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

Biological variability of human intraepithelial lymphocytes throughout the human gastrointestinal tract in health and coeliac disease

BACKGROUND

Intraepithelial lymphocytes are the first line of defence of the human intestinal immune system. Besides, their composition is altered on patients with coeliac disease (CD), so they are considered as biomarkers with utility on their diagnose and/or monitoring. Our aim is to address their variability through the human gastrointestinal tract in health and characterized them in further depth in the coeliac duodenum.

METHODS

Intraepithelial lymphocytes were isolated from human gastric, duodenal, ileal and colonic biopsies, then stained with specific antibodies and acquired by flow cytometry.

RESULTS

Our results confirmed that the profile of Intraepithelial lymphocytes change through the length of the human gastrointestinal tract. Besides and given the central role that Interleukin-15 (IL-15) elicits on CD pathogenesis; we also assessed the expression of its receptor revealing that there was virtually no functional IL-15 receptor on duodenal Intraepithelial lymphocytes. Nevertheless and contrary to our expectations, the active IL-15 receptor was not increased either on Intraepithelial lymphocytes from CD patients.

CONCLUSIONS

IL-15 might require additional stimulus to activate intraepithelial lymphocytes. These findings may provide novel tools to aid on a CD diagnosis and/or monitoring, at the time that provide the bases to perform functional studies in order of getting a deeper insight in the specific function that Intraepithelial lymphocytes elicit on CD pathogenesis.

γδ+ T-Cells Is a Useful Biomarker for the Differential Diagnosis between Celiac Disease and Non-Celiac Gluten Sensitivity in Patients under Gluten Free Diet

BACKGROUND

The differential diagnosis between patients with celiac disease (CD) and non-celiac gluten sensitivity (NCGS) is difficult when a gluten-free diet (GFD) has been initiated before the diagnostic work-up. Isolated increases in TCRγδ+ and celiac lymphogram (increased TCRγδ+ plus decreased CD3-) may enable differential diagnosis in this challenging clinical setting. This study evaluated: (1) the accuracy of %TCRγδ+ and celiac lymphogram for diagnosing CD before and after GFD and for differentiation with NCGS; (2) TCRγδ+ kinetics at baseline and after starting GFD in both CD and NCGS.

METHODS

The inclusion criteria were patients with CD (n = 104), NCGS (n = 37), and healthy volunteers (n = 18). An intestinal biopsy for intraepithelial lymphogram by flow cytometry was performed at baseline and after GFD. The optimal cutoff for CD diagnostic accuracy was established by maximizing the Youden index and via logistic regression.

RESULTS

%TCRγδ+ showed better diagnostic accuracy than celiac lymphogram for identifying CD before and after GFD initiation. With a cutoff > 13.31, the accuracy for diagnosing CD in patients under GFD was 0.88 [0.80-0.93], whereas the accuracy for diagnosing NCGS (%TCRγδ+ ≤ 13.31) was 0.84 [0.76-0.89]. The percentage of TCRγδ+ cells showed differential kinetics between CD (baseline 22.7% [IQR, 16.4-33.6] vs. after GFD 26.4% [IQR, 17.8-36.8]; p = 0.026) and NCGS (baseline 9.4% [IQR, 4.1-14.6] vs. after GFD 6.4% [IQR, 3.2-11]; p = 0.022).

CONCLUSION

TCRγδ+ T cell assessment accurately diagnoses CD before and after a GFD. Increased TCRγδ+ was maintained in the long term after GFD in CD but not in NCGS. Altogether, this suggests the potential usefulness of this marker for the differential diagnosis of these two entities in patients on a GFD.

The Usefulness of Intraepithelial Lymphocyte Immunophenotype Testing for the Diagnosis of Coeliac Disease in Clinical Practice

BACKGROUND

The diagnosis of coeliac disease (CD) in adults is based on clinical, serological and histological criteria. The inappropriate performance of intestinal biopsies, non-specificity of mild histological lesions and initiation of a gluten-free diet (GFD) before biopsy may hamper the diagnosis. In these situations, determining the intraepithelial lymphogram of the duodenum by flow cytometry (IEL-FC) can be helpful.

