Intraepithelial T-cell Research Articles

How many cell types form the epithelial lining of the human uterine tubes? Revision of the histological nomenclature of the human tubal epithelium

IntroductionMany widely used international histological textbooks claim that the epithelium of the human uterine tube consists of two, three, and, eventually, four types of cells. Most discrepancies among these textbooks relate to debates regarding the presence or absence of basal cells, whether the peg/intercalary cells and secretory cells are the same or distinct cell populations, and if the epithelium contains a population of immunologically active cells (T- and B-lymphocytes, NK cells, macrophages and dendritic cells) or dispersed endocrine cells. MethodsUterine tubes were obtained from 22 women (average age: 46.73 y) undergoing gynecological surgery. The women were in fertile age, mostly in the middle of the menstrual cycle (ovulation phase). Tissue samples were processed for immunohistochemistry using primary antibodies against proliferation markers (Ki67 and PCNA), immune system cells (CD1a, CD3, CD4, CD8, CD20, CD45RO, CD56, CD68, granzyme B and S100) and disperse endocrine cells (chromogranin A and synaptophysin). ResultsMost of the mature tubal epithelial cells, ciliated cells, and secretory cells were mitotically active (PCNA+), a population of basal undifferentiated cells was not identified. The dividing cells had a narrow-shaped nucleus (Ki67 positive). These cells were morphologically identical to – by the terminology mentioned – intercalary cells, assuming they represented actually dividing cells (epitheliocytus tubarius mitoticus). The tubal “basal cells” displayed small, hyperchromatic nuclei and very pale cytoplasm (clear cytoplasmic halo). They were located in the epithelium adjacent to the basement membrane, were non-mitotically active and their immunophenotype corresponded to intraepithelial regulatory T-lymphocytes (CD3+, CD8+, CD45RO+, CD4−, CD20−, CD56− and granzyme B−). Intraepithelial B-lymphocytes were only rarely identified. Intraepithelial NK cells, dendritic cells, macrophages and dispersed endocrine cells were not identified. ConclusionsWe recommend replacing the term “epitheliocytus tubarius basalis” in the Terminologia Histologica with the term “lymphocytus T intraepithelialis tubarius”, which represents intraepithelial regulatory T-cells (CD8+, CD45RO+) of the uterine tube. Additionally, we propose that intercalary/peg cells are actively dividing cells, instead of effete or degenerating cells. Finally, the histological nomenclature should be corrected in a way that peg/intercalary cells are not considered synonymous terms for secretory cells.

Gut T Cells Feast on GLP-1 to Modulate Cardiometabolic Disease

Glucagon-like peptide-1 (GLP-1) is an enteroendocrine hormone that controls insulin secretion, intestinal function, and food intake. Recently in Nature, He etal. (2019) reported that gut intraepithelial Tcells regulate GLP-1 bioavailability by capturing it on GLP-1 receptors and impacting L-cell numbers. This study delineates a novel endocrine-immune axis through which intestinal immune cells regulate whole-body metabolism.

A Subset of CCL25-Induced Gut-Homing T Cells Affects Intestinal Immunity to Infection and Cancer.

Protective immunity relies upon differentiation of T cells into the appropriate subtype required to clear infections and efficient effector T cell localization to antigen-rich tissue. Recent studies have highlighted the role played by subpopulations of tissue-resident memory (TRM) T lymphocytes in the protection from invading pathogens. The intestinal mucosa and associated lymphoid tissue are densely populated by a variety of resident lymphocyte populations, including αβ and γδ CD8+ intraepithelial T lymphocytes (IELs) and CD4+ T cells. While the development of intestinal γδ CD8+ IELs has been extensively investigated, the origin and function of intestinal CD4+ T cells have not been clarified. We report that CCR9 signals delivered during naïve T cell priming promote the differentiation of a population of IFN-γ-producing memory CD4+ T cells, which displays a TRM molecular signature, preferentially localizes to the gastrointestinal (GI) tract and associated lymphoid tissue and cannot be mobilized by remote antigenic challenge. We further show that this population shapes the immune microenvironment of GI tissue, thus affecting effector immunity in infection and cancer.

Clinical Insignficance of Monoclonal T-Cell Populations and Duodenal Intraepithelial T-Cell Phenotypes in Celiac and Nonceliac Patients.

