Intraepithelial lymphocytes in celiac disease

A new algorithm for coeliac disease based on the 'long forgotten' TCRγδ+ intra-epithelial lymphocytes detected with an antibody working on FFPE sections

AIMS

Diagnosis of coeliac disease (CD) with mild mucosal changes is difficult for all parties involved. We aimed to determine the power of T cell receptor (TCR)γδ+ intra-epithelial lymphocytes (IELs) in discriminating CD from other causes of intra-epithelial lymphocytosis using a new monoclonal antibody.

METHODS

A total of 167 cases categorised as coeliac (117 untreated CD, classified according to Marsh, updated by Ensari, including 29 type 1, 29 type 2, 39 type 3 and 20 treated CD), and non-coeliac groups (24 controls and 26 non-coeliac IELosis) based on clinical, serological and histological data were studied for IEL counts enumerated per 100 enterocytes using haematoxylin and eosin, CD3, TCR δ-stains.

RESULTS

TCRγδ+ IELs were significantly higher in CD (24.83 ± 16.13) compared to non-CD (6.72 ± 6.32) and were correlated with the degree of mucosal damage. Both γδ+ IEL count and ratio showed higher performance in differentiating untreated coeliacs from controls, with a sensitivity of 83.76; 85.57 and specificity of 95.83; 79.17, respectively. TCRγδ+ IEL counts distinguished type 1 CD (20.41 ± 13.57) from non-coeliac IELosis (9.42 ± 7.28) (p = 0.025). Discriminant analysis revealed that villus/crypt ratio, γδ+ and CD3+ IEL counts, γδ+/CD3+IEL ratio, IEL distribution pattern were potent discriminants and correctly classified 82.3% of cases while the algorithm accurately diagnosed 93.4% of cases.

CONCLUSIONS

The new antibody detecting γδ+ IELs in FFPE sections revealed thresholds of 10.5 for γδ+ IELs and 14% for γδ+/CD3+IEL ratio which distinguished coeliacs from non-coeliacs with high sensitivity and specificity, particularly in cases with normal villus/crypt axis including type 1 CD, non-CD IELosis and controls. A 'coeliac algorithm' based on γδ+ IELs is proposed with the hope that it will be used in the histopathological diagnostic approach by the pathology community.

Celiac disease, non-celiac wheat sensitivity, wheat allergy - clinical and diagnostic aspects

In recent years, wheat- and gluten-free diets have increased in demand due to reported increases in various conditions reported to be driven by ingredients of these food products. Celiac disease, wheat allergy and non-celiac wheat sensitivity constitute the three main categories of wheat-related disorders. Celiac disease is a well-characterized immune-mediated disease caused by immune reaction against specific gliadin epitopes, the main protein in wheat. Screening studies of samples collected over time bring evidence that there is a true increase in prevalence not only driven by increased testing activity. Clinical presentation of CeD is diverse and there is an increased risk of autoimmune co-morbidities. Wheat allergy consists of IgE- and non-IgE-mediated reactions, driven by Th2-cells directing eosinophil and basophil responses. Rapid IgE-mediated reactions are characterized by specific IgE antibodies in conjunction with symptoms originating especially from the respiratory and gastrointestinal tract. There is an increased risk of other allergies and the majority recover during adolescence. Non-IgE-mediated wheat allergy is a less-well defined condition, which is often diagnostically challenging due to a longer interval between exposure and symptoms and lack of non-invasive biomarkers. In this condition, wheat as a trigger needs to be established by exclusion followed by dietary challenge. Non-celiac wheat sensitivity, despite being the most recently recognized, has the highest reported prevalence among the three wheat-related entities. It remains, however, particularly poorly characterized due to unclear pathophysiology and lack of diagnostic markers. This narrative review will scrutinize the shared and distinct clinical features of the three wheat-related conditions, focusing on epidemiology, clinical presentation, co-morbidities, diagnosis, treatment and prognosis.

American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease

This guideline presents an update to the 2013 American College of Gastroenterology Guideline on the Diagnosis and Management of Celiac Disease with updated recommendations for the evaluation and management of patients with celiac disease (CD). CD is defined as a permanent immune-mediated response to gluten present in wheat, barley, and rye. CD has a wide spectrum of clinical manifestations that resemble a multisystemic disorder rather than an isolated intestinal disease, and is characterized by small bowel injury and the presence of specific antibodies. Detection of CD-specific antibodies (e.g., tissue transglutaminase) in the serum is very helpful for the initial screening of patients with suspicion of CD. Intestinal biopsy is required in most patients to confirm the diagnosis. A nonbiopsy strategy for the diagnosis of CD in selected children is suggested and discussed in detail. Current treatment for CD requires strict adherence to a gluten-free diet (GFD) and lifelong medical follow-up. Most patients have excellent clinical response to a GFD. Nonresponsive CD is defined by persistent or recurrent symptoms despite being on a GFD. These patients require a systematic workup to rule out specific conditions that may cause persistent or recurrent symptoms, especially unintentional gluten contamination. Refractory CD is a rare cause of nonresponsive CD often associated with poor prognosis.

Significance of low ferritin without anaemia in screen-detected, adult coeliac disease patients

BACKGROUND

Low ferritin without anaemia has been linked to adverse health effects.

OBJECTIVES

To investigate the prevalence and clinical significance of low ferritin in screen-detected coeliac disease.

METHODS

Seventy-six screen-detected coeliac disease patients were enrolled in the prospective collection of comprehensive clinical, laboratory and histological data at diagnosis and after 1-2 years on a gluten-free diet (GFD). All variables were compared between patients with different ferritin levels.

RESULTS

At coeliac disease diagnosis, six patients had anaemia. Of the 70 nonanaemic patients, ferritin levels were <15 μg/L in 21%, 15-29 μg/L in 19%, 30-99 μg/L in 36% and ≥100 μg/L in 24%. Those with lower ferritin were more often females, had lower body mass index, haemoglobin and villous height-crypt depth ratio and also had higher intra-epithelial lymphocyte CD3+ levels in duodenal biopsies. The groups did not differ in neurological or gastrointestinal symptoms, health-related quality of life, bone mineral density, liver values, vitamin, albumin or coeliac autoantibody levels or the prevalence of comorbidities. Median ferritin levels increased from 41.5 μg/L to 86.0 μg/L on GFD (p < 0.001). Ferritin remained <30 μg/L in 21% of patients but was not associated with dietary compliance, nor was any correlation between changes in ferritin and quality of life, gastrointestinal symptoms, autoantibody levels or degree of histological damage detected.

CONCLUSION

Decreased ferritin is a frequent finding in screen-detected coeliac disease and may not be fully restored on a GFD. However, low ferritin levels are not associated with more severe symptoms or poorer quality of life.

Mucosal Healing in Celiac Disease: Villous Architecture and Immunohistochemical Features in Children on a Long-Term Gluten Free Diet

Considerable heterogeneity exists across studies assessing intestinal mucosal recovery in celiac (CD) patients on a gluten-free diet (GFD). We aimed at investigating histological and immunohistochemical features in CD patients on a long-term GFD and to correlate them to the GFD duration. Morphometrical and immunohistochemical analysis were retrospectively performed on duodenal biopsies in three groups of children: 33 on a long-term (>2 years) GFD (GFD-group), four of which remained seropositive despite dietary adherence, 31 with villous atrophy (ACD-group) and 76 heathy, non-celiac (CTR-group). Moreover, in the GFD-group, we correlated immunohistochemical alterations to the GFD duration. The villous to crypt (V/C) ratio significantly improved after the GFD and completely normalized in all patients, becoming even higher than in the CTR-group (median value 3.2 vs. 3, p = 0.007). In parallel, the number of CD3+ and TCRγδ+ cells in the epithelium were significantly reduced in the GFD compared to ACD patients, even if they remained higher than in the CTR-group (p < 0.05). In contrast, CD25+ cells in the lamina propria significantly decreased after the GFD (p < 0.05) and become comparable to the CTR-group (p = 0.9). In the GFD-group there was no difference in the immunohistochemical parameters between seropositive and seronegative patients and alterations did not correlate to GFD length. In conclusion, a GFD is able to both restore a normal V/C ratio and reduce inflammation, but the epithelium maintains some stigmata of the disorder, such as an increased number of CD3+ and TCRγδ+ cells. These alterations persist regardless of the duration of the GFD.