OBJECTIVES

To describe the clinical scenarios in which the IEL-FC is used and its impact on the diagnosis of CD.

METHODS

All adult patients with suspected CD at three tertiary centres for whom the duodenal histology and IEL-FC were available were identified. Catassi and Fasano's diagnostic criteria and changes to a CD diagnosis after the IEL-FCs were collected.

RESULTS

A total of 348 patients were included. The following indications for an IEL-FC formed part of the initial study for CD (38%): negative conventional work-up (32%), already on a GFD before duodenal biopsies (29%) and refractoriness to a GFD (2%). The IEL-FC facilitated a definitive diagnosis in 93% of patients with an uncertain diagnosis who had had a conventional work-up for CD or who were on a GFD before histology.

CONCLUSIONS

The IEL-FC facilitates the confirmation or rejection of a diagnosis of CD in clinical scenarios in which a conventional work-up may be insufficient.

Flow cytometry for the assessment and monitoring of aberrant intraepithelial lymphocytes in non-responsive celiac disease and non-celiac enteropathies

BACKGROUND

Few data are available on flow cytometry (FC) for monitoring intraepithelial lymphocytes (IELs) in refractory celiac disease (RCD), non-responsive celiac disease (NRCD), and non-celiac enteropathies (NCEs).

AIMS

1) To investigate the significance of monitoring IELs immunophenotype with FC in patients with NRCD, RCD and NCEs; 2) to evaluate FC concordance with immunohistochemistry (IHC) and γ-TCR clonality analysis.

METHODS

Patients investigated between January-2012 and February-2023 were divided into two groups: 1)confirmed RCD or NRCD being investigated for persistent symptoms and suspected complications of celiac disease (CD); 2)NCEs lacking clinical/histological response. Clinical/molecular features and outcomes were retrospectively collected and analysed according to presence/absence of aberrant IELs on FC (cut-off≥20 % CD103+sCD3-CD8-iCD3+ IELs).

RESULTS

52 patients (18 RCD,21 NRCD,13 NCEs; 38F, 55±13 years; median follow-up 30 months, IQR 2-58) underwent 100 FC IELs determinations. 22/52 had ≥2 FC determinations and IEL phenotype remained unchanged over time in all them (κ=1.00). Aberrant IEL phenotype in CD was associated with increased mortality (HR 4.2, 95 % CI 1.5-11.9, p < 0.01). No patients with NCEs had an aberrant IEL phenotype at FC, although 3/13 developed lymphoma and 4/13 died. Concordance of FC was fair with both IHC (κ=0.40) and γ-TCR clonality analysis (κ=0.22).

CONCLUSION

FC is accurate for assessing and monitoring IEL phenotype and providing important prognostic information in celiac patients. Further study is needed on its role in NCEs.

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.

Improving the Diagnosis of Dermatitis Herpetiformis Using the Intraepithelial Lymphogram

Dermatitis herpetiformis is a cutaneous manifestation of celiac disease. Phenotyping of intraepithelial lymphocytes in the small bowel mucosa can strengthen the diagnosis of celiac disease when it is not clear-cut. We aim to evaluate the usefulness of the intraepithelial lymphogram to confirm dermatitis herpetiformis in equivocal cases. We performed a retrospective multicenter study on patients diagnosed with dermatitis herpetiformis and collected data from the intraepithelial lymphogram assessed by flow cytometry. A total of 36 patients were analyzed in relation to the severity of intestinal damage (18 had non-atrophic mucosa) at baseline (N = 28) and/or after the adoption of a gluten-free diet (median follow-up of three years, N = 16). We observed that patients with atrophy more often had positive celiac serology (p = 0.019), celiac clinical symptoms (p = 0.018), and iron-deficiency anemia (p = 0.018), but the severity of skin damage was similar in both groups (p = 0.79). At baseline, increased TCRγδ+ cells were present in 94% of patients with atrophy and 67% with non-atrophic lesions (p = 0.13). After a gluten-free diet, increased TCRγδ+ cells persisted in 100% and 63% of cases, respectively (p = 0.21). We concluded that increased TCRγδ+ cells may be helpful in confirming the diagnosis of dermatitis herpetiformis in equivocal cases, even in patients who were started on a gluten-free diet.

