Intraepithelial gamma delta T-cell-receptor lymphocytes and genetic susceptibility to coeliac disease

Intraepithelial Lymphogram in the Diagnosis of Celiac Disease in Adult Patients: A Validation Cohort

BACKGROUND

Celiac disease is a gluten-related pathology, highly prevalent and heterogeneous in its clinical presentation, which leads to delays in diagnosis and misdiagnosis. The analysis of duodenal intraepithelial lymphocytes (IELs) by flow cytometry (lymphogram) is emerging as a discriminative tool in the diagnosis of various forms of celiac disease (CD).

AIMS

The aim of this study was to validate IEL lymphogram performance in the largest adult series to our knowledge, in support of its use as a diagnostic tool and as a biomarker of the dynamic celiac process.

METHODS

This was a retrospective study including 768 adult patients (217 with active CD, 195 on a gluten-free diet, 15 potential CD patients, and 411 non-celiac controls). The IEL subset cut-off values were established to calculate the diagnostic accuracy of the lymphogram.

RESULTS

A complete celiac lymphogram profile (≥14% increase in T cell receptor [TCR]γδ IELs and simultaneous ≤4% decrease in surface-negative CD3 [sCD3-] IELs) was strongly associated with active and potential forms in over 80% of the confirmed patients with CD, whereas the remaining patients with CD had partial lymphogram profiles (≥14% increase in TCRγδ or ≤4% decrease in sCD3- IELs), with lower diagnostic certainty. None of these patients had a non-celiac lymphogram. Quantifying the TCRγδ versus sCD3- imbalance as a ratio (≥5) is a discriminative index to discard or suspect CD at diagnosis.

CONCLUSIONS

We have validated the IEL lymphogram's diagnostic efficiency (79% sensitivity, 98% specificity), with an LR+ accuracy of 36.2. As expected, the increase in TCRγδ IELs is a reliable marker for celiac enteropathy, while changes in sCD3- IEL levels throughout the dynamic CD process are useful biomarkers of mucosal lesions.

Clinical, Diagnostic and Prognostic Characteristics of Primary Cutaneous Gamma Delta T-cell Lymphomas

Primary cutaneous γδ T-cell lymphoma (PCGDTL) is a rare subtype of non-Hodgkin lymphoma (NHL) that arises from T-cells with γδ T-cell receptors. The exact incidence of PCGDTL is unknown, as it is usually lumped with other cutaneous lymphomas, which are also uncommon. It is one of the peripheral T-cell lymphoma (PTCL) subtypes which is known to have a dismal prognosis due to poor response and the paucity of available therapies. Despite the rarity and uncertainties of PCGDTL, a number of studies over the past decade were published about the pathologic, diagnostic, cytogenetic and clinical features of this disease. These diagnostic advances will open the doors to explore new therapeutics for this rare entity, specifically targeted and immune therapies. In this review, we highlight these advances, summarize the contemporary treatment approaches, and shed the light on future potential therapeutic targets.

Assessment of Duodenal Intraepithelial Lymphocyte Composition (Lymphogram) for Accurate and Prompt Diagnosis of Celiac Disease in Pediatric Patients

INTRODUCTION

Quantitative and phenotypic analyses of duodenal intraepithelial lymphocytes (IELs) by flow cytometry (IEL lymphogram) confer specificity and enable the diagnosis even in unconventional presentations of celiac disease (CD). To evaluate the validity of the IEL lymphograms in the pediatric population for new insights into their use as biomarkers in the natural history of CD.

METHODS

We retrospectively included 1,211 children (602 with active CD, 92 on a gluten-free diet, 47 with potential CD, and 470 nonceliac controls) who required duodenal biopsies in this study. The cutoff values for IEL subsets were established to calculate the probability of disease according to the lymphogram.

RESULTS

A celiac lymphogram (a ≥15% increase in gamma-delta T-cell receptor IELs and a simultaneous ≤6% decrease in CD3 surface-negative [sCD3-]) IELs was strongly associated with the diagnosis of active CD, which was present in 89.7% of the confirmed patients. The remaining 10% of the celiac patients had a partial celiac lymphogram (≥15% increase gamma-delta T-cell receptor IELs or ≤6% decrease in sCD3- IELs), with lower diagnostic certainty. On a gluten-free diet, nearly 20% of the patients were indistinguishable from nonceliac subjects based on the lymphogram. In potential CD, a decrease in sCD3- IELs was a risk marker of progression to villous atrophy and a diagnosis of active CD.

DISCUSSION

If a biopsy is clinically indicated, the IEL lymphogram adds specificity to the histological findings, reducing diagnostic delays and misdiagnoses. The lymphogram is useful for monitoring the natural progression of the disease and predicting the transition from potential celiac to overt CD.

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.

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.

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.

Gluten-Induced Extra-Intestinal Manifestations in Potential Celiac Disease-Celiac Trait

Celiac disease patients may suffer from a number of extra-intestinal diseases related to long-term gluten ingestion. The diagnosis of celiac disease is based on the presence of a manifest small intestinal mucosal lesion. Individuals with a normal biopsy but an increased risk of developing celiac disease are referred to as potential celiac disease patients. However, these patients are not treated. This review highlights that patients with normal biopsies may suffer from the same extra-intestinal gluten-induced complications before the disease manifests at the intestinal level. We discuss diagnostic markers revealing true potential celiac disease. The evidence-based medical literature shows that these potential patients, who are “excluded” for celiac disease would in fact benefit from gluten-free diets. The question is why wait for an end-stage disease to occur when it can be prevented? We utilize research on dermatitis herpetiformis, which is a model disease in which a gluten-induced entity erupts in the skin irrespective of the state of the small intestinal mucosal morphology. Furthermore, gluten ataxia can be categorized as its own entity. The other extra-intestinal manifestations occurring in celiac disease are also found at the latent disease stage. Consequently, patients with celiac traits should be identified and treated.

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.

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.

Intestinal Production of Anti-Tissue Transglutaminase 2 Antibodies in Patients with Diagnosis Other Than Celiac Disease

It has been hypothesized that gluten-dependent production of anti-tissue-transglutaminase 2 (anti-TG2) antibodies may occur only at an intestinal level. We have investigated intestinal production of anti-TG2 antibodies in 136 patients with normal serum levels of anti-TG2 antibodies and normal duodenal mucosa. Intestinal deposits of anti-TG2 antibodies were evaluated by immunofluorescence and anti-TG2 antibodies released in organ culture supernatants measured by ELISA. Intestinal antibody libraries were obtained from 10 subjects. Immunohistochemistry for CD25⁺, CD3⁺, and TCR-γδ⁺ was assessed in subjects with positive (n = 32) and negative (n = 31) intestinal anti-TG2 antibodies. Globally 33/136 (24%) seronegative patients produced anti-TG2 autoantibodies at an intestinal level. Antibody libraries analysis confirmed the anti-TG2 antibodies mucosal production in all (n = 8) positive subjects. Lamina propria CD25⁺ cell count was significantly (p < 0.05) higher in patients with intestinal anti-TG2. Moreover, 13/32 (41%) of them showed high TCR-γδ⁺/CD3⁺ ratios. Intestinal anti-TG2 antibody production does not show absolute specificity for CD. It is seen more often in association with inflamed mucosa. Further investigations are necessary to prove the possible role of dietary gluten.