Ultra-short celiac disease exhibits differential genetic and immunophenotypic features compared to conventional celiac disease

BACKGROUND

Ultra-short coeliac disease (USCD) is a novel celiac disease (CD) subtype limited to the duodenal bulb (D1). HLA haplotypes and flow cytometry have not been assessed yet.

AIMS

To compare genetic, clinical, serologic, histopathologic and inmmunophenotypic parameters between USCD and conventional celiac disease (CCD) patients.

METHODS

Prospective single-center study in children and adult patients undergoing duodenal biopsies on a gluten-containing diet. Biopsies for histology and flow cytometry were taken separately from D1 and distal duodenum. Biopsies in seronegative patients with celiac lymphogram were repeated after 2 years on a gluten-free diet.

RESULTS

Among 505 included patients, 127 were diagnosed with CD, of whom 7 (5.5%) showed USCD. HLADQ2 was significantly less common in USCD compared to CCD (71% vs. 95%, p 0.003). Likewise, USCD patients showed more frequent non-significant seronegativity (28% vs. 8%, p 0.07) and significantly lower titrations (7-15 IU/ml) of tissue transglutaminase antibodies (tTG-IgA) (60% vs. 13%, p<0.001). Biopsies from D1 revealed significant less NK cells down-expression in USCD patients (1.4 vs. 5, p 0.04).

CONCLUSIONS

Up to 5.5% of CD patients showed USCD. A lower frequency of HLADQ2, along with less serum tTG-IgA titration and duodenal NK cell suppression, were differential features of USCD.

Intraepithelial Lymphocyte Cytometric Pattern Is a Useful Diagnostic Tool for Coeliac Disease Diagnosis Irrespective of Degree of Mucosal Damage and Age-A Validation Cohort

Introduction: The study of intraepithelial lymphocytes (IEL) by flow cytometry is a useful tool in the diagnosis of coeliac disease (CD). Previous data showed that an increase in %TCRγδ⁺ and decrease of %CD3⁻ IEL constitute a typical CD cytometric pattern with a specificity of 100%. However, there are no data regarding whether there are differences in the %TCRγδ⁺ related to sex, age, titers of serology, and degree of histological lesion. Study aims: To confirm the high diagnostic accuracy of the coeliac cytometric patterns. To determine if there are differences between sex, age, serology titers, and histological lesion grade. Results: We selected all patients who fulfilled “4 of 5” rule for CD diagnosis (n = 169). There were no differences in %TCRγδ⁺ between sexes (p = 0.909), age groups (p = 0.986), serology titers (p = 0.53) and histological lesion grades (p = 0.41). The diagnostic accuracy of complete CD cytometric pattern was: specificity 100%, sensitivity 82%, PPV 100%, NPV 47%. Conclusion: We confirmed, in a validation cohort, the high diagnostic accuracy of complete CD pattern irrespective of sex, age, serology titers, and grade of mucosal lesion.

Missing Insight Into T and B Cell Responses in Dermatitis Herpetiformis

Dermatitis herpetiformis is a cutaneous form of celiac disease manifesting as an itching rash typically on the elbows, knees and buttocks. It is driven by the ingestion of gluten-containing cereals and characterized by granular deposits of immunoglobulin A in the papillary dermis. These antibodies target transglutaminase (TG) 3 and in the majority of patients they are also found in circulation. The circulating antibodies disappear and skin symptoms resolve as a result of gluten-free diet but the cutaneous anti-TG3 IgA deposits may persist for several years. In dermatitis herpetiformis, plasma cells secreting antibodies against TG3 are located in the intestinal mucosa similarly to those producing TG2 antibodies characteristic for celiac disease. In fact, both TG2- and TG3-specific plasma cells and gluten responsive T cells are found in dermatitis herpetiformis patients but the interplay between these cell populations is unknown. The small bowel mucosal damage in celiac disease is believed to be mediated by co-operation of cytotoxic intraepithelial T cells and the inflammatory milieu contributed by gluten-reactive CD4+ T cells, whereas the skin lesions in dermatitis herpetiformis appear to be devoid of gluten reactive T cells. Thus, how celiac disease-type intestinal T and B cell responses develop into an autoimmune condition affecting the skin is still incompletely understood. Finally, the skin and small bowel lesions may reappear upon reintroduction of gluten in patients treated with gluten-free diet but virtually nothing is known about the long-lived B cell and memory T cell populations activating in response to dietary gluten in dermatitis herpetiformis.

A New Intraepithelial γδ T-Lymphocyte Marker for Celiac Disease Classification in Formalin-Fixed Paraffin-Embedded (FFPE) Duodenal Biopsies

BACKGROUND

The histopathologic diagnosis of celiac disease (CD) may be challenging when the duodenal biopsies mucosal injury is limited. Intraepithelial T-lymphocytes (IELs) can be useful to characterize the degree of mucosal inflammation. A small fraction of IELs expresses the γδ T-cell receptor (named γδ-IELs), whose density, determined by flow cytometry or frozen section immunohistochemistry (IHC), is a specific marker for CD.

AIM

To establish a new IHC assay for γδ-IELs applicable to formalin-fixed paraffin-embedded (FFPE) duodenal biopsies.

METHODS

We analyzed γδ-IELs using IHC in 138 duodenal biopsies using a standard IHC staining protocol with a new monoclonal antibody H-41. IELs were quantitated with digital image analysis.

RESULTS

Compared to those in non-celiac controls (n = 51), γδ-IEL density was significantly increased in newly diagnosed celiac disease patients (n = 22, p < 0.0001). In ROC-curve analysis, the cutoff of 6.5 γδ-IELs/100 enterocytes distinguished optimally active CD patients from non-celiac controls (sensitivity 96%, specificity 95%). γδ-IEL density in CD patients on a gluten-free diet (n = 53) were also higher than in controls (p < 0.0001), but lower than those in newly diagnosed CD (p < 0.0001). The diagnostic value of γδ-IELs outperformed that of CD3 + IELs in both patient groups. γδ-IELs were better than CD3 + IELs distinguishing between celiac disease and conditions histologically mimicking celiac disease (n = 12).

CONCLUSIONS

Intraepithelial γδ T-lymphocytes can be stained and quantitated reliably in FFPE duodenal biopsies. The results showed excellent specificity and sensitivity for celiac disease. The new IHC method of detection of γδ-IELs is a promising addition to the routine histopathologic assessment methodology of celiac disease.

Hypersensitivities following allergen antigen recognition by unconventional T cells

Conventional T cells recognise protein-derived antigens in the context of major histocompatibility complex (MHC) class Ia and class II molecules and provide anti-microbial and anti-tumour immunity. Conventional T cells have also been implicated in type IV (also termed delayed-type or T cell-mediated) hypersensitivity reactions in response to protein-derived allergen antigens. In addition to conventional T cells, subsets of unconventional T cells exist, which recognise non-protein antigens in the context of monomorphic MHC class I-like molecules. These include T cells that are restricted to the cluster of differentiation 1 (CD1) family members, known as CD1-restricted T cells, and mucosal-associated invariant T cells (MAIT cells) that are restricted to the MHC-related protein 1 (MR1). Compared with conventional T cells, much less is known about the immune functions of unconventional T cells and their role in hypersensitivities. Here, we review allergen antigen presentation by MHC-I-like molecules, their recognition by unconventional T cells, and the potential role of unconventional T cells in hypersensitivities. We also speculate on possible scenarios of allergen antigen presentation by MHC-I-like molecules to unconventional T cells, the hallmarks of such responses, and the expected frequencies of hypersensitivities within the human population.

Non-Biopsy Serology-Based Diagnosis of Celiac Disease in Adults Is Accurate with Different Commercial Kits and Pre-Test Probabilities

Non-biopsy diagnosis of celiac disease is possible in children with anti-transglutaminase 2 antibodies (TGA) > 10× the upper limit of normal (ULN) and positive anti-endomysial antibodies (EMA). Similar criteria have been suggested for adults, but evidence with different TGA assays is scarce. We compared the performance of four TGA tests in the diagnosis of celiac disease in cohorts with diverse pre-test probabilities. Serum samples from 836 adults with either clinical suspicion or family risk of celiac disease were tested with four commercial TGA assays, EmA and celiac disease-associated genetics. The diagnosis was set based on duodenal lesion or, in some cases, using special methods. 137 (57%) patients with clinical suspicion and 85 (14%) of those with family risk had celiac disease. Positive predictive value (PPV) for 10×ULN was 100% in each TGA test. The first non-diagnostic investigations were encountered with ULN 1.0×–5.1× in the clinical cohort and 1.3×–4.9× in the family cohort, respectively. Using the assays’ own cut-offs (1×ULN) the PPVs ranged 84–100%. Serology-based diagnosis of celiac disease was accurate in adults using different commercial kits and pre-test probabilities using 10×ULN. The results also suggest that the ULN threshold for biopsy-omitting approach could be lower.