Flow cytometric analysis of duodenal intraepithelial lymphocytes (celiac lymphogram): A diagnostic test for celiac disease

Celiac disease (CD) diagnosis in adults and certain cases of children mainly relies on the assessment of histopathological features in duodenal biopsies. However, none of the histological findings that characterize CD are pathognomonic. This, in addition to the clinical heterogeneity of the disease and the presence of seronegative forms, makes the diagnosis of CD still a challenge. A hallmark of the celiac mucosa is the elevated number of TCRγδ intraepithelial lymphocytes (IEL) in the epithelium, which may remain increased even long after gluten withdrawal. Active disease is also characterized by the decreased CD3- IEL subset. The use of flow cytometry enables a precise cell counting and phenotyping, allowing the ascertainment of both TCRγδ+ and CD3- IEL subsets, what is known as the "IEL lymphogram." Although determination of this lymphogram has become a routine evaluation tool in numerous hospitals, standardization of the technical method will guarantee an accurate performance in order to become a pivotal technique for CD diagnosis. Here we describe the protocol to process duodenal biopsies in order to obtain the IELs from the mucosa and to characterize lymphocyte populations by flow cytometry to obtain the IEL lymphogram.

Intestinal and blood lymphograms as new diagnostic tests for celiac disease

Accurate celiac disease (CD) diagnosis is still challenging for some specific patients or circumstances. Thus, much effort has been expended last decades focused on seronegative or low grade enteropathy CD and, especially, on enable early diagnosis of individuals on a gluten-free diet (GFD). We discuss here two diagnostic approaches based on immunophenotyping by flow cytometry that we expect to reduce the persistent low diagnostic rates and the common diagnostic delay. The intraepithelial lymphogram is based on determining the percentage of TCRγδ+ and surface CD3- lymphocytes in the intestinal epithelium. The concomitant increase in TCRγδ+ and decrease in surface CD3- intraepithelial lymphocytes has been termed the celiac lymphogram and has been proved to be discriminative in seronegative, low grade enteropathy and potential CD, as well as in most CD patients on a GFD. A blood lymphogram based on the analysis of activated gut-homing CD8+ T cells combined with a 3-day gluten challenge is also considered, which has shown high sensitivity and specificity to diagnose seropositive Marsh 1 and Marsh 3 CD in individuals following a GFD. In addition, flow cytometry can be extremely useful in cases of refractory CD type II to identify aberrant cells. Those approaches represent highly accurate methods for CD diagnosis, being simple, fast, highly reproducible and of easy implementation in clinical practice.

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.

Intestinal Cellular Biomarkers of Mucosal Lesion Progression in Pediatric Celiac Disease

Celiac disease (CD) is a chronic intestinal inflammation caused by gluten ingestion in genetically predisposed individuals. Overt-CD and potential-CD are the two main forms of gluten intolerance in pediatric patients with different grades of intestinal mucosa lesion and clinical management. For overt-CD patients the gluten-free diet is mandatory, while for potential-CD the dietary therapy is recommended only for those subjects becoming clinically symptomatic overtime. To date, specific early biomarkers of evolution to villous atrophy in potential-CD are lacking. We recently observed an expansion of TCRγδ+ T cells and a concomitant disappearance of IL4-producing T cells in the intestinal mucosa of overt-CD patients compared to potential-CD children, suggesting the involvement of these two cells subsets in the transition from potential-CD to overt-CD. In this study, we demonstrated that the intestinal densities of IL4+ T cells inversely correlated with TCRγδ+ T cell expansion (p < 0.005) and with the serum levels of anti-tissue transglutaminase antibodies (p < 0.01). The changes of these two cell subsets strongly correlated with mucosal lesions, according to the histological Marsh classification, as the transition from M0 to M3 lesions was associated with a significant reduction of IL4+ T cells (M0 vs. M1 p < 0.04, M0 vs. M3 p < 0.007) and an increase of TCRγδ+ T cells (M0 vs. M1 p < 0.05, M0 vs. M3 p < 0.0006). These findings strongly suggest that the detection of TCRγδ+ and IL4+ T cells could serve as cellular biomarkers of mucosal lesion and targets of novel immunomodulatory therapies for CD.