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.

Distal duodenum versus duodenal bulb: intraepithelial lymphocytes have something to say in celiac disease diagnosis

BACKGROUND AND AIM

After clinical screening and the serological test, many patients still require a duodenal biopsy for celiac disease diagnosis. Mild histological lesions, unspecific findings and patchiness are frequent outcomes of this mandatory diagnostic tool, thus complicating clinical decisions.

METHODS

We analyzed the lymphoid components [number of total intraepithelial lymphocytes (IELs), TcR-γδ and CD3(-)IELs] of the duodenal epithelium by flow cytometry in samples obtained from bulb and distal duodenum during upper gastrointestinal endoscopies performed for diagnostic purposes.

RESULTS

IEL counts and IEL subset distribution (IEL lymphogram) remain invariant along duodenal mucosa revealing a specific profile (immunophenotype) that characterizes either a healthy mucosa or a celiac mucosa. The celiac immunophenotype persists regardless of the biopsy's anatomical location or the corresponding histological findings.

CONCLUSIONS

We propose the IEL lymphogram by flow cytometry as an immunological parameter to discern celiac condition from healthy mucosa. This obviates not only misinterpretation of minor histological changes, but also patchiness and the concerns about the location and number of biopsies.

Glutenase ALV003 attenuates gluten-induced mucosal injury in patients with celiac disease

BACKGROUND & AIMS

Gluten ingestion leads to small intestinal mucosal injury in patients with celiac disease, necessitating strict life-long exclusion of dietary gluten. Despite adherence to a gluten-free diet, many patients remain symptomatic and still have small intestinal inflammation. In this case, nondietary therapies are needed. We investigated the ability of ALV003, a mixture of 2 recombinant gluten-specific proteases given orally, to protect patients with celiac disease from gluten-induced mucosal injury in a phase 2 trial.

METHODS

We established the optimal daily dose of gluten to be used in a 6-week challenge study. Then, in the intervention study, adults with biopsy-proven celiac disease were randomly assigned to groups given ALV003 (n = 20) or placebo (n = 21) together with the daily gluten challenge. Duodenal biopsies were collected at baseline and after gluten challenge. The ratio of villus height to crypt depth and densities of intraepithelial lymphocytes were the primary end points.

RESULTS

A daily dose of 2 g gluten was selected for the intervention study. Sixteen patients given ALV003 and 18 given placebo were eligible for efficacy evaluation. Biopsies from subjects in the placebo group showed evidence of mucosal injury after gluten challenge (mean villus height to crypt depth ratio changed from 2.8 before challenge to 2.0 afterward; P = .0007; density of CD3(+) intraepithelial lymphocytes changed from 61 to 91 cells/mm after challenge; P = .0003). However, no significant mucosal deterioration was observed in biopsies from the ALV003 group. Between groups, morphologic changes and CD3(+) intraepithelial lymphocyte counts differed significantly from baseline to week 6 (P = .0133 and P = .0123, respectively). There were no statistically significant differences in symptoms between groups.

CONCLUSIONS

Based on a phase 2 trial, the glutenase ALV003 appears to attenuate gluten-induced small intestinal mucosal injury in patients with celiac disease in the context of an everyday gluten-free diet containing daily up to 2 g gluten. Clinicaltrial.gov,

NUMBERS

NCT00959114 and NCT01255696.

Anti-TCR gamma antibody in celiac disease: the value of count on formalin-fixed paraffin-embedded biopsies

Small bowel intraepithelial lymphocytosis (IL) may depend from different causes, including celiac disease (CD). Demonstration of increased number of duodenal T cell receptor gamma-delta (TCRγδ) positive intraepithelial lymphocytes (IELs) has been used to support CD diagnosis on frozen material. This work evaluates a new commercially available anti-TCRγ antibody on formalin-fixed paraffin embedded (FFPE) small bowel biopsies. Anti-CD3 and anti-TCR CγM1 (clone γ3.20) from Thermo Scientific were applied by immunohistochemistry on 59 FFPE biopsies from 18 cases of CD with mild/severe atrophy, 19 cases of IL in CD patients on gluten-free diet (IL-GFD), 14 cases of IL (6/14 with positive CD-related serology), and 8 controls (CTR) with mild duodenitis and negative CD serology and genotyping. IELs/100 epithelial cells were counted in at least six high power fields. CD3+ and TCRγ+ IELs were significantly higher in CD, IL-GFD, and IL compared with CTR, but in contrast to CD3+ IELs, TCRγ+ IELs were significantly increased in CD and IL-GFD compared with IL. Furthermore, TCRγ+ IELs discriminated between IL with negative and positive CD-related serology (p = 0.02). TCRγ+ IELs can be identified on FFPE samples and their evaluation adds useful information for the work-up of small bowel biopsies in CD diagnosis. In fact, TCRγ staining coupled with CD3, may represent an additional tool to recognize cases of latent/potential CD when serology and clinical data are not conclusive or when the histological diagnosis remains equivocal.

Intraepithelial lymphocytes in celiac disease immunopathology

Celiac disease is a T cell-mediated immune disorder induced by dietary gluten that is characterized by the development of an inflammatory anti-gluten CD4 T cell response, anti-gluten antibodies, and autoantibodies against tissue transglutaminase 2 and the activation of intraepithelial lymphocytes (IELs) leading to the destruction of the intestinal epithelium. Intraepithelial lymphocytes represent a heterogeneous population of T cells composed mainly of cytotoxic CD8 T cells residing within the epithelial layer, whose main role is to maintain the integrity of the epithelium by eliminating infected cells and promoting epithelial repair. Dysregulated activation of IELs is a hallmark of CD and is critically involved in epithelial cell destruction and the subsequent development of villous atrophy. In this review, we compare and contrast the phenotype and function of human and mouse small intestinal IELs under physiological conditions. Furthermore, we discuss how conditions of epithelial distress associated with overexpression of IL-15 and non-classical MHC class I molecules induce cytotoxic IELs to become licensed killer cells that upregulate activating NKG2D and CD94/NKG2C natural killer receptors, acquiring lymphokine killer activity. Pathways leading to dysregulated IEL activation could eventually be targeted to prevent villous atrophy and treat patients who respond poorly to gluten-free diet.