Serum Level and Gene Expression of Interleukin-15 Do Not Correlate with Villous Atrophy in Celiac Disease Patients

Background and Aims: Interleukin-15 (IL-15) is a key player in the pathogenesis of celiac disease (CD). We investigated the functional role of IL-15 in the process of epithelial cell phenotypic modification at different stages of CD. Materials and Methods: In this study, we looked for correlations between the IL-15 mRNA levels in duodenal tissue and serum protein levels in a cohort of Iranian patients affected by CD based on the degree of histopathology. Ninety-five formalin-fixed, paraffin-embedded duodenal tissue specimens were collected: 23 with a Marsh I value; 30 with a Marsh II value; 32 with a Marsh III value; and 10 normal controls. The expression levels of the IL-15 gene in these biopsy specimens were determined by real-time quantitative polymerase chain reaction (qPCR), and IL-15 serum protein concentrations were determined by enzyme-linked immunosorbent assay and compared to tissue expression. Results: The IL-15 mRNA levels were higher in patients with Marsh II compared with the control group, and the Marsh I, and Marsh III groups. The differences between the Marsh II and Marsh I patients were statistically significant (p = 0.03). Similarly, the serum concentration of IL-15 was higher in Marsh II patients compared to those with Marsh I and Marsh III lesions, although the differences were not statistically significant (p = 0.221). Conclusions: Our results demonstrate that IL-15 gene expression might be elevated only in the early stages of CD onset (and histological damage) and that IL-15 serum levels do not significantly correlate with its tissue expression whatever the degree of histopathology.

Prevalence and diagnostic outcomes of children with duodenal lesions and negative celiac serology

BACKGROUND

Celiac disease diagnostics begin by measuring autoantibodies, which may fail to identify seronegative patients. Duodenal lesion in the absence of antibodies is scarcely studied, especially in children.

AIMS

To investigate the prevalence and diagnostic outcomes of children with seronegative duodenal lesion in two countries with different disease profiles.

METHODS

Medical data, including the results of histology and transglutaminase (tTGab) and endomysium (EmA) antibody measurements were collected from 1172 Finnish and 264 Romanian children with systematic duodenal sampling. Database of 509 Finnish children with celiac disease was examined to identify earlier seronegative patients.

RESULTS

Celiac disease was diagnosed in 307 Finnish and 83 Romanian children in the endoscopy cohorts. No seronegative patients were found among 899 celiac disease patients, although some were only tTGab or EmA positive. Non-celiac duodenal lesion was detected in eight Finnish and 32 Romanian children, their most common diagnoses being inflammatory bowel disease and infections, respectively. Six children with morphological lesion received no diagnosis. None of them developed celiac disease during a follow-up of 3-11 years.

CONCLUSION

Pediatric seronegative celiac disease is exceptional in the era of modern autoantibodies. Other reasons for duodenal lesion should therefore be sought, bearing in mind possible differences across countries.

Intestinal TG3- and TG2-Specific Plasma Cell Responses in Dermatitis Herpetiformis Patients Undergoing a Gluten Challenge

Dermatitis herpetiformis (DH), a cutaneous manifestation of coeliac disease, is characterized by transglutaminase (TG) 3-targeted dermal immunoglobulin A (IgA) deposits. The treatment for DH is the same as for coeliac disease, namely a life-long gluten-free diet. DH patients typically have gluten-dependent circulating autoantibodies targeting TG3 and TG2, and plasma cells secreting such autoantibodies have been detected in the small intestinal mucosa. This study investigates the gluten-responsiveness of intestinal TG3 and TG2 antibody-secreting plasma cells in 16 treated DH patients undergoing a gluten challenge. The frequency of both plasma cell populations increased significantly during the challenge, and their frequency correlated with the corresponding serum autoantibody levels at post-challenge. TG3-specific plasma cells were absent in all 18 untreated coeliac disease patients and seven non-coeliac control subjects on gluten-containing diets. These findings indicate that, in DH, both intestinal TG3- and TG2-antibody secreting plasma cells are gluten-dependent, and that TG3-antibody secreting plasma cells are DH-specific.

Histological, immunohistochemical and mRNA gene expression responses in coeliac disease patients challenged with gluten using PAXgene fixed paraffin-embedded duodenal biopsies

Background

There is an unmet need for novel treatments, such as drugs or vaccines, adjunctive to or replacing a burdensome life-long gluten-free diet for coeliac disease. The gold standard for successful treatment is a healed small intestinal mucosa, and therefore, the outcome measures in proof-of-concept studies should be based on evaluation of small intestine biopsies. We here evaluated morphometric, immunohistochemical and messenger RNA (mRNA) expression changes in coeliac disease patients challenged with gluten using PAXgene fixed paraffin-embedded biopsies.

Methods

Fifteen coeliac disease patients were challenged with 4 g of gluten per day for 10 weeks and 24 non-coeliac patients served as disease controls. A wide array of histological and immunohistochemical staining and mRNA-based gene expression tests (RT-qPCR and RNAseq) were carried out.

Results

Digital quantitative villous height: crypt depth ratio (VH: CrD) measurements revealed significant duodenal mucosal deterioration in all coeliac disease patients on gluten challenge. In contrast, the Marsh-Oberhuber class worsened in only 80% of coeliac patients. Measuring the intraepithelial CD3⁺ T-lymphocyte and lamina propria CD138⁺ plasma cell densities simultaneously proved to be a meaningful new measure of inflammation. Stainings for γδ T cells and IgA deposits, where previously frozen samples have been needed, were successful in PAXgene fixed paraffin-embedded samples. Messenger RNA extraction from the same paraffin-embedded biopsy block was successful and allowed large-scale qRT-PCR and RNAseq analyses for gene expression. Molecular morphometry, using the mRNA expression ratio of villous epithelium-specific gene APOA4 to crypt proliferation gene Ki67, showed a similar significant distinction between paired baseline and post-gluten challenge biopsies as quantitative histomorphometry.

Conclusion

Rigorous digitally measured histologic and molecular markers suitable for gluten challenge studies can be obtained from a single paraffin-embedded biopsy specimen. Molecular morphometry seems to be a promising new tool that can be used in situations where assessing duodenal mucosal health is of paramount importance. In addition, the diagnostically valuable IgA deposits were now stained in paraffin-embedded specimens making them more accessible in routine clinics.

The Challenge of Treatment in Potential Celiac Disease

Potential celiac disease (PCD) is defined by the presence of positive serum antibodies, HLA-DQ2/DQ8 haplotypes, and a normal small intestinal mucosa (Marsh grade 0-1). This condition occurs in one-fifth of celiac disease (CD) patients and usually represents a clinical challenge. We reviewed genetic, histologic, and clinical features of this specific condition by performing a systematic search on MEDLINE, Embase, and Scholar database. Accordingly, we identified different genetic features in patients with PCD compared to the classical forms. Frequently, signs of inflammation (deposits of immunoglobulin A (IgA) and/or increased number of intraepithelial lymphocytes) can be clearly identify in the mucosa of PCD patients after an accurate histological assessment. Finally, the main challenge is represented by the treatment: the gluten-free diet should be considered only in the presence of gluten-dependent symptoms in both children and adults. What is known: (i) potential celiac disease (PCD) occurs in one-fifth of all celiac diseases (CD), and (ii) despite the absence of classical lesions, clear signs of inflammation are often detectable. What is new: (i) patients with PCD show different genetic features, and (ii) the presence of gluten-dependent symptoms is the main determinant to initiate the gluten-free diet, after a complete diagnostic work-up.