Activated gut-homing CD8+ T cells for coeliac disease diagnosis on a gluten-free diet

BACKGROUND

The diagnosis of coeliac disease (CD) in individuals that have started a gluten-free diet (GFD) without an adequate previous diagnostic work-out is a challenge. Several immunological assays such as IFN-γ ELISPOT have been developed to avoid the need of prolonged gluten challenge to induce the intestinal damage. We aimed to evaluate the diagnostic accuracy of activated gut-homing CD8⁺ and TCRγδ⁺ T cells in blood after a 3-day gluten challenge and to compare it with the performance of IFN-γ ELISPOT in a HLA-DQ2.5 subsample.

METHODS

A total of 22 CD patients and 48 non-CD subjects, all of them following a GFD, underwent a 3-day 10-g gluten challenge. The percentage of two T cell subsets (CD8⁺ CD103⁺ β7^hi CD38⁺/total CD8⁺ and TCRγδ⁺ CD103⁺ β7^hi CD38⁺/total TCRγδ⁺) in fresh peripheral blood drawn baseline and 6 days after the challenge was determined by flow cytometry. IFN-γ ELISPOT assays were also performed in HLA-DQ2.5 participants. ROC curve analysis was used to assess the diagnostic performance of the CD8⁺ T cell response and IFN-γ ELISPOT.

RESULTS

Significant differences between the percentage of the two studied subsets of CD8⁺ and TCRγδ⁺ cells at days 0 and 6 were found only when considering CD patients (p < 10^-3 vs. non-CD subjects). Measuring activated CD8⁺ T cells provided accurate CD diagnosis with 95% specificity and 97% sensitivity, offering similar results than IFN-γ ELISPOT.

CONCLUSIONS

The results provide a highly accurate blood test for CD diagnosis in patients on a GFD of easy implementation in daily clinical practice.

Diagnosing coeliac disease: A literature review

Coeliac disease (CD) is an autoimmune gastroenteropathy triggered by gliadin and gliadin-tissue transglutaminase (tTG) complexes. CD is one of the few autoimmune diseases with an accurate, non-invasive serological test. Anti-endomysial, anti-tTG and anti-deaminated gliadin peptides (DGP) antibodies are currently used for serological tests with tTG ELISAs being the superior test. Duodenal biopsy, although invasive, is the gold standard for CD diagnosis. HLA genotyping and flow cytometry can also be used as supplementary tests. The incidence of CD is rising globally although the reasons for this remain unclear. In addition, the true incidence of coeliac disease in African populations remains unknown although recent work suggests that South African populations express the alleles associated with this disease. This review examines the pathogenesis and diagnosis of coeliac disease and considers novel and innovative biomarkers in its diagnosis specifically in an African population.

Coeliac Disease in Elderly Patients: Value of Coeliac Lymphogram for Diagnosis

(1) Background: Although a meta-analysis reported that the sensitivity of CD3+ TCRγδ+ cells for coeliac disease diagnosis was >93%, a recent study has suggested that sensitivity decreased to 65% in elderly patients. (2) Aim: To evaluate whether the sensitivity of intraepithelial lymphocyte cytometric patterns for coeliac disease diagnosis changes with advanced age. (3) Methods: We performed a multicentre study including 127 coeliac disease patients ≥ 50 years: 87 with baseline cytometry (45 aged 50–59 years; 23 aged 60–69 years; 19 aged ≥ 70 years), 16 also with a follow-up cytometry (on a gluten-free diet); and 40 with only follow-up cytometry. (4) Results: In Marsh 3 patients, a sensitivity of 94.7%, 88.9% and 86.7% was observed for each age group using a cut-off value of TCRγδ+ >10% (p = 0.27); and a sensitivity of 84.2%, 83.4% and 53.3% for a cut-off value >14% (p = 0.02; 50–69 vs. ≥70 years), with difference between applying a cut-off of 10% or 14% (p = 0.008). The TCRγδ+ count in the ≥70 years group was lower than in the other groups (p = 0.014). (5) Conclusion: In coeliac patients ≥ 70 years, the TCRγδ+ count decreases and the cut-off point of >10% is more accurate than >14%.