Up-regulation of small intestinal interleukin-17 immunity in untreated coeliac disease but not in potential coeliac disease or in type 1 diabetes

Up-regulation of interleukin (IL)-17 in small intestinal mucosa has been reported in coeliac disease (CD) and in peripheral blood in type 1 diabetes (T1D). We explored mucosal IL-17 immunity in different stages of CD, including transglutaminase antibody (TGA)-positive children with potential CD, children with untreated and gluten-free diet-treated CD and in children with T1D. Immunohistochemistry was used for identification of IL-17 and forkhead box protein 3 (FoxP3)-positive cells and quantitative polymerase chain reaction (qPCR) for IL-17, FoxP3, retinoic acid-related orphan receptor (ROR)c and interferon (IFN)-γ transcripts. IL-1β, IL-6 and IL-17 were studied in supernatants from biopsy cultures. Expression of the apoptotic markers BAX and bcl-2 was evaluated in IL-17-stimulated CaCo-2 cells. The mucosal expression of IL-17 and FoxP3 transcripts were elevated in individuals with untreated CD when compared with the TGA-negative reference children, children with potential CD or gluten-free diet-treated children with CD (P < 0·005 for all IL-17 comparisons and P < 0·01 for all FoxP3 comparisons). The numbers of IL-17-positive cells were higher in lamina propria in children with CD than in children with T1D (P < 0·05). In biopsy specimens from patients with untreated CD, enhanced spontaneous secretion of IL-1β, IL-6 and IL-17 was seen. Activation of anti-apoptotic bcl-2 in IL-17-treated CaCo-2 epithelial cells suggests that IL-17 might be involved in mucosal protection. Up-regulation of IL-17 could, however, serve as a biomarker for the development of villous atrophy and active CD.

Dynamics of non-conventional intraepithelial lymphocytes-NK, NKT, and γδ T-in celiac disease: relationship with age, diet, and histopathology

BACKGROUND

Intraepithelial lymphocytes (IEL) are a heterogeneous population of lymphocytes raised in celiac disease (CD), whose role in CD pathogenesis remains to be defined.

AIMS

To investigate how the age of diagnosis, diet, and the severity of the histological lesions are related to the changes observed in unconventional IEL populations.

METHODS

Prospective analysis of 101 confirmed celiac patients from a single center, including 66 at diagnosis (45 children, 21 adults) and 112 non-celiac controls (12 children, 100 adults). IEL from duodenal biopsies were studied by six-color flow cytometry. The results were analyzed in relationship with age, diet (gluten intake), and histopathology (Marsh type).

RESULTS

In comparison with respective age controls, both children and adult patients showed duodenal intraepithelial lymphocytosis with significant differences in every single non-conventional IEL population: CD3+ TCR γδ, NK (CD3-, CD16+, CD56+), NKT (CD3+, CD161+, CD56+), and iNKT (CD3+ Vα24) (P < 0.001 for all). Gluten intake was not only directly associated with severe atrophy, but also with decreased percentages of NK (P = 0.02), NKT (P = 0.003), and iNKT (P = 0.03). Changes in iNKT and γδ IEL were more marked in celiac children compared with celiac adults (P = 0.02 and 0.01, respectively). In contrast, increased CD3+ TCR γδ were diet- and Marsh grade-independent.

CONCLUSIONS

The typical phenotypical profile of intraepithelial lymphocytosis in untreated pediatric and adult celiacs consists of increased CD3+ TCR γδ populations with decreased NK, NKT, and iNKT cells. NK, NKT, and iNKT IEL, but not γδ IEL, are dynamic populations associated with diet, age, and histopathology.

Potential selective advantage mechanism for polymorphic genetics in celiac disease

Celiac Disease is a common cause of morbidity in the developed world but its etiology is still unknown. Considering that Celiac Disease was first documented in Scandinavian Europe, a population exposed to a high fat diet, perhaps the polymorphic genetics of the disease provides balanced polymorphism against this environmental stimulus. Celiac Disease has been associated with higher levels of the T cell receptor (TCR)γδ, receptors that have played a greater role in recognizing microbial lipids. Furthermore, obesity has been associated with lower levels of CD-3 expression while Celiac Disease has been associated with an up regulation of this molecule. These finding might help to describe a balance polymorphism that exists in Celiac Disease as well as an etiological factor that lead to the development of the disease.

Flow cytometry of intestinal intraepithelial lymphocytes in celiac disease

This article reviews the multiple uses of flow cytometry in the diagnosis, monitoring and research of celiac disease, the most prevalent chronic autoimmune gastrointestinal disease. The phenotyping of intraepithelial lymphocytes (IELs) is of clinical relevance in the diagnosis of the disease given the characteristic features of elevated CD3+ IELs (αβ and γδ TcR) and the decrease in CD3- IELs. IEL biomarkers are also useful in the assessment of the response to the gluten-free diet and, importantly, in the diagnosis of the severe complications of celiac disease: refractory celiac disease and enteropathy-associated T-cell lymphoma. Novel applications of flow cytometry for the detection of anti-transglutaminase antibodies (a validated biomarker of celiac disease) and of gluten (the triggering antigen of the autoimmune process) are also discussed. The assessment of diagnostic and prognostic biomarkers by flow cytometry in celiac disease is performed routinely in a growing number of centers and it is an example of the versatility of this technique and its applicability to the research and clinical study of solid tissues.

Serological responses to microbial antigens in celiac disease patients during a gluten-free diet

BACKGROUND

Immunoglobulin A (IgA) autoantibodies to tissue transglutaminase (tTG) are commonly used for screening and diagnosing of celiac disease (CD). Seroreactivity for anti-Saccharomyces cerevisiae antibody (ASCA) and bacterial antigens have also been detected in CD patients. The aim of this study was to examine prospectively serologic responses to microbial targets in adult CD patients at the time of diagnosis and during a gluten-free diet (GFD). Further, we wanted to evaluate whether these serologic specificities could provide new tools for the follow-up of CD patients.

METHODS

Data on 55 adult biopsy-proven CD patients were available for follow-up study. Upper gastrointestinal endoscopy was performed on all patients. Sera from patients were tested for antibodies to tTG and ASCA and additionally analyzed with IgA enzyme-linked immunosorbent assays to Pseudomonas fluorescens-associated sequence, I2, and to a Bacteroides caccae TonB-linked outer membrane protein, OmpW.

RESULTS

At the time of diagnosis, 91% of CD cases were positive for tTG and 49% for ASCA; positive seroreactivity to I2 was found in 86% and to OmpW in 60% of CD patients at the time of diagnosis. The frequency of seropositivity and serum levels of these antibodies decreased during GFD. Moreover, we found that the decline in the serum levels was significant in all of these markers (p < 0.005). Interestingly, we also found that serum levels of ASCA correlated with the grade of mucosal morphology (p = 0.021), as the ASCA serum levels declined in accordance with mucosal healing.

CONCLUSIONS

Commensal enteric bacteria seem to play a role in the small intestinal mucosal damage in CD. This was proven by the serological responses to different microbial antigens shown in this study. Serum levels of ASCA, anti-I2, and anti-OmpW antibodies decreased significantly during GFD, indicating that these serologic markers are gluten dependent in CD patients. These specificities could provide new tools in the follow-up of CD patients.