The intestinal expansion of TCRγδ+ and disappearance of IL4+ T cells suggest their involvement in the evolution from potential to overt celiac disease

Celiac disease (CD) is characterized by a spectrum of intestinal inflammatory lesions. Most patients have villous atrophy (overt-CD), while others have a morphologically normal mucosa, despite the presence of CD-specific autoantibodies (potential-CD). As the mechanism responsible for villous atrophy is not completely elucidated, we investigated biomarkers specific for the different celiac lesions. Phenotype and cytokine production of intestinal mucosa cells were analyzed by flow cytometry in gut biopsies of children with overt- or potential-CD and in healthy controls. Density of TCRγδ⁺ T cells was found markedly enhanced in intestinal mucosa of children with overt-CD compared to potential-CD or controls. By contrast, very few IL4⁺ T cells infiltrated the mucosa with villous atrophy compared to morphologically normal mucosa. IL4⁺ T cells were classical CD4⁺ T-helper cells (CD161^- ), producing or not IFN-γ, and negative for IL17A. Our study demonstrated that the transition to villous atrophy in CD patients is characterized by increased density of TCRγδ⁺ T cells, and concomitant disappearance of IL4⁺ cells. These findings suggest that immunomodulatory mechanisms are active in potential-CD to counteract the inflammatory cascade responsible of villous atrophy. Further studies are required to validate the use of IL4⁺ and TCRγδ⁺ T cells as biomarkers of the different CD forms.

Systematic Review and Meta-Analysis: Accuracy of Both Gamma Delta+ Intraepithelial Lymphocytes and Coeliac Lymphogram Evaluated by Flow Cytometry for Coeliac Disease Diagnosis

It has been suggested that in doubtful cases of coeliac disease, a high CD3+ T-cell receptor gamma delta+ (TCRγδ+) intraepithelial lymphocyte count increases the likelihood of coeliac disease.

AIM

To evaluate the diagnostic accuracy of both an isolated increase of TCRγδ+ cells and a coeliac lymphogram (increase of TCRγδ+ plus decrease of CD3- intraepithelial lymphocytes) evaluated by flow cytometry in the diagnosis of coeliac disease.

METHODS

The literature search was conducted in MEDLINE and EMBASE. The inclusion criteria were: an article that allows for the construction of a 2 × 2 table of true and false positive and true and false negative values. A diagnostic accuracy test meta-analysis was performed.

RESULTS

The search provided 49 relevant citations, of which 6 were selected for the analysis, which represented 519 patients and 440 controls. Coeliac lymphogram: The pooled S and Sp were 93% and 98%, without heterogeneity. The area under the SROC curve (AUC) was 0.98 (95% CI, 0.97-0.99). TCRγδ+: Pooled S and Sp were both 95%, with significant heterogeneity. The AUC was 0.97 (95% CI, 0.95-0.98). Conclusions: Both TCRγδ+ count and coeliac lymphogram assessed by flow cytometry in duodenal mucosal samples are associated with a high level of diagnostic accuracy for and against coeliac disease.

Dietary Factors and Mucosal Immune Response in Celiac Disease Patients Having Persistent Symptoms Despite a Gluten-free Diet

GOALS

The aim of this study was to investigate the role of dietary factors, distinct small-bowel mucosal immune cell types, and epithelial integrity in the perpetuation of gastrointestinal symptoms in treated celiac disease patients.

BACKGROUND

For unexplained reasons, many celiac disease patients suffer from persistent symptoms, despite a strict gluten-free diet (GFD) and recovered intestinal mucosa.

STUDY

We compared clinical and serological data and mucosal recovery in 22 asymptomatic and 25 symptomatic celiac patients on a long-term GFD. The density of CD3 and γδ intraepithelial lymphocytes (IELs), CD25 and FOXP3 regulatory T cells, and CD117 mast cells, and the expression of tight junction proteins claudin-3 and occludin, heat shock protein 60, interleukin 15, and Toll-like receptor 2 and 4 were evaluated in duodenal biopsies.

RESULTS

All subjects kept a strict GFD and had negative celiac autoantibodies and recovered mucosal morphology. The asymptomatic patients had higher mean fiber intake (20.2 vs. 15.2 g/d, P=0.028) and density of CD3 IELs (59.3 vs. 45.0 cell/mm, P=0.045) than those with persistent symptoms. There was a similar but nonsignificant trend in γδ IELs (17.9 vs. 13.5, P=0.149). There were no differences between the groups in other parameters measured.

CONCLUSIONS

Low fiber intake may predispose patients to persistent symptoms in celiac disease. There were no differences between the groups in the markers of innate immunity, epithelial stress or epithelial integrity. A higher number of IELs in asymptomatic subjects may indicate that the association between symptoms and mucosal inflammation is more complicated than previously thought.

A Scoring System for Identifying Patients Likely to Be Diagnosed with Low-Grade Coeliac Enteropathy

BACKGROUND & AIMS

Determining whether patients with lymphocytic enteritis (LE) have coeliac disease is a challenge. We analysed the variables associated with a low-grade coeliac enteropathy diagnosis in patients with suspected coeliac disease but without villous atrophy, and developed a scoring system to identify them.

METHODS

We collected data from 2010 through to 2016 on patients with lymphocytic enteritis and persistent symptoms compatible with the clinical spectrum of coeliac disease. One hundred and four patients starting on a gluten-free diet (GFD) were included. Duodenal biopsies were collected before the GFD and analysed for numbers of CD3⁺ T-cell receptor gamma delta+ (TCRγδ⁺), and CD3^- intraepithelial lymphocytes. We performed a logistic regression analysis to identify factors associated with a low-grade coeliac enteropathy diagnosis.

RESULTS

Sixty-two patients achieved clinical remission after the GFD. Fifty of these 62 patients were diagnosed with low-grade coeliac enteropathy. Multivariate analysis identified the presence of >25% intraepithelial lymphocytosis, HLA-DQ2.5, positive serology, and increased numbers of TCRγδ⁺ cells with a low-grade coeliac enteropathy diagnosis. We developed a scoring system that identified patients with an area under the ROC curve (AUC) of 0.91. Scores of >10 had 86% sensitivity and 85% specificity.

CONCLUSION

We developed a scoring system that identifies patients likely to be diagnosed with low-grade coeliac enteropathy with an AUC value of 0.91.

Gamma-Delta T Lymphocytes in the Diagnostic Approach of Coeliac Disease

GOALS

To validate cut-off values of CD3 T-cell receptor gamma-delta chain (TCRγδ) intraepithelial lymphocyte (IEL) in the (differential) diagnosis of celiac disease (CD).

BACKGROUND

CD is characterized by an increase in gamma-delta IEL (CD3TCRγδ IEL).

STUDY

Percentages were determined by flow cytometric analysis of IELs from small bowel biopsies in 213 CD and 13 potential CD (PCD) patients and in total 112 controls. A cut-off value for percentages of CD3TCRγδ IEL to differentiate active CD and controls was obtained from a receiver operating characteristic curve and implemented in controls and PCD patients.

RESULTS

Percentage of CD3TCRγδ IEL was significantly increased in the majority of CD patients, irrespective of the presence of villous atrophy. A cut-off value of 14% for CD3TCRγδ IEL resulted in 66.3% sensitivity and 96.6% specificity for CD diagnosis (area under the curve, 88.6%).

CONCLUSIONS

A percentage of ≥14% CD3TCRγδ IEL has a high specificity for CD diagnosis and can be of diagnostic help in cases where diagnosis is not straightforward.

Gluten Challenge Induces Skin and Small Bowel Relapse in Long-Term Gluten-Free Diet-Treated Dermatitis Herpetiformis

Dermatitis herpetiformis (DH) is an extraintestinal manifestation of celiac disease causing an itchy, blistering rash. Granular IgA deposits in the skin are pathognomonic for DH, and the treatment of choice is a lifelong gluten-free diet (GFD). Preliminary evidence suggests that there are patients with DH who redevelop gluten tolerance after adherence to a GFD treatment. To evaluate this, we performed a 12-month gluten challenge with skin and small-bowel mucosal biopsy samples in 19 patients with DH who had adhered to a GFD for a mean of 23 years. Prechallenge biopsy was negative for skin IgA and transglutaminase 3 deposits in 16 patients (84%) and indicated normal villous height-to-crypt depth ratios in the small bowel mucosa in all 19 patients. The gluten challenge caused a relapse of the rash in 15 patients (79%) in a mean of 5.6 months; of these 15 patients, 13 had skin IgA and transglutaminase 3 deposits, and 12 had small-bowel villous atrophy. In addition, three patients without rash or immune deposits in the skin developed villous atrophy, whereas one patient persisted without any signs of relapse. In conclusion, 95% of the patients with DH were unable to tolerate gluten even after long-term adherence to a GFD. Therefore, lifelong GFD treatment remains justified in all patients with DH.