Long-Term Effect of a Gluten-Free Diet on Diarrhoea- or Bloating-Predominant Functional Bowel Disease: Role of the 'Low-Grade Coeliac Score' and the 'Coeliac Lymphogram' in the Response Rate to the Diet

1.

BACKGROUND

The long-term effect of a gluten-free diet (GFD) on functional bowel disorders (FBDs) has been scarcely studied. The aim was to assess the effect of a GFD on FBD patients, and to assess the role of both the low-grade coeliac score and coeliac lymphogram in the probability of response to a GFD. 2.

METHODS

116 adult patients with either predominant diarrhoea or abdominal bloating, fulfilling Rome IV criteria of FBD, were treated with a GFD. Duodenum biopsies were performed for both pathology studies and intraepithelial lymphocyte subpopulation patterns. Coeliac lymphogram was defined as an increase in TCRγδ+ cells plus a decrease in CD3- cells. A low-grade coeliac score >10 was considered positive. 3.

RESULTS

Sustained response to GFD was observed in 72 patients (62%) after a median of 21 months of follow-up, who presented more often with coeliac lymphogram (37.5 vs. 11.4%; p = 0.02) and a score >10 (32 vs. 11.4%; p = 0.027) compared to non-responders. The frequency of low-grade coeliac enteropathy was 19.8%. 4.

CONCLUSION

A GFD is effective in the long-term treatment of patients with previously unexplained chronic watery diarrhoea- or bloating-predominant symptoms fulfilling the criteria of FBD. The response rate was much higher in the subgroup of patients defined by the presence of both a positive low-grade coeliac score and coeliac lymphogram.

Diagnosis of coeliac disease by flow cytometry of intraepithelial lymphocytes: a new 'gold' standard?

OBJECTIVE

The analysis of intraepithelial lymphocytes (IELs) by flow cytometry of duodenal biopsies-the 'IEL' lymphogram-has been proposed as a diagnostic test for coeliac disease. However, its clinical applicability has been limited due to variability in methods and definitions. This study set out to define useful parameters for the application of the IEL lymphogram to the diagnosis of coeliac disease.

DESIGN

Flow cytometry was performed on 117 sets of duodenal biopsies in 107 adult patients with active coeliac disease, long-term coeliac disease on a gluten free diet and a control group. The initial 95 samples were used for hypothesis generation for the subsequent samples comprising 12 patients with coeliac disease and 10 controls.

RESULTS

Rather than using single linear cut-offs for CD3 and T-cell receptor γδ (TCRγδ)+ve IELs, a discriminant function was identified as %CD3+ve IELs+2x(%TCRγδ+IELs)>100. This differentiated coeliac disease from control biopsies in the hypothesis generating group. These results were replicated in the validation group and found to be independent of histology in patients on long-term gluten free diet up to 12 years (combined sensitivity, 98.5%; specificity, 97.7%).

CONCLUSIONS

Flow cytometric analysis of IELs is a highly sensitive and specific adjunct to serology and histological examination for the diagnosis of coeliac disease, even in individuals with coeliac disease following a gluten free diet who exhibit normal duodenal histology.

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.

