQ2/DQ8 mouse model. Collectively, although structurally similar to dietary gluten, salivary PRPs were nonimmunogenic in CD patients and in a transgenic HLA-DQ2/DQ8 mouse model for CD. It is possible that salivary PRPs play a role in tolerance induction to gluten early in life. Deciphering the structural basis for the lack of immunogenicity of salivary PRPs may further our understanding of the toxicity of gluten.

SummaryBackgroundOlmesartan‐associated enteropathy (OAE) is characterised by diarrhoea, nausea, vomiting, abdominal pain, weight loss and severe sprue‐like enteropathy, all of which are resolved after discontinuation of olmesartan medoximil.AimTo determine the mechanistic similarities of OAE with coeliac sprue.MethodsDuodenal biopsies were extracted from OAE patients before (n = 11) or after (n = 17) discontinuation of olmesartan medoxomil (on or off olmesartan medoxomil). There were seven ‘on/off’ paired samples. Formalin‐fixed biopsies were stained for CD8, CD4, FoxP3, IL‐15R and psmad 2/3. Caco2 cells (human colonic epithelial line) were treated with olmesartan medoxomil and stained for IL‐15, IL‐15R and ZO‐1.ResultsIn the ‘on olmesartan medoxomil’ duodenal biopsies, a significant increase in the numbers of CD8+ cells and the number of cells that are FoxP3+ (a regulatory T‐cell marker) are present in the duodenum as compared to the duodenal biopsies from patients who discontinued olmesartan medoxomil. IL15R expression is also increased with olmesartan medoxomil use. Evaluation of the effect of olmesartan medoxomil upon Caco‐2 cells demonstrated that IL15 expression is increased in response to olmesartan medoxomil treatment. Further, ZO‐1, a tight junction protein, is disrupted in olmesartan medoxomil‐treated Caco‐2 cells.ConclusionsOlmesartan‐associated enteropathy shares many features with coeliac disease, including symptoms and immunopathogenic pathways, such as increased numbers of CD8+ cells and corresponding overexpression of IL15 by epithelial cells. Taken together, the treatment of epithelial cells with olmesartan medoxomil induces a response by intestinal epithelial cells that is similar to the innate effects of gluten upon the epithelium of coeliac patients.

SummaryAll vertebrates contain a diverse collection of commensal, symbiotic and pathogenic microorganisms, such as bacteria, viruses and fungi, on their various body surfaces, and the ecological community of these microorganisms is referred to as the microbiota. Mucosal sites, such as the intestine, harbour the majority of microorganisms, and the human intestine contains the largest community of commensal and symbiotic bacteria. This intestinal community of bacteria is diverse, and there is a significant variability among individuals with respect to the composition of the intestinal microbiome. Both genetic and environmental factors can influence the diversity and composition of the intestinal bacteria with the predominant environmental factor being diet. So far, studies have shown that diet‐dependent differences in the composition of intestinal bacteria can be classified into three groups, called enterotypes. Other environmental factors that can influence the composition include antibiotics, probiotics, smoking and drugs. Studies of monozygotic and dizygotic twins have proven that genetics plays a role. Recently, MHC II genes have been associated with specific microbial compositions in human infants and transgenic mice that express different HLA alleles. There is a growing list of genes/molecules that are involved with the sensing and monitoring of the intestinal lumen by the intestinal immune system that, when genetically altered, will significantly alter the composition of the intestinal microflora. The focus of this review will be on the genetic factors that influence the composition of the intestinal microflora.

Abstract The link between autoimmune diseases and primary immunodeficiency syndromes has been increasingly appreciated. Immunologic evaluation of a young man with autoimmune enterocolopathy and unexplained infections revealed evidence of immunodeficiency, including IgG subclass deficiency, impaired Ag-induced lymphocyte proliferation, reduced cytokine production by CD8+ T lymphocytes, and decreased numbers of NK cells. Genetic evaluation identified haploinsufficiency of NFAT5, a transcription factor regulating immune cell function and cellular adaptation to hyperosmotic stress, as a possible cause of this syndrome. Inhibition or deletion of NFAT5 in normal human and murine cells recapitulated several of the immune deficits identified in the patient. These results provide evidence of a primary immunodeficiency disorder associated with organ-specific autoimmunity linked to NFAT5 deficiency.

Abstract The genetic factors that contribute to the etiology of type 1 diabetes are still largely uncharacterized. However, the genes of the MHC (HLA in humans) have been consistently associated with susceptibility to disease. We have used several transgenic mice generated in our laboratory, bearing susceptible or resistant HLA alleles, in the absence of endogenous MHC class II (Aβo), to study immune responses to the autoantigen glutamic acid decarboxylase (GAD) 65 and its relevance in determining the association between autoreactivity and disease pathogenesis. Mice bearing diabetes-susceptible haplotypes, HLA DR3 (DRB1*0301) or DQ8 (DQB1*0302), singly or in combination showed spontaneous T cell reactivity to rat GAD 65, which is highly homologous to the self Ag, mouse GAD 65. The presence of diabetes-resistant or neutral alleles, such as HLA DQ6 (DQB1*0602) and DR2 (DRB1*1502) prevented the generation of any self-reactive responses to rat GAD. In addition, unmanipulated Aβo/DR3, Aβo/DQ8, and Aβo/DR3/DQ8 mice recognized specific peptides, mainly from the N-terminal region of the GAD 65 molecule. Most of these regions are conserved between human, mouse, and rat GAD 65. Further analysis revealed that the reactivity was mediated primarily by CD4+ T cells. Stimulation of these T cells by rat GAD 65 resulted in the generation of a mixed Th1/Th2 cytokine profile in the Aβo/DR3/DQ8, Aβo/DR3, and Aβo/DQ8 mice. Thus, the presence of diabetes-associated genes determines whether immune tolerance is maintained to islet autoantigens, but autoreactivity in itself is not sufficient to induce diabetes.