Small-intestinal TG2-specific plasma cells at different stages of coeliac disease

Background

In coeliac disease, ingestion of gluten induces the production of transglutaminase 2 (TG2)-targeted autoantibodies by TG2-specific plasma cells present at high frequency in the small intestinal mucosa in untreated disease. During treatment with a gluten-free diet (GFD), the number of these cells decreases considerably. It has not been previously investigated whether the cells are also present prior to development of villous atrophy, or in non-responsive patients and those with dietary lapses. We aimed to define the frequency of small bowel mucosal TG2-specific plasma cells in coeliac disease patients with varying disease activity, and to investigate whether the frequency correlates with serum and small intestinal TG2-targeting antibodies as well as mucosal morphology and the number of intraepithelial lymphocytes.

Results

Mucosal TG2-specific plasma cells were found in 79% of patients prior to development of mucosal damage, in all patients with villous atrophy, and in 63% of the patients after 1 year on GFD. In these disease stages, TG2-specific plasma cells accounted for median of 2.3, 4.3, and 0.7% of all mucosal plasma cells, respectively. After long-term treatment, the cells were present in 20% of the patients in clinical remission (median 0%) and in 60% of the patients with poor dietary adherence (median 5.8%). In patients with non-responsive coeliac disease despite strict GFD, the cells were found in only one (9%) subject; the cells accounted for 2.4% of all plasma cells. A positive correlation between the percentage of TG2-specific plasma cells and serum TG2 antibody levels (r_S = 0.69, P < 0.001) and the intensity of mucosal TG2-targeting IgA deposits (r_S = 0.43, P < 0.001) was observed.

Conclusions

Our results show that TG2-specific plasma cells are already detectable prior to villous atrophy, and that generally their frequency increases during overt disease. By contrast, on GFD, the percentage of these cells decreases. Overall, the presence of TG2-specific plasma cells in the small bowel mucosa mirrors the presence of gluten in the diet, but the frequency is not always parallel to the level of serum or intestinal TG2 antibodies. These findings increase the knowledge about the development of the TG2 plasma cell responses especially in the early phases of coeliac disease.

Electronic supplementary material

The online version of this article (10.1186/s12865-018-0275-7) contains supplementary material, which is available to authorized users.

Microbial Biomarkers in Patients with Nonresponsive Celiac Disease

BACKGROUND AND AIMS

In nonresponsive celiac disease (NRCD), the symptoms and duodenal damage persist despite a gluten-free diet. Celiac disease patients with persistent symptoms are found to have a dysbiotic microbiota. We thus hypothesized that increased seroreactivity to the serum gluten-sensitive microbial antibodies Saccharomyces cerevisiae (ASCA), Pseudomonas fluorescens-associated sequence (I2), and Bacteroides caccae TonB-linked outer membrane protein (OmpW) is associated with NRCD.

METHODS

ASCA, I2 and OmpW were measured in 20 seronegative CD patients with persistent villous damage despite strict dietary treatment (NRCD group). Fifty-eight responsive patients served as CD controls (55 on gluten-free treatment) and 80 blood donors as non-CD controls.

RESULTS

At least one microbial marker was positive in 80% of NRCD patients, in 97% of untreated CD and 87% of treated CD patients, and in 44% of controls. NRCD patients had the highest frequency of ASCA positivity (65% vs 52, 20, and 0%, respectively) and also significantly higher ASCA IgA (median 14.5 U/ml) and IgG (32.5 U/ml) titers than treated CD patients (7.0 U/ml, 13.0 U/ml) and non-CD controls (4.5 U/ml, 5.8 U/ml). The frequencies of I2 and OmpW were lower in NRCD than in untreated CD (65% and 45% vs 86% and 59%, respectively), and I2 titers were higher in NRCD (median absorbance 0.76) and untreated (1.0) and treated (0.83) CD than controls (0.32). OmpW was elevated in untreated (1.1) and treated (0.94) CD patients compared with controls (0.79).

CONCLUSIONS

Seropositivity and high titers of ASCA are associated with NRCD and might serve as an additional follow-up tool in CD.

The elusive case of human intraepithelial T cells in gut homeostasis and inflammation

The epithelial barrier of the gastrointestinal tract is home to numerous intraepithelial T cells (IETs). IETs are functionally adapted to the mucosal environment and are among the first adaptive immune cells to encounter microbial and dietary antigens. They possess hallmark features of tissue-resident T cells: they are long-lived nonmigratory cells capable of rapidly responding to antigen challenges independent of T cell recruitment from the periphery. Gut-resident T cells have been implicated in the relapsing and remitting course and persisting low-grade inflammation of chronic gastrointestinal diseases, including IBD and coeliac disease. So far, most data IETs have been derived from experimental animal models; however, IETs and the environmental makeup differ between mice and humans. With advances in techniques, the number of human studies has grown exponentially in the past 5 years. Here, we review the literature on the involvement of human IETs in gut homeostasis and inflammation, and how these cells are influenced by the microbiota and dietary antigens. Finally, targeting of IETs in therapeutic interventions is discussed. Broad insight into the function and role of human IETs in gut homeostasis and inflammation is essential to identify future diagnostic, prognostic and therapeutic strategies.

Celiac Disease Autoimmunity

Celiac disease is an autoimmune condition triggered by the ingestion of gluten, the protein fraction of wheat, barley and rye. It is not simply an intestinal disease; it is multifactorial caused by many different genetic factors acting together with non-genetic causes. Similar to other autoimmune diseases, celiac disease is a polygenic disorder for which the major histocompatibility complex locus is the most important genetic factor, and is the result of an immune response to self-antigens leading to tissue destruction and the autoantibodies production. Celiac disease exemplifies how an illness can have autoimmune-like features having to be driven by exogenous antigen and how can be reasonably considered as a model of organ-specific autoimmunity.

Outcome measures in coeliac disease trials: the Tampere recommendations

OBJECTIVE

A gluten-free diet is the only treatment option of coeliac disease, but recently an increasing number of trials have begun to explore alternative treatment strategies. We aimed to review the literature on coeliac disease therapeutic trials and issue recommendations for outcome measures.

DESIGN

Based on a literature review of 10 062 references, we (17 researchers and 2 patient representatives from 10 countries) reviewed the use and suitability of both clinical and non-clinical outcome measures. We then made expert-based recommendations for use of these outcomes in coeliac disease trials and identified areas where research is needed.

RESULTS

We comment on the use of histology, serology, clinical outcome assessment (including patient-reported outcomes), quality of life and immunological tools including gluten immunogenic peptides for trials in coeliac disease.

CONCLUSION

Careful evaluation and reporting of outcome measures will increase transparency and comparability of coeliac disease therapeutic trials, and will benefit patients, healthcare and the pharmaceutical industry.

Elevated serum antiphospholipid antibodies in adults with celiac disease

BACKGROUND AND AIMS

An increased incidence of thrombosis is suggested in celiac disease. We explored serum levels of antiphospholipid antibodies in untreated and treated adult celiac disease patients.

METHODS

A cohort of 179 biopsy-proven celiac disease patients (89 untreated, 90 on long-term gluten-free diet) and 91 non-celiac controls underwent clinical examination, assessment of celiac serology and enzyme immunoassay testing for anticardiolipin IgG and IgM, prothrombin IgG, and phosphatidylserine-prothrombin IgG and IgM.

RESULTS

The level of antiphospholipid antibodies was higher in celiac disease patients compared with controls: anticardiolipin IgG 4.9 (0.7-33.8) vs 2.2 (0.4-9.6) U/ml, antiprothrombin IgG 2.9 (0.3-87.8) vs 2.1 (0.5-187.0) U/ml, antiphosphatidylserine-prothrombin IgG 6.9 (0.0-54.1) vs 2.3 (0.5-15.1) U/ml; p < 0.05 for all. Anticardiolipin IgG, antiprothrombin IgG and antiphosphatidylserine-prothrombin IgG were higher in treated compared with untreated patients. The phenotype of celiac disease at presentation (gastrointestinal symptoms, malabsorption or anemia, and extraintestinal symptoms or screen-detected disease) had no effect on the level of serum antiphospholipid antibodies.

CONCLUSION

The serum level of antiphospholipid antibodies is increased in adults with celiac disease. The higher level of antibodies in treated patients suggests that the increase is not gluten-dependent. The prothrombotic role of antiphospholipid antibodies in celiac disease warrants further studies.