Infiltration of forkhead box P3-expressing cells in small intestinal mucosa in coeliac disease but not in type 1 diabetes

Because the role of regulatory T cells in the intestinal inflammation is unknown in coeliac disease (CD) and type 1 diabetes (T1D), the expression of forkhead box P3 (FoxP3), CD25, transforming growth factor-beta, interferon (IFN)-gamma, interleukin (IL)-4, IL-8, IL-10, IL-15 and IL-18 was measured by quantitative reverse transcription-polymerase chain reaction in the small intestinal biopsies from paediatric patients with active or potential CD, T1D and control patients. The numbers of FoxP3- and CD25-expressing cells were studied with immunohistochemistry. Enhanced intestinal expressions of FoxP3, IL-10 and IFN-gamma mRNAs were found in active CD when compared with controls (P-values < 0.001, 0.004, <0.001). In potential CD, only the expression of IFN-gamma mRNA was increased. The numbers of FoxP3-expressing cells were higher in active and potential CD (P < 0.001, P = 0.05), and the ratio of FoxP3 mRNA to the number of FoxP3-positive cells was decreased in potential CD when compared with controls (P = 0.007). The ratio of IFN-gamma to FoxP3-specific mRNA was increased in active and potential CD (P = 0.001 and P = 0.002). Patients with T1D had no changes in regulatory T cell markers, but showed increased expression of IL-18 mRNA. The impaired up-regulation of FoxP3 transcripts despite the infiltration of FoxP3-positive cells in potential CD may contribute to the persistence of inflammation. The increased ratio of IFN-gamma to FoxP3 mRNA in active and potential CD suggests an imbalance between regulatory and effector mechanisms. The increased intestinal expression of IL-18 mRNA in patients with T1D adds evidence in favour of the hypothesis that T1D is associated with derangements in the gut immune system.

Small intestinal CD8+TCRgammadelta+NKG2A+ intraepithelial lymphocytes have attributes of regulatory cells in patients with celiac disease

Intraepithelial lymphocytes (IELs) bearing the gammadelta TCR are more abundant in the small intestinal mucosa of patients with celiac disease (CD) compared with healthy individuals. However, their role in disease pathogenesis is not well understood. Here, we investigated the functional attributes of TCRgammadelta+ IELs isolated from intestinal biopsies of patients with either active celiac disease (ACD) or those on a gluten-free diet (GFD). We found that compared with individuals with ACD, individuals on GFD have a higher frequency of CD8+TCRgammadelta+ IELs that express the inhibitory NK receptor NKG2A and intracellular TGF-beta1. TCR triggering as well as cross-linking of NKG2A increased both TGF-beta1 intracellular expression and secretion in vitro. Coculture of sorted TCRgammadelta+NKG2A+ IELs, IL-15-stimulated TCRalphabeta+ IELs, and HLA-E+ enterocytes resulted in a decreased percentage of cytotoxic CD8+TCRalphabeta+ IELs expressing intracellular IFN-gamma and granzyme-B and surface NKG2D. This inhibition was partially abrogated by blocking either TGF-beta alone or both NKG2A and HLA-E. Thus, our data indicate that suppression was at least partially mediated by TGF-beta secretion as a result of engagement of NKG2A with its ligand, HLA-E, on enterocytes and/or TCRalphabeta+ IELs. These findings demonstrate that human small intestinal CD8+TCRgammadelta+ IELs may have regulatory potential in celiac disease.

Gluten sensitivity in patients with primary Sjögren's syndrome

OBJECTIVE

To evaluate the rectal mucosal response to gluten as an indication of gluten sensitivity in patients with primary Sjögren's syndrome (pSS).

MATERIAL AND METHODS

Rectal challenges with wheat gluten were performed in 20 patients with pSS and 18 healthy control subjects. Fifteen hours after challenge the mucosal production of nitric oxide (NO) was measured.

RESULTS

Five patients with pSS had a significant increase in the luminal release of NO after the rectal gluten challenge, indicating gluten sensitivity. All were HLA-DQ2 and/or -DQ8-positive. Two of the patients with increased NO had antibodies against transglutaminase and a duodenal biopsy showed an absolutely flat mucosa consistent with coeliac disease in one of the patients. Before gluten challenge, 15 of the Sjögren's syndrome (SS) patients reported gastrointestinal symptoms, and 8 reported intolerance to various food products. No correlation was found between gluten sensitivity and self-reported food intolerance or gastrointestinal symptoms.

CONCLUSIONS

Rectal mucosal inflammatory response after gluten challenge is often seen in patients with pSS, signifying gluten sensitivity. However, this reactivity is not necessarily linked to coeliac disease.

Gamma-delta T-cell-mediated dilated cardiomyopathy

Gamma-delta T-cells are usually minor component of peripheral blood and lymphoid tissues, but may play an important role in autoimmune diseases. We here describe the first case of dilated cardiomyopathy (DCM) with heart infiltration by mostly gamma-delta T-cells, who improved significantly by steroid therapy. In general, steroid therapy has only a little effect on DCM, however these findings might have implications with respect to the selection of patients who might respond to immunosuppressive therapy.

No observed local immunological response at cell level after five years of oats in adult coeliac disease

OBJECTIVE

Our earlier 5-year follow-up study produced the first evidence to show the long-term safety of oats as part of a coeliac diet. The objective of the present study was to clarify its applicability by analysing local cellular immunological responses after 5 years' consumption of oats by adult coeliac patients.

MATERIAL AND METHODS

Forty-two coeliac patients took part in an earlier oats intervention study for 6-12 months. Twenty-two of these patients originally consumed oats as part of their gluten-free diet. During the 5-year follow-up 10 patients had felt uncertain about the safety of long-term consumption of oats and gave up this part of their diet. Finally, 12 of the 22 patients consumed oats for the whole 5-year period. The control group consisted of the remaining 20 coeliac patients using a strict, conventional, gluten-free diet without oats. Intraepithelial CD3, alphabetaTCR (alphabetaIEL) and gammadeltaTCR (gammadeltaIEL) T cells were counted after specific staining of small intestinal biopsy specimens.

RESULTS

There were no differences in the densities of CD3, alphabetaIEL and gammadeltaIEL T cells between the oat and the control groups.

CONCLUSIONS

Long-term use of oats included in the gluten-free diets of patients with coeliac disease does not stimulate an immunological response locally in the mucosa of the small intestine.

Gene dose effect of the DQB1*0201 allele contributes to severity of coeliac disease

OBJECTIVE

Coeliac disease (CD) susceptibility has been shown to be associated with the HLA alleles DQA1*0501 and DQB1*0201. This HLA-associated risk has been estimated to account for 29-40% of the genetic component of CD. Conflicting data have been published on the gene dose effect of these HLA alleles on the risk and severity of CD. In this study the aim was to investigate the association between the number of HLA risk alleles and the severity of CD.

MATERIAL AND METHODS

Fifty-four Finnish CD families, including 144 CD patients mainly diagnosed in adulthood (94.4%), were enrolled in the study. The association between the number of DQA1*0501 and DQB1*0201 alleles and villous atrophy, symptoms and laboratory parameters at the time of diagnosis, and the association with villous atrophy after one year of treatment on a gluten-free diet were studied.