Minimal Lesions of the Small Intestinal Mucosa: More than Morphology

Minimal lesions of the small bowel are mucosal changes characterized by an increased number of intraepithelial lymphocytes (with or without crypt hyperplasia) and normal villous architecture. Such changes are associated with a wide spectrum of conditions, ranging from food intolerances to infections, and from drugs to immune diseases, with different clinical profiles and manifestations, which complicates the formulation of a differential diagnosis. Patient history, symptom evaluation, and histopathology are the diagnostic features needed to establish a correct diagnosis. Physicians should assist pathologists in formulating a precise morphological evaluation by taking well-oriented small intestinal biopsies and collecting informative clinical findings that inform histopathology. In this current clinical controversy, the authors provide the reader with an appraisal of the small intestine minimal lesions through a careful analysis of the major conditions (e.g., celiac disease and other non-celiac disorders) responsible for such changes and their differential diagnosis. Also, we acknowledge that some of the diseases detailed in this article may progress from an early minimal lesion to overt mucosal atrophy. Thus, the timing of the diagnosis is of paramount importance.

Gamma delta+ intraepithelial lymphocytes and coeliac lymphogram in a diagnostic approach to coeliac disease in patients with seronegative villous atrophy

BACKGROUND

The causes of seronegative villous atrophy can be grouped as coeliac or noncoeliac related. There is no consensus on how to approach subjects with seronegative coeliac disease.

AIM

To evaluate the accuracy of both an increase in CD3⁺ T-cell receptor gamma delta⁺ (TCRγδ⁺ ) intraepithelial lymphocytes and coeliac lymphogram for the diagnosis of coeliac disease in patients with seronegative villous atrophy.

METHODS

Sixty-seven consecutive patients with seronegative villous atrophy were included. Duodenal biopsies to assess TCRγδ⁺ and CD3^- by flow cytometry were performed at the index endoscopy. Coeliac lymphogram was defined as an increase in TCRγδ⁺ plus a decrease in CD3^- intraepithelial lymphocytes. Sensitivity, specificity and Fagan's nomogram were calculated.

RESULTS

Coeliac disease was diagnosed in 37 patients and noncoeliac villous atrophy in 30. Coeliac patients were younger (39 ± 3 vs 55 ± 3 years; P = 0.001), more often showed HLA-DQ2/8 (97.6% vs 61%; P = 0.002) and had a more severe histology (61% vs 32% Marsh 3b-c; P = 0.055), as compared to noncoeliac ones. Coeliac lymphogram was associated with a sensitivity of 87% (CI, 73.7-95) and specificity of 96.7% (82.7-99.9), whereas evaluating only TCRγδ⁺ yielded a sensitivity of 91.3% (79.2-97.6) and specificity of 83.3% (65.3-94.3). Among patients with a pre-test coeliac disease probability of 30%, post-test probabilities were 92% and 5% for positive and negative coeliac lymphogram, and 70% and 4% for positive and negative TCRγδ⁺ .

CONCLUSIONS

Coeliac lymphogram was associated with a high level of diagnostic evidence either against or in favour of coeliac disease in patients with seronegative villous atrophy.

The Neuropathology of Gluten-Related Neurological Disorders: A Systematic Review

Gluten-related neurological disorders (GRND) represent a spectrum of neurological manifestations that are triggered by gluten. In coeliac disease, a T-cell mediated enteropathy is triggered by gluten in genetically predisposed individuals. The underlying pathological mechanism of the neurological dysfunction is not yet clear. The aim of this review is to collate existing neuropathological findings in GRND as a means of aiding the understanding of the pathophysiology. A systematic search of the Pubmed Database yielded 188 articles, of which 32 were included, containing 98 eligible cases with a description of pathological findings in GRND. In gluten ataxia, loss of Purkinje cells, atrophy, gliosis and astrocytosis were apparent, as well as diffuse lymphocytic infiltration and perivascular cuffing with lymphocytes. In patients with large-fiber neuropathy, nerve biopsies revealed axonopathy, loss of myelinated fibers and focal and perivascular infiltration by inflammatory cells. Inflammatory infiltrate was also observed in muscle in myopathy and in cerebrum of patients with encephalopathy and patients with epilepsy. Such changes were not seen in skin biopsies from patients with small fiber neuropathies. The findings from this systematic review suggest an immune mediated pathogenesis for GRND. Future research should focus on the characterization of the inflammatory cell infiltrates and identifying target epitopes.