The Effect of Gluten-free Diet on Clinical Symptoms and the Intestinal Mucosa of Patients With Potential Celiac Disease

In this prospective study, we evaluated the effect of gluten-free diet (GFD) in a cohort of 65 children with potential celiac disease. Patients received GFD for signs/symptoms (N = 47) or parents' choice (N = 18). Most frequent signs/symptoms were low body mass index (36%), recurrent abdominal pain (34%), and diarrhea (19%). Of the 35/47 patients followed-up on GFD, only 54% (19/35) showed a complete clinical response. In 9 of 65 patients an intestinal biopsy was also performed after at least 1 year of GFD. No significant differences were observed in terms of Marsh grade (P = 0.33), lamina propria CD25+ cells (P = 0.80), CD3+ (P = 0.9), and γδ+ (P = 0.59) intraepithelial lymphocytes density and intestinal anti-TG2 deposits (P = 0.60). In conclusion, caution is necessary before attributing all symptoms to gluten in this condition.

ROC-king onwards: intraepithelial lymphocyte counts, distribution & role in coeliac disease mucosal interpretation

OBJECTIVES

Counting intraepithelial lymphocytes (IEL) is central to the histological diagnosis of coeliac disease (CD), but no definitive 'normal' IEL range has ever been published. In this multicentre study, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off between normal and CD (Marsh III lesion) duodenal mucosa, based on IEL counts on >400 mucosal biopsy specimens.

DESIGN

The study was designed at the International Meeting on Digestive Pathology, Bucharest 2015. Investigators from 19 centres, eight countries of three continents, recruited 198 patients with Marsh III histology and 203 controls and used one agreed protocol to count IEL/100 enterocytes in well-oriented duodenal biopsies. Demographic and serological data were also collected.

RESULTS

The mean ages of CD and control groups were 45.5 (neonate to 82) and 38.3 (2-88) years. Mean IEL count was 54±18/100 enterocytes in CD and 13±8 in normal controls (p=0.0001). ROC analysis indicated an optimal cut-off point of 25 IEL/100 enterocytes, with 99% sensitivity, 92% specificity and 99.5% area under the curve. Other cut-offs between 20 and 40 IEL were less discriminatory. Additionally, there was a sufficiently high number of biopsies to explore IEL counts across the subclassification of the Marsh III lesion.

CONCLUSION

Our ROC curve analyses demonstrate that for Marsh III lesions, a cut-off of 25 IEL/100 enterocytes optimises discrimination between normal control and CD biopsies. No differences in IEL counts were found between Marsh III a, b and c lesions. There was an indication of a continuously graded dose-response by IEL to environmental (gluten) antigenic influence.

Intraepithelial lymphocyte immunophenotype: a useful tool in the diagnosis of celiac disease

According to new ESPGHAN guidelines, gluten challenge is considered necessary when there is doubt about the initial diagnosis of celiac disease (CD). The main aim of this study was to quantify intraepithelial lymphocyte (IEL) immunophenotype on celiac patients on gluten-containing diet (GCD) compared to those on gluten-free diet (GFD). Another aim was to evaluate the clinical utility of IELs in the CD diagnosis, especially in selected patients on GFD where diagnostic uncertainty remains. IEL immunophenotype (TCRγδ and NK-like IELs) were studied by flow cytometry in 111 children with CD (81 children with CD on GCD and 30 celiac patients on GFD) and a control group (10 children). Duration of GFD was 5.4 ± 1.6 years. TCRγδ IELs in celiac patients receiving a GCD or GFD were significantly higher (p < 0.001) than in the control group. NK-like IELs in patients receiving a GCD or GFD were significantly lower than in the control group (p < 0.001). We observed a permanent decrease of NK-like IELs and an increment of TCRγδ IELs after following an adequate establishment and compliance of a long-term GFD in celiac patients. Recognition of IELs changes in the intestinal mucosa on celiac patients after long-term establishment of a GFD could constitute a useful tool for CD diagnosis in various situations: in which there is doubt about the initial diagnosis and repeat biopsy is necessary (avoiding the need of gluten challenges), and in those patients with symptoms/signs suggestive of CD who maintain a low gluten diet.

Clinical Characteristics and the Dietary Response in Celiac Disease Patients Presenting With or Without Anemia

BACKGROUND AND AIMS

It remains unclear as to what are the clinical characteristics associated with the presence of anemia at celiac disease diagnosis, and how these are affected by a gluten-free diet. We investigated these issues in a prospective study.

METHODS

Clinical and demographic data, small-bowel mucosal histology, serology, and laboratory parameters, body mass index (BMI), and bone mineral density (BMD) both at diagnosis and after 1 year on a gluten-free diet were investigated in 163 adults with celiac disease. Gastrointestinal symptoms and psychological well-being were evaluated by validated Gastrointestinal Symptom Rating Scale and Psychological General Well-Being questionnaires. All study variables were compared between participants with and without anemia at celiac disease diagnosis.

RESULTS

Altogether, 23% of the patients had anemia at diagnosis. Anemic patients were more often women (P=0.001) and had more gastrointestinal symptoms (P=0.004) and were less often screen detected (P=0.009). Further, they had higher celiac antibody values (P=0.007) and a lower total iron (P<0.001), BMI (P=0.003), and density of mucosal γδ+ intraepithelial lymphocytes (P=0.033). After 1 year on a gluten-free diet, the anemia group had a lower mucosal villous height-crypt depth ratio (P=0.008) and BMI (P=0.050), and higher antibody values (P=0.012) and densities of CD3 (P=0.008) and αβ+ intraepithelial lymphocytes (P=0.022). There was no significant difference between the groups in their bone mineral density, Gastrointestinal Symptom Rating Scale and Psychological General Well-Being.

CONCLUSIONS

Celiac patients with anemia had more severe disease than nonanemic patients in terms of the serology and a lower BMI. Further, they evinced a slower histologic response to the dietary treatment. An early diagnosis and careful follow-up are important in these patients.

The Decreasing Prevalence of Severe Villous Atrophy in Dermatitis Herpetiformis: A 45-Year Experience in 393 Patients

GOALS

We analyzed from our prospectively collected series of patients with dermatitis herpetiformis (DH) whether small-bowel histologic findings are changing and how serum tissue transglutaminase (TG2) IgA antibodies correlate to mucosal damage.

BACKGROUND

DH is an extraintestinal manifestation of celiac disease presenting with itchy blistering rash and pathognomonic IgA deposits in the skin. Prominent gastrointestinal symptoms are rare, and small-bowel findings range from severe villous atrophy (SVA) and partial villous atrophy (PVA) to normal mucosa with inflammatory changes.

METHODS

The cohort included 393 patients (214 male and 179 female) with DH having small-bowel biopsies performed at Tampere University Hospital since 1970. The small-bowel findings were calculated in the three 15-year periods, and in the last period they were correlated with serum IgA class TG2 antibody levels measured by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of SVA decreased significantly (P=0.032), from 42% in the first study period to 29% in the last study period. A concomitant increase was seen in PVA, from 33% to 41%, and normal villous architecture, from 25% to 30%. The patients with SVA (P<0.001) and PVA (P=0.046) had significantly higher TG2 antibody levels than those with normal villous architecture.

CONCLUSIONS

This long-term study in patients with DH disclosed a significant decrease in the occurrence of SVA. Serum IgA TG2 antibody levels correlated to damage in the small bowel. The trend toward milder small-bowel histology in DH suggests that a similar pattern could occur in the pool of undiagnosed celiac disease from which DH develops.

The composition of T cell subtypes in duodenal biopsies are altered in coeliac disease patients

One of the hallmarks of Celiac disease (CD) is intraepithelial lymphocytosis in the small intestine. Until now, investigations to characterize the T cell subpopulations within the epithelial layer have not discriminated between the heterodimeric co-receptor molecule, CD8αβ, and the possibly immunoregulatory CD8αα homodimer molecule. Besides TCRαβ+ CD4+ cells, no other phenotypes have been shown to be gluten-reactive. Using flow cytometry on lymphocytes from duodenal biopsies, we determined that the number of B cells (CD3- CD19+) and the number of CD3+ CD4- CD8- double-negative (DN) T cells were elevated 6–7 fold in children with CD. We next isolated and quantified intraepithelial lymphocytes (IELs) from biopsies obtained from patients (both children and adults) with CD, potential CD and non-CD controls. Flow cytometric analysis of the duodenal T cell subpopulations was performed including the markers TCRαβ, TCRγδ, CD4, CD8α and CD8β. Proportions of γδ T cells and CD8αβ⁺ cells among IELs were increased in CD patients, whereas proportions of CD4+ CD8αα+ and CD4+ single-positive T cells were decreased. Additionally, two gluten-reactive T cell lines (TCLs) derived from CD biopsies were analyzed for changes in proportions of T cell subsets before and after gluten stimulation. In a proliferation assay, dividing cells were tracked with carboxyfluorescein succinimidyl ester (CFSE), and both αβ and γδ T cells proliferated in response to gluten. Changes in duodenal T cell subpopulations in potential CD patients followed the same pattern as for CD patients, but with less pronounced effect.