RESULTS

The homozygosity for the DQB1*0201 allele was associated with a more severe form of CD assessed by more severe villous atrophy (p=0.011), younger age (p=0.036), more severe diarrhoea (p=0.048) and a lower level of blood haemoglobin at the time of diagnosis (p=0.010). Furthermore, the homozygosity for the DQB1*0201 allele was associated with a slower recovery of villous atrophy after a gluten-free diet (p=0.041). In contrast, the DQA1*0501 allele did not have a significant association with the severity of CD.

CONCLUSIONS

Our results demonstrate a gene dose effect of the DQB1*0201 allele on the clinical heterogeneity of CD and on the rate of recovery from villous atrophy in patients on a gluten-free diet.

Clinical, HLA, and small bowel immunohistochemical features of children with positive serum antiendomysium antibodies and architecturally normal small intestinal mucosa

BACKGROUND

Antiendomysium antibodies have a high sensitivity and specificity for celiac disease. A small percentage of subjects positive for these antibodies have a small intestinal mucosa hitherto considered normal.

OBJECTIVES

The aim of this study was to characterize the clinical, serological, immunogenetic, and immunohistological features of these subjects.

METHODS

From 409 patients who were positive for celiac-related antibodies, we selected 24 (5.9%) patients who had an architecturally normal small intestinal mucosa. One hundred age-matched celiac patients with a "flat" small intestinal mucosa, and 50 age-matched nonceliac children were also studied. The number of CD3+ and gammadelta+ intraepithelial lymphocytes and of CD25+ lamina propria mononuclear cells, and the expression of crypt HLA-DR and lamina propria ICAM-1 were assessed. HLA haplotyping was also performed.

RESULTS

Eleven (45.8%) of the 24 patients had a distinct infiltrative pattern, i.e., an increase in CD3+ intraepithelial lymphocytes (> 2SD of the nonceliac group), whereas 17 (70.8%) had a higher density of intraepithelial gammadelta+ cells. In 17 (70.8%) patients, the number of lamina propria CD25+ cells was increased and/or the expression of ICAM-1 and crypt HLA-DR was enhanced. All 24 patients carried the celiac disease-associated HLA haplotypes. Two of the six patients who remained on a normal diet and underwent a second jejunal biopsy developed villous atrophy.

CONCLUSIONS

Most of the patients with serum antiendomysium antibodies and normal jejunal histology showed immunohistochemical signs of immune activation in the epithelium, lamina propria, and crypts. We recommend that such patients be monitored to assess their progress and to determine whether they need a gluten-free diet.

Clinical and pathological features of 14 non-Hodgkin's lymphomas associated with coeliac disease

BACKGROUND

It is well established that enteropathy associated T-cell lymphoma is associated with malabsorption which is due to gluten sensitivity (coeliac disease). Our study was performed to define the clinical features, histological subtypes, response to treatment, and outcome of the association of coeliac disease and T-cell lymphoma.

PATIENTS AND METHODS

A retrospective study was performed in the UCL Group of Hematology to collect data on patients with a diagnosis of non-Hodgkin's lymphoma and coeliac disease. Fifteen cases were observed between 1985 and 1999. Case records for all but one patient were available and the pathological specimens of 14 patients were reviewed by two pathologists.

RESULTS

Six previously diagnosed coeliac patients developed lymphoma; interval between coeliac symptoms and onset of the lymphoma ranged from 2 to 48 years (median 16 years). Five patients had coeliac disease and non-Hodgkin's lymphoma diagnosed concomitantly or less than 6 months before the symptoms leading to the diagnosis of lymphoma. Three patients had the diagnosis of coeliac disease after lymphoma diagnosis (1, 8 and 10 years later respectively). Ten non-Hodgkin's lymphomas were of T-cell origin and 4 were B-cell lymphomas. Eight out of 14 presented on a surgical emergency. Thirteen were treated using chemotherapy. The median survival from the diagnosis of enteropathy associated T-cell lymphoma was 12 months (range 1-126).

CONCLUSIONS

Lymphomas associated with coeliac disease are heterogeneous and their diagnosis is difficult. The enteropathy-associated T-cell lymphoma is the most frequent, aggressive and fatal complication of coeliac disease but it is not rare to observe association with B-cell lymphoma. Chemotherapy is highly toxic in those patients. Despite a poor prognosis, long-term survival can be expected in a fraction of these patients.

Emerging role of gammadelta T-cells in health and disease

The majority of T lymphocytes in the peripheral blood bear the alphabeta type of T-cell receptor (TCR) and less than 5% of circulating T lymphocytes bear the gammadelta type of TCR. The alphabeta and gammadelta T-cells contribute differently to the host immune defense. The immunologic function of gammadelta T-cell in humans is gradually unraveling. Pathologic studies have shown a relatively high proportion of gammadelta T-cells in the gastrointestinal mucosa, skin, and splenic red pulp where they appear to have an important immunologic function against pathogens attempting to enter body through the mucosal surfaces and possibly the skin. More data are emerging about the role of gammadelta T-cells in the course of infectious diseases and in the pathogenesis of autoimmunity. The possible role of these cells in immunologic surveillance against cancer has been inferred from their preferential expansion in certain malignancies. In parallel to the low frequency of these cells in normal lymphocytes, lymphomas bearing gammadelta type of T-cell receptors on cell surface are rare. These include hepatosplenic and non-hepatosplenic (including those involving the skin and those involving nasal cavity and upper aero digestive tract) and the rare non-B-cell cases of lymphomas seen in the immunosuppressed organ transplant patients. The limited available clinical data about gammadelta T-cell lymphomas suggest that these lymphomas tend to have an aggressive course particularly the hepatosplenic form with poor response to multi-agent chemotherapy and short median survival.

Is a raised intraepithelial lymphocyte count with normal duodenal villous architecture clinically relevant?

BACKGROUND

A raised intraepithelial lymphocyte (IEL) count with normal villous architecture is a recognised finding in latent coeliac disease. Little information is available in cases without gluten sensitive enteropathy in adults.

AIMS

To assess the frequency of such a finding in routine practice and to determine whether it is clinically relevant.

METHODS

Patients with subjectively increased IELs as the only abnormality were identified prospectively from a routine duodenal biopsy series over a 12 month period. The biopsy specimens in these index cases were re-examined together with two controls with normal histology for each case, and three counts of IEL/100 epithelial cells were made in all samples. The index cases were then contacted and interviewed to obtain clinical information, approximately 12 months from the initial biopsy. Further data were obtained from their clinical records.