Dermatitis herpetiformis: a cutaneous manifestation of coeliac disease

Dermatitis herpetiformis (DH) is an itchy blistering skin disease with predilection sites on elbows, knees, and buttocks. Diagnosis is confirmed by showing granular immunoglobulin A deposits in perilesional skin. DH is one manifestation of coeliac disease; the skin symptoms heal with gluten free diet (GFD) and relapse on gluten challenge. Of the first-degree relatives, 5% may be affected by either condition. Tissue transglutaminase (TG2) is the autoantigen in coeliac disease and epidermal transglutaminase (TG3) in DH. Both diseases conditions exhibit TG2-specific autoantibodies in serum and small bowel mucosa; patients with DH have IgA-TG3 in the skin. There are some divergencies between these two phenotypes. One-fourth of DH patients do not have small bowel mucosal villous atrophy, but virtually all have coeliac-type inflammatory changes. The skin symptoms respond slowly to GFD. The incidence of coeliac disease is increasing, whereas the opposite is true for DH. A female predominance is evident in coeliac disease, while DH may be more common in males. Coeliac disease carries the risk of small intestinal T-cell lymphoma; in DH B-cell lymphomas at any site may prevail. Adult coeliac disease carries a slightly increased elevated mortality risk, whereas in DH, the relative mortality rate is significantly decreased. Key messages Dermatitis herpetiformis is a cutaneous manifestation of coeliac disease; both conditions are genetically determined and gluten-dependent. Gastrointestinal symptoms and the degree of villous atrophy are less obvious in dermatitis herpetiformis than in coeliac disease. Both show tissue transglutaminase (TG2) specific autoantibodies in serum and small bowel mucosa. In addition, TG3-targeted IgA antibodies are found in the skin of DH patients Both conditions carry an increased elevated risk of lymphoma, in coeliac disease small intestinal T-cell lymphoma, in dermatitis herpetiformis mainly B-cell lymphoma at various sites. Coeliac disease is currently eight times more common that DH; the incidence of DH is decreasing in contrast to that of coeliac disease, where it is increasing.

Small bowel villous atrophy: celiac disease and beyond

Small bowel villous atrophy can represent a diagnostic challenge for gastroenterologists and pathologists. In Western countries small bowel atrophy and mild non-atrophic alterations are frequently caused by celiac disease. However, other pathology can mimic celiac disease microscopically, widening the differential diagnosis. The several novelties on this topic and the introduction of the device-assisted enteroscopy in the diagnostic flowchart make an update of the literature necessary. Areas covered: In this review, a description of the different clinical scenarios when facing with small bowel mucosal damage, particularly small bowel atrophy, is described. The published literature on this subject has been summarized and reviewed. Expert commentary: When an intestinal mucosal alteration is histologically demonstrated, the pathology report forms part of a more complex workup including serological data, clinical presentation and clinical history. A multidisciplinary team, including pathologists and enteroscopy-devoted endoscopists, is frequently required to manage patients with small bowel alterations, especially in cases of severe malabsorption syndrome.

Intraepithelial lymphocytes, scores, mimickers and challenges in diagnosing gluten-sensitive enteropathy (celiac disease)

The upper digestive tract is routinely scoped for several causes of malabsorption, and the number of duodenal biopsy specimens has increased notably in the last 10 years. Gluten-sensitive enteropathy (GSE) is an autoimmune disease, which shows an increasing prevalence worldwide and requires a joint clinico-pathological approach. The classical histopathology of GSE with partial or total villous blunting is well recognized, but the classification of GSE is not straightforward. Moreover, several mimickers of GSE with intraepithelial lymphocytosis have been identified in the last 20 years, with drug interactions and medical comorbidities adding to the conundrum. In this review, we report on the normal duodenal mucosa, the clinical presentation and laboratory diagnosis of GSE, the duodenal intraepithelial lymphocytes and immunophenotype of GSE-associated lymphocytes, the GSE mimickers, the differences "across oceans" among guidelines in diagnosing GSE, and the use of a synoptic report for reporting duodenal biopsies in both children and adults in the 21st century.

Anemia and Iron Deficiency in Children With Potential Celiac Disease

OBJECTIVES

Active screening for celiac disease frequently detects seropositive children with normal villous morphology (potential celiac disease). It remains unclear whether these subjects should be treated. We here investigated the prevalence of anemia and iron deficiency in children with potential and mucosal atrophy celiac disease.

METHODS

The prospective study involved 19 children with potential disease, 67 with partial or subtotal villous atrophy (P/SVA), and 16 with total villous atrophy (TVA). Twenty-three healthy children comprised the control group. The groups were compared for various clinical, histological, and laboratory parameters and hepcidin.

RESULTS

The prevalence of abnormal parameters was as follows (controls, potential celiac disease, P/SVA, and TVA, respectively): anemia 0%, 15%, 22%, and 63%; low iron 5%, 0%, 14%, and 50%; increased transferrin receptor 1 5%, 16%, 20%, and 47%; low ferritin 0%, 21%, 35%, and 87%; and low transferrin saturation 10%, 11%, 41%, and 71%. One subject had low folate and none had low vitamin B12. The median values for hemoglobin, total iron, ferritin, and transferrin saturation were significantly lower and transferrin receptor 1 values higher in TVA group compared with other groups. After a median of 7 months on a gluten-free diet hemoglobin, total iron, ferritin, and albumin in children with P/SVA exceeded the baseline values in the potential celiac disease group.

CONCLUSIONS

The development of anemia and iron deficiency in celiac disease is a continuum and may already be present in children with normal villous morphology, advocating an early diagnosis and possible dietary treatment of these patients.

Flow cytometry of duodenal intraepithelial lymphocytes improves diagnosis of celiac disease in difficult cases

BACKGROUND

Diagnosis of celiac disease is difficult when the combined results of serology and histology are inconclusive. Studies using flow cytometry of intraepithelial lymphocytes (IELs) have found that celiac patients have increased numbers of γδ IELs, along with a decrease in CD3-CD103 + IELs.

OBJECTIVE

The objective of this article is to assess the role of flow cytometric analysis of IELs in the diagnosis of celiac disease in difficult cases.

METHODS

A total of 312 patients with suspicion of celiac disease were included in the study. Duodenal biopsy samples were used for histological assessment and for flow cytometric analysis of IELs.

RESULTS

In 46 out of 312 cases (14.7%) the combination of serology and histology did not allow the confirmation or exclusion of celiac disease. HLA typing had been performed in 42 of these difficult cases. Taking into account HLA typing and the response to a gluten-free diet, celiac disease was excluded in 30 of these cases and confirmed in the remaining 12. Flow cytometric analysis of IELs allowed a correct diagnosis in 39 out of 42 difficult cases (92.8%) and had a sensitivity of 91.7% (95% CI: 61.5% to 99.8%) and a specificity of 93.3% (95% CI: 77.9% to 99.2%) for the diagnosis of celiac disease in this setting.

CONCLUSION

Flow cytometric analysis of IELs is useful for the diagnosis of celiac disease in difficult cases.

Intraepithelial lymphocytes subsets in different forms of celiac disease

AIM

The enumeration of intraepithelial lymphocytes subsets (total, γδ, and CD3(-) IELs) by flow cytometry (FCM), named as IEL lymphogram, constitutes a useful tool for celiac disease (CD) diagnosis. The aim of this study was to quantify IELs by FCM and their diagnostic value to differentiate active, silent and potential CD.

METHODS

Prospective study of 60 active and 20 silent CD patients, and 161 controls in which duodenal biopsy and IEL quantification by FCM was performed.

RESULTS

Active and silent CD patients had significant higher levels of both total and γδ IELs than absent CD patients (P < 0.0001 and P < 0.0001, P = 0.012 and P < 0.011; respectively). Active and silent CD patients had significant lower levels of CD3(-) IELs than absent CD patients (P < 0.047 and P < 0.009, respectively). Moreover, they were lower in silent than in active CD patients (P = 0.002). Changes of IELs subsets were more marked in children than adults active CD. The optimal IEL lymphogram cut off values for active CD diagnosis were: ≥10, ≥15 and ≤9 %, and with better performance characteristics for silent CD: ≥ 11, ≥10 and ≤5 %.