RESULTS

Fourteen of 626 (2.2%) patients who had duodenal biopsies over the 12 month period had a subjective increase in IELs with normal villous architecture. Fifteen patients with newly diagnosed gluten sensitive enteropathy were also identified during the study period. Formal counting of the index cases and controls revealed a significant difference in IELs/100 epithelial cell counts between the two (mean, 38 (SD, 6.2) v 12.4 (4.6); p < 0.0001). Three of the 14 index cases tested had a positive coeliac antibody test compared with 12 of 15 newly diagnosed patients with coeliac disease and 10 of 93 patients with normal histology. The major clinical diagnostic categories in raised IEL cases were those with positive coeliac serology (n = 3), unexplained anaemia (n = 3), and chronic liver disease (n = 3). Six of 10 patients who were interviewed had ongoing gastrointestinal symptoms one year later. Three patients had had follow up duodenal biopsies, at the discretion of their responsible clinicians, with no change in IEL counts despite the commencement of a gluten free diet in two patients.

CONCLUSION

A raised IEL count with normal villous architecture is not uncommon. Six of the 14 patients may have had latent coeliac disease. The cause in at least half of cases is not obvious at present. The finding of a raised IEL count with normal villous architecture is of sufficient clinical importance to be highlighted in routine duodenal biopsy reports.

Inflammatory cytokines in small intestinal mucosa of patients with potential coeliac disease

T helper cell type 1 (Th1) response to gluten has been implicated in the pathogenesis of coeliac disease (CD). To characterize immunological activation and mild inflammations leading to overt CD in potential coeliac patients, jejunal biopsies were obtained from family members of patients with CD or dermatitis herpetiformis (DH). Nine family members and one latent CD, eight CD patients and eight normal controls furnished jejunal biopsy specimens. Immunohistochemical staining of sections for interleukin-1alpha (IL-1alpha), IL-2, IL-4, interferon-gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), CD3, gammadelta-T cell receptor (gammadelta-TCR), and alphabeta-TCR was carried out with monoclonal antibodies. Further, expression of IL-4 and IFN-gamma messenger RNA was detected by radioactive in situ hybridization in these same samples. In lamina propria, CD patients and potential CD patients had higher densities of IL-2 (P = 0.028, P = 0.043), IL-4 (P = 0.021, P = 0.034) and IFN-gamma positive cells (P = 0.000, P = 0.009) than did controls. Moreover, CD patients showed a higher density of TNF-alpha positive cells (P = 0.012, P = 0.001) than the other two groups, and expression of IFN-gamma mRNA (P = 0.035) was higher in them than in the other two study groups. Additionally, higher densities of TNF-alpha and IFN-gamma positive cells occurred in potential CD patients with high gammadelta-TCR+ intraepithelial lymphocytes (IELs). Our findings support the hypothesis that lamina propria T cells and macrophages, through their secretion of cytokines, play a central role in the pathogenesis of coeliac disease. The inflammatory cytokines found in potential CD specimens strongly suggest that these inflammatory markers can be identified long before visible villous changes have occurred.

Lymphonodular hyperplasia of the terminal ileum associated with colitis shows an increase gammadelta+ t-cell density in children

OBJECTIVE

Recently we reported a close association between lymphonodular hyperplasia (LNH) of the bulb of the duodenum and increased densities of intraepithelial gammadelta+ T-cells in subjects with untreated food allergies. In this study we sought to determine whether children with LNH of the terminal ileum (TI) show a similar correlation.

METHODS

The mucosal specimens taken by colonoscopy from the TIs of 22 children with LNH of the TI without colitis, 13 with right-sided colitis or pancolitis, nine with left-sided colitis, eight with Crohn's disease, and three endoscopically healthy subjects were studied for T-cell subsets with monoclonal antibodies using a three-layer peroxidase staining method.

RESULTS

LNH of the TI was found in 32 of the 55 subjects (58%). In 22 it was the only endoscopic finding, but in nine of 13 subjects (69%) it was related to right-sided colitis or pancolitis. In patients with left-sided colitis or Crohn's disease it was diagnosed only rarely. In the whole study population, LNH of the of the TI showed a significant association with the increment in the density of gammadelta+ T-cells. The subjects with LNH of the TI and colitis starting from the cecum showed the highest values, discriminating them statistically from any other study group. Accordingly their gammadelta+/CD3+ ratio was high. Even in the subjects with LNH of the TI without colitis, the increment in gammadelta+ T-cells was significant as compared with the subjects with left-sided colitis. Upregulations of D-related expression on the mucosa of the TI were similar regardless of the presence of LNH or colitis or an increment in gammadelta+ T-cells.

CONCLUSION

Our preliminary observations showed increased densities of intraepithelial gammadelta+ T-cells and elevated gammadelta+/CD3+ ratios in subjects with LNH on the mucosa of the TI, especially if related to colitis starting at the cecem, but not in subjects with typical left-sided colitis or granulomatous Crohn's disease. The study also provides further evidence suggesting the significance of food-borne antigens in the pathogenetic mechanism of right-sided colitis or pancolitis. The finding also indicates the significance of classifying colitis into gammadelta-positive and -negative diseases, and has implications for the treatment of these entities.

Potential and latent coeliac disease

This case report details a child with coeliac disease and giardiasis. Treatment of the infection without recourse to a gluten-free diet cured the symptoms of diarrhoea and returned the small intestinal morphology to normal. Thus, the patient moved from active to latent coeliac disease. Potential and latent forms of coeliac disease are being increasingly recognized, since markers have become available to identify patients and investigations developed to test for gluten sensitivity in the small intestinal mucosa. This case provides an opportunity to consider potential and latent forms of coeliac disease and how these impact on clinical practice and the wider understanding of the disorder.

Children with untreated food allergy express a relative increment in the density of duodenal gammadelta+ T cells

BACKGROUND

We investigated whether children with food allergy (FA) express increased densities of intraepithelial gammadelta+ T cells similarly to subjects with celiac disease.

METHODS

The duodenal specimens taken by gastroduodenoscopy from 20 children with untreated FA, 17 with treated FA, 12 with celiac disease (CD) and 12 controls were studied with monoclonal antibodies and a three-layer peroxidase staining method.

RESULTS

The subjects with untreated FA expressed equal densities of total intraepithelial CD3+ and alpha/beta+ T cells, but significantly higher densities of gammadelta+ cells than the subjects currently on an elimination diet for FA or the controls. Accordingly, their gammadelta+/CD3+ ratio was higher. On the other hand, the results differed clearly from CD, where all the three cell populations showed high densities. Another finding that discriminated the subjects with FA from the CD patients was endoscopic examination. Lymphonodular hyperplasia (LNH) of the duodenal bulb with a normal villous pattern was demonstrated in 14 (70%) of the 20 subjects with untreated FA and in 8 (47%) of the 17 with treated FA, but in none of the celiac patients or controls. Surprisingly, the biopsy samples from the subjects with FA showed quite normal histological findings.

CONCLUSIONS

According to this preliminary observation, high densities of intraepithelial gammadelta+ T cells and a significantly elevated gammadelta+/CD3+ ratio are associated with untreated FA. If seen LNH in a gastroduodenoscopy and/or increased densities of gammadelta+ T cells in the biopsy specimen, the possibility of gastrointestinal FA should be reliably assessed by a food challenge.