CONCLUSION

The evaluation of IELs subsets by FCM is useful to confirm diagnosis of active and silent CD.

Novel diagnostic techniques for celiac disease

The diagnosis of celiac disease has long been based on the demonstration of gluten-induced small-bowel mucosal damage. However, due to the constantly increasing disease prevalence and limitations in the histology-based criteria there is a pressure towards more serology-based diagnostics. The serological tools are being improved and new non-invasive methods are being developed, but the constantly refined endoscopic and histologic techniques may still prove helpful. Moreover, growing understanding of the disease pathogenesis has led researchers to suggest completely novel approaches to celiac disease diagnostics regardless of disease activity. In this review, we will elucidate the most recent development and possible future innovations in the diagnostic techniques for celiac disease.

Serum transglutaminase 3 antibodies correlate with age at celiac disease diagnosis

BACKGROUND

Transglutaminase (TG)2 is the autoantigen in celiac disease, but also TG3 antibodies have been detected in the serum of celiac disease patients.

AIMS

To investigate the correlations between serum TG3 antibodies and clinical and histological manifestations of celiac disease and to assess gluten-dependency of TG3 antibodies.

METHODS

Correlations between serum TG3 antibody levels measured from 119 adults and children with untreated coeliac disease and the demographic data, clinical symptoms, celiac antibodies, histological data and results of laboratory tests and bone mineral densities were tested. TG3 antibodies were reinvestigated in 97 celiac disease patients after 12 months on a gluten-free diet (GFD).

RESULTS

TG3 antibody titers were shown to correlate with the age at celiac disease diagnosis. Further, negative correlation with TG3 antibodies and intestinal γδ+ cells at diagnosis and on GFD was detected. Correlations were not detected with the clinical manifestation of celiac disease, TG2 or endomysial autoantibodies, laboratory values, severity of mucosal villous atrophy, associated diseases or complications. TG3 antibody titers decreased on GFD in 56% of the TG3 antibody positive patients.

CONCLUSION

Serum TG3 antibody positivity in celiac disease increases as the diagnostic age rises. TG3 antibodies did not show similar gluten-dependency as TG2 antibodies.

A Prospective Study on the Usefulness of Duodenal Bulb Biopsies in Celiac Disease Diagnosis in Children: Urging Caution

OBJECTIVES

Several recent celiac disease guidelines recommend the acquisition of duodenal bulb biopsies for diagnostics. This is in conflict with previously reported evidence and routine practice from the 1960s onward. We reopened the issue in a prospective multicenter study and used morphometric variables in evaluating the usefulness of bulb biopsies in children. We further sought to establish whether deposits of IgA targeting bulb transglutaminase 2 (TG2) could be of diagnostic help.

METHODS

Diagnoses of celiac disease were based on clinic and distal duodenal histopathology statements. Centralized reading of villous height (VH) to crypt depth (CrD) ratios and IgA deposits was performed on anatomical duodenal bulb specimens. All children participating also underwent routine investigations for other diseases.

RESULTS

Twenty-two children had celiac disease, and another 22 served as non-celiac disease controls. The quality of the anatomical bulb specimens was unsatisfactory for reliable morphometric measurements in 20 out of 44 (45%) patients even after recuttings. All celiac disease patients had VH:CrD<2.0 (mean 0.2) but also 10 out of 13 (77%) non-celiac control patients had an injured bulb mucosal lining (mean 1.3) even up to false-positive "flat lesion". Bulb IgA deposits were able to separate celiac disease from disease controls.

CONCLUSIONS

Morphological injury is common in the anatomical bulb even without celiac disease, increasing the risk of false-positive diagnoses. Premature conclusions might have been drawn on current care guidelines as to celiac disease diagnosis based solely on anatomical bulb specimens. Bulb mucosal IgA targeting TG2 in poor quality biopsy specimens is a powerful clinical tool in finding celiac disease patients.

Quantitative peripheral blood perturbations of γδ T cells in human disease and their clinical implications

Human γδ T cells, which play innate and adaptive, protective as well as destructive, roles in the immune response, were discovered in 1986, but the clinical significance of alterations of the levels of these cells in the peripheral blood in human diseases has not been comprehensively reviewed. Here, we review patterns of easily measurable changes of this subset of T cells in peripheral blood from relevant publications in PubMed and their correlations with specific disease categories, specific diagnoses within disease categories, and prognostic outcomes. These collective data suggest that enumeration of γδ T cells and their subsets in the peripheral blood of patients could be a useful tool to evaluate diagnosis and prognosis in the clinical setting.

Predictors and Significance of Incomplete Mucosal Recovery in Celiac Disease After 1 Year on a Gluten-Free Diet

OBJECTIVES

In celiac disease, a follow-up biopsy taken 1 year after diagnosis is considered important in monitoring histological recovery. In many cases, recovery is incomplete, and the clinical significance of this is poorly understood. We now investigated associated factors and the significance of imperfect histological recovery in patients in whom the follow-up had been completed.

METHODS

Two hundred sixty-three biopsy-proven patients were divided into two groups: histological recovery and incomplete recovery after 1 year on gluten-free diet. Serology, laboratory values, bone mineral density, and different clinical variables were measured at diagnosis and after 1 year. Gastrointestinal symptoms and quality of life were assessed by validated questionnaires. Further, long-term follow-up data on mortality, malignancies, and other severe complications were collected.

RESULTS

The incomplete recovery group had more severe mucosal damage (P=0.003), higher antibody values (P=0.017), and more signs of malabsorption (P<0.001) at diagnosis. There was no difference in gender, symptoms or quality of life, family history of celiac disease, or comorbidities. At follow-up, there was still a difference in antibodies (P=0.018) and femoral T-scores (P=0.024). Histologically recovered patients showed better dietary adherence, although it was excellent in both groups (97% vs. 87%, P<0.001). There was no difference in long-term outcomes between groups.

CONCLUSIONS

The presence of more severe disease in terms of histology, serology, and signs of malabsorption was associated with histological non-response. In patients with high dietary adherence, incomplete villous recovery after 1 year does not affect the clinical response or long-term prognosis. A personalized approach is required to decide the optimal timing of the follow-up biopsy.

Celiac disease evolving into dermatitis herpetiformis in patients adhering to normal or gluten-free diet

OBJECTIVE

Dermatitis herpetiformis (DH) is a cutaneous form of celiac disease affecting ∼ 17% of celiac disease patients. The aim was to determine how often celiac disease precedes the development of DH, and what is the impact of gluten-free diet (GFD) in this phenotype change.

MATERIAL AND METHODS

Our prospectively collected DH series from 1970 comprised 514 patients. We analyzed all DH patients who at least 2 years earlier had been diagnosed with celiac disease. DH diagnosis was confirmed by showing immunoglobulin A deposits in dermis. Serological and small bowel mucosal findings were analyzed, and the strictness of GFD treatment before and after the diagnosis of DH was evaluated.

RESULTS

Twenty (4%) DH patients had a prior diagnosis of celiac disease. The median time interval between celiac disease and DH detection was 9.5 years. Before DH appeared 4 patients had been on a normal gluten-containing diet, 10 had dietary lapses on a GFD, and 6 were on a strict GFD. Celiac autoantibodies were positive in 7 out of 19 patients, and 5 out of 7 undergoing small bowel biopsy had partial villous atrophy. Following DH diagnosis the rash was controlled after a median of 6 months on a strict GFD.

CONCLUSIONS

Patients with celiac disease may develop DH by time. This is most often an indicator of poor adherence to GFD, and a rigorous dietary intervention is necessary. In the majority of cases, DH will be detected without prior celiac disease diagnosis, but the physicians should recognize this phenotype alteration.

Development of drugs for celiac disease: review of endpoints for Phase 2 and 3 trials

Celiac disease is a lifelong disorder for which there is currently only one known, effective treatment: a gluten-free diet. New treatment approaches have recently emerged; several drugs are in Phase 2 trials and results appear promising; however, discussion around regulatory endpoints is in its infancy. We will briefly discuss the drugs that are under development and then shift our attention to potential trial endpoints, such as patient-reported outcomes, histology, serology, gene expression analysis and other tests. We will outline the differing requirements for proof-of-concept Phase 2 trials and Phase 3 registration trials, with a particular emphasis on current thinking in regulatory agencies. We conclude our paper with recommendations and a glossary of regulatory terms, to enable readers who are less familiar with regulatory language to take maximum advantage of this review.