Histopathology of celiac disease

The diagnosis of celiac disease (CD) is based upon histologic findings in duodenal or jejunal biopsies. In the past few years it has turned out that the development of CD lesion in the small bowel is a dynamic process which may present in various histologic forms. At one end of the spectrum is a mucosa with normal architecture and an increase in intraepithelial lymphocytes (IEL), at the other end is the classical flat mucosa. Histologic features supporting the diagnosis of CD are architectural changes of the villi and/or crypts, an increase in lamina propria cell density and an increase in IEL counts. For diagnostic purposes and for monitoring CD patients an exact histologic classification of the histologic findings has to be given. This has become possible by using a modified Marsh classification. In the present paper the histologic presentation of CD is presented as well as the modified Marsh classification.

Refractory celiac disease

Celiac disease is a gluten-sensitive enteropathy, characterized by villous atrophy, which is reversed by gluten withdrawal. A minority of patients with celiac-like enteropathy are resistant to gluten-free diet, so-called refractory sprue, or unclassified sprue. Refractory sprue is a diagnosis of exclusion; all other causes of a celiac-like enteropathy must be eliminated before a diagnosis of refractory sprue can be made. Recent evidence suggests that refractory sprue comprises a heterogenous group of patients with diverse underlying causes. A small proportion of these patients seem to have an adult form of autoimmune enteropathy, characterized by the presence of antienterocyte antibodies. However, a larger group of patients with refractory sprue now seem to have a cryptic intestinal T-cell lymphoma, characterized by the presence of phenotypically abnormal, monoclonal intraepithelial lymphocytes, despite benign cytology. Current therapeutic options include nutritional support and immunosuppressive therapy, but response is variable. The prognosis of refractory sprue may be poor; patients may die of severe malabsorption, or through synchronous or metachronous development of an enteropathy-associated T-cell lymphoma. Based on this recent evidence, patients with refractory sprue should be screened for antienterocyte antibodies and have T-cell receptor and monoclonal antibody studies performed; this could facilitate identification of cases of adult-onset autoimmune enteropathy and those of cryptic T-cell lymphoma. Moreover, early recognition of the malignant nature of the intestinal infiltrate in some cases of refractory sprue could permit the development of novel chemotherapeutic regimens for this condition.

Cytolytic mechanisms of intraepithelial lymphocytes in coeliac disease (CoD)

The effector arm of the mucosal immune system comprises lymphocytes scattered at intraepithelial and lamina propria levels. Intraepithelial lymphocytes (IEL) are a large population of oligoclonal resting cells which exhibit phenotypic and functional characteristics of cytolytic T cells when activated. Several mechanisms have been demonstrated to account for their cytotoxicity. Among them, one is mediated by perforin and granzyme molecules, another is mediated by Fas ligand (FasL) which delivers apoptotic signals through Fas receptor on target cells. There is good evidence that a flat intestinal mucosa may be produced by activated T cells. The aim of our study was to evaluate FasL and perforin expression by IEL, and its possible correlation with the increased enterocyte apoptosis in coeliac mucosa. Endoscopic duodenal biopsy specimens from 10 untreated coeliac patients, 10 treated coeliac patients, and 10 biopsied controls were evaluated for enterocyte apoptosis by terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine triphosphate nick end label method, for perforin expression by immunohistochemistry, and for FasL expression by immunocytochemistry. In untreated CoD there was a significant increase of percentage of both FasL+ and perforin+ IEL which positively correlated with enterocyte apoptosis in comparison with controls. All these parameters were significantly lower in treated CoD, even though they did not normalize. Our study demonstrates that in untreated CoD FasL and perforin expression by IEL is increased, and significantly correlates with the level of enterocyte apoptosis.

Local challenge of oral mucosa with gliadin in patients with coeliac disease

In coeliac disease, gluten-containing diet challenges over many years are sometimes required for diagnosis, especially if the initial diagnosis was equivocal. The rectal gluten challenge has been proposed to simplify coeliac disease diagnosis. We were interested in studying whether the oral mucosa could be used for local challenge with gliadin as an aid in finalizing the diagnosis of coeliac disease. The study groups consisted of 37 treated coeliac disease patients and 10 controls. The challenges on the oral mucosa were performed either supramucosally with gliadin powder (coeliac disease patients) or by submucosal injection of dissolved gliadin (10 microg/ml) (coeliac disease patients and controls). A control challenge with submucosal gliadin solvent was made in the coeliac disease patients. B and T cells, mast cells and T cell subsets were counted and HLA-DR expression was determined. Biopsies were taken from each provoked area 24 h post-challenge. A significant increase in the number of CD4+ lymphocytes in the lamina propria (observed in 27/37 patients), but a decrease in the number of mast cells was observed in treated coeliac disease patients after submucosal challenge with gliadin. Following supramucosal challenge with gliadin the counts of intraepithelial CD4+ (in 25/37 patients) and CD8+ T cells (in 27/37 patients) increased significantly and the number of CD4+ T cells in the lamina propria was also significantly increased. Control subjects were tested by submucosal gliadin challenge and no significant changes in the number of cells were observed. HLA-DR expression did not show increased positivity in coeliac disease patients on submucosal challenge. For the first time the oral mucosa has been used for immunological testing and shown to react to gliadin challenge in coeliac disease patients. Recruitment of T cells upon submucosal gliadin challenge occurred towards the lamina propria, whereas it occurred towards the epithelium in supramucosal gliadin challenge. The numbers of T cells increased in the lamina propria after submucosal challenge. The results suggest that local oral challenge with gliadin may be used as a diagnostic method in coeliac disease; however, further studies in untreated coeliac disease patients are needed to evaluate the usefulness of this method.

The natural history of gluten sensitivity: report of two new celiac disease patients resulting from a long-term follow-up of nonatrophic, first-degree relatives

OBJECTIVE

Early studies revealed that up to 50% of non-atrophic, first-degree relatives of celiac disease patients exhibit features of gluten sensitivity. However, whether these features progress to a fully expressed celiac disease remain partially known. Our aim was to report two new patients resulting from a prospective, long-term surveillance of relatives who were nonatrophic at initial assessment.

METHODS

After a median time of 86 months (range: 42-102 months) from the baseline assessment, we re-evaluated 44 first-degree relatives of propositi who had taken part in family studies and in whom baseline small intestinal biopsies were normal. At the baseline screening, 21 relatives had positive serum antigliadin antibodies and/or increased intraepithelial lymphocyte infiltration, and 23 did not. In addition, 11 of 18 had a celiac-like response to rectal gluten challenge and 16 of 34 possessed the characteristic HLA DQ2 haplotype (DQA1 0501 DQB1 0201). Re-evaluation was based on celiac-related serology antigliadin (AGA) and endomysial (EmA) antibodies. EmA-positive subjects underwent intestinal biopsy.

RESULTS

At the end of the study, EmA was positive in only two subjects. Histological examination revealed flat small bowel mucosa in both. At baseline, both cases were EmA-negative and no minor histological changes were observed. One was a woman with positive baseline IgA and IgG AGA and a rectal gluten challenge with a celiac-like response; the other patient has presented only with a positive IgG AGA. In both cases, progression was detected in a clinically silent context. Both new patients had the characteristic HLA DQ2 haplotype.

CONCLUSIONS

Our data suggest the need to re-evaluate relatives who have been negative on initial screening for celiac disease. Up to now, the progression to severe enteropathy was only observed in relatives who had presented some evidence of gluten sensitivity and the characteristic HLA DQ2 haplotype. Longer longitudinal studies are necessary to obtain definitive conclusions.

Food-induced malabsorption syndromes

A syndrome of chronic diarrhea, vomiting, and failure to thrive was described 35 years ago. The syndrome was caused by damage in the jejunum after ingestion of cow's milk. Symptoms appeared in young infants shortly after introduction of cow's milk formula. Patients had moderate steatorrhea, decreased absorption of D-xylose, and, often, iron-deficiency anemia and hypoproteinemia. They had strong IgA and IgG antibodies to cow's milk. IgE antibodies to cow's milk were negative, as a rule. Indicators of cell-mediated immune reaction to cow's milk proteins were often positive. Patients were tolerant to cow's milk by the age of 3 years. Malabsorption was due to damage to the jejunal mucosa: Varying villus atrophy was associated with inflammation in surface epithelium and lamina propria. The epithelial cell renewal rate increased. Surface epithelial cells decreased in height, with short, furry microvilli and large aggregates of lysozymes. The number of intraepithelial lymphocytes was markedly increased, but normalized during cow's milk elimination. Most of these lymphocytes had alpha/beta T-cell receptors, and many were cytotoxic. Some specimens had an increase in gamma/delta T-cell receptor-bearing cells. In the lamina propria, CD4+ cells predominated, and some of them were activated. IgA- and IgM-containing cells were markedly increased during cow's milk exposure, but IgE cells were not abnormal. The density of eosinophils was moderately increased. Secretion of interferon-gamma by cells isolated from patients' intestines was markedly increased. Morphologic and immunologic findings suggest that T-cell-mediated reaction to proteins in cow's milk is present in the small intestines of patients with this syndrome and causes this enteropathy.

Expression of HSP-65 in jejunal epithelial cells in patients clinically suspected of coeliac disease

BACKGROUND

Coeliac disease (CD) can be classified both clinically and biologically an autoimmune disease. A close relationship obtains between heat shock proteins (HSPs) and numerous autoimmune diseases. HSPs are overexpressed when protecting the host against environmental insult. We sought here to establish whether dietary gluten is such a stress stimulus in patients clinically suspected of CD, and whether the expression of HSP-65 associates with densities of intraepithelial gammadelta+ T cells and/or with expression of mucosal HLA-DR.

METHODS

Seventy-eight children with clinical suspicion of CD underwent a jejunal biopsy. Monoclonal antibodies were used to stain jejunal epithelial HSP-65, intraepithelial lymphocytes and mucosal HLA-DR. Serum IgA-class endomysial autoantibodies (EMA) were measured by an indirect immunofluorescence method. CD susceptibility HLA DQA1*0501 and DQB1*0201 alleles (HLA DQ2) were determined.

RESULTS

Enhanced expression of epithelial cell mitochondrial HSP-65 was found in 80% (16/20) of coeliacs and in 24% (14/58) of children excluded for the disease, but in only 7% (2/28) of control subjects (p < 0.001, p = 0.049, respectively). Children with enhanced expression of HSP-65 had significantly higher gammadelta+ T cell densities than those with normal HSP-65 expression. A clear association between HSP-65 and serum IgA-class EMA were also ascertained in patients with normal jejunal mucosal morphology. HLA DQ2 positivity did not correlate with the HSP-65 expression.

CONCLUSIONS

Gluten might be an environmental insult not only in CD patients but also in some patients excluded for the disease on biopsy. Enhanced expression of epithelial cell stress proteins might be an indicator of such an insult.

Increased density of jejunal gammadelta+ T cells in patients having normal mucosa--marker of operative autoimmune mechanisms?

Both from a clinical and a biological point of view, coeliac disease can be classified among the autoimmune diseases, or one could suspect autoimmune mechanisms to be operative in the disease. The aim of the present study was to find evidence for mucosal markers of coeliac disease latency in patients clinically suspected but on routine biopsy excluded for the disease. Monoclonal antibodies were used to stain jejunal intraepithelial lymphocytes and mucosal HLA-DR. Serum IgA-class reticulin autoantibodies were measured by an indirect immunofluorescence and gliadin antibodies by an enzyme-linked immunosorbent assay method. The DQA1*0501 and DQB1*0201 alleles were determined. Twenty-seven of 107 consecutive patients had coeliac disease. Altogether 39 of 79 (49%) children with normal jejunal mucosa had an increased density of intraepithelial gammadelta+ T cells (> or = 4.4 cells/mm). IgA-class reticulin autoantibodies were positive in 18 (23%) of the children excluded for coeliac disease. The antibody positivity was mostly seen in patients carrying the DQAI 0501 and DQB1*0201 alleles. Also, reticulin autoantibody-positive children having normal jejunal mucosal morphology had significantly higher densities of intraepithelial gammadelta+ T cells than antibody negative ones. On 1.5-4.5 year follow-up four out of 18 (22%) children primarily excluded for coeliac disease showed mucosal deterioration and coeliac disease. Many patients clinically suspected of coeliac disease but having normal jejunal mucosa show markers of coeliac disease latency which may be gluten-induced indicating autoimmune mechanisms to be operative in the gut.

Changing jejunal gamma delta T cell receptor (TCR)-bearing intraepithelial lymphocyte density in coeliac disease

The function of jejunal intraepithelial gamma delta+ T cells is obscure, but they are commonly implicated as playing a role in inflammatory and autoimmune conditions. In coeliac disease (CoD), there are controversial reports as to gluten dependency of these cells. We have now studied the small bowel mucosal intraepithelial T cell densities, and the ratios of gamma delta+ to CD3+ T cells and gamma delta+ to alpha beta+ T cells during early disease development and on a gluten-free diet. Nine children initially excluded for CoD were followed up and rebiopsy after 0.8-4.5 years showed mucosal deterioration. Further, 21 biopsy specimens from newly diagnosed CoD patients were studied, together with 20 specimens taken from children on a gluten-free diet. During CoD development the density of gamma delta+ and alpha beta+ T cells as well as the ratios of gamma delta+ to CD3+ T cells and gamma delta+ to alpha beta+ T cells increased. In the latent stage of CoD when the small bowel mucosal architecture was still normal, two children had clearly normal densities of gamma delta+ (< 2.5 cells/100 epithelial cells) and alpha beta+ (< 25.0 cells/100 epithelial cells) T cells, and low ratios as well. In patients with newly diagnosed CoD the densities decreased significantly on a long-term gluten-free diet. We conclude that the density of intraepithelial gamma delta+ T cells as well as alphabeta+ T cells in CoD is gluten-dependent. CoD can develop in a child ingesting normal amounts of gluten and having normal jejunal mucosal morphology on biopsy and a normal density of gamma delta+ T cells.