Refractory celiac disease (RCD) is a rare condition, usually managed at specialized centers. However, gastroenterologists and pathologists in general practices are often the first to consider a diagnosis of RCD in celiac patients with persistent symptoms. The distinction between type I and type II RCD is crucial as patients with RCD II have a shortened life expectancy. The diagnosis of RCD II requires the demonstration of abnormal intraepithelial lymphocytes and/or monoclonal T-cell populations in duodenal biopsies, typically assessed in formalin-fixed paraffin-embedded tissue. We investigated the clinical significance of T-cell receptor gene rearrangements and CD3/CD8 staining in formalin-fixed paraffin-embedded biopsies from 32 patients with RCD I (4), RCD II (3), newly diagnosed celiac disease (CD) (10), established CD patients with follow-up biopsies (10), and Helicobacter pylori-associated lymphocytosis (5). Clonal T-cell populations were present in all lymphocytosis groups but not in normal controls. No difference in the frequency of clonal populations or persistence of identical clones was found between RCD I and II patients. The degree of villous blunting did not correlate with clonal status in any group. No difference in the number of CD3/CD8-positive intraepithelial lymphocytes per 100 enterocytes was found between groups. We suggest that clonal evaluation of T cells should not be employed routinely in the evaluation of CD patients with persistent symptoms until common causes of "apparent refractoriness" have been excluded. In addition, lymphocyte phenotyping and T-cell clonal analysis appear to be insufficient as stand-alone tests to reliably distinguish RCD I and II.

A Case of Incidentally Found CD3+ Lymphocytic Infiltration at Ileocecal Valve During Colonoscopy - Why Should This Be Concerning?

We present an unusual finding of CD 3+ granulomatous patch located within the Ileocecal valve (IC), in an asymptomatic patient. Intestinal intraepithelial lymphocytes (IELs) belong to a unique T-cell population interspersed between epithelial cells of both the small and large intestine. Increased IEL in bowel is associated with lymphocytic colitis, celiac disease, enteropathy associated T cell lymphoma (EATL) or Indolent T cell lymphoproliferative disease. Guidelines for endoscopic investigation of the small intestine are well defined for diagnosis of celiac disease, however there is no indication for colonic investigation, which could leave IEL's, EATL's or isolated celiac disease undetected within the colon. A 47 year old African male with history of hypertension, schizophrenia, was seen in clinic and scheduled a screening colonoscopy. He denied nausea, vomiting, abdominal pain, loss of appetite, unintentional weight loss, hematemesis, melena or hematochezia and reported regular bowel movements. He had no family history of GI malignancy. His physical exam was unremarkable. Colonoscopy revealed areas of erythema at the ileocecal valve. Pathology from biopsies showed polypoid fragments of non-dysplastic colonic mucosa with dilated ectatic lymphatics and mucosal edema. Additionally, mucosal lymphoid aggregates with a mild increase in intraepithelial CD3-positive T-cells and CD 3+ granulomatous patch within the Ileocecal valve (IC) were present. Further studies revealed; TTG 11 (0-5U/mL), Gliadin IGA 47 (>30 strong positive), Endomysial antibody IGA negative, B12 levels- 284 (low normal) and HIV negative. An upper endoscopy performed showed normal gastric and duodenal mucosa, with duodenal biopsies showing normal intraepithelial lymphocytes without villous atrophy. Oncology was consulted for increased GI mucosal CD-3 cells, likely non-specific but concerning for cryptic/ intermediate enteropathy-type intestinal T cell lymphoma(EITCL) with impression that the biopsy revealed solely incidentally reactive T cell infiltrates. In our patient, the CD3-positive T-cells and CD 3+ granulomatous patch at Ileocecal valve (IC) with positive Celiac serological studies established the diagnosis of subclinical celiac. This is of potential importance for four reasons: the danger of malignancy, the presence of unsuspected nutritional deficiencies, the association with low-birth weight infants in affected mothers, and the occurrence of autoimmune disorders.

Non-canonicaly recruited TCR\u03b1\u03b2CD8\u03b1\u03b1 IELs recognize microbial antigens

In the gut, various subsets of intraepithelial T cells (IELs) respond to self or non-self-antigens derived from the body, diet, commensal and pathogenic microbiota. Dominant subset of IELs in the small intestine are TCRαβCD8αα+ cells, which are derived from immature thymocytes that express self-reactive TCRs. Although most of TCRαβCD8αα+ IELs are thymus-derived, their repertoire adapts to microbial flora. Here, using high throughput TCR sequencing we examined how clonal diversity of TCRαβCD8αα+ IELs changes upon exposure to commensal-derived antigens. We found that fraction of CD8αα+ IELs and CD4+ T cells express identical αβTCRs and this overlap raised parallel to a surge in the diversity of microbial flora. We also found that an opportunistic pathogen (Staphylococcus aureus) isolated from mouse small intestine specifically activated CD8αα+ IELs and CD4+ derived T cell hybridomas suggesting that some of TCRαβCD8αα+ clones with microbial specificities have extrathymic origin. We also report that CD8ααCD4+ IELs and Foxp3CD4+ T cells from the small intestine shared many αβTCRs, regardless whether the later subset was isolated from Foxp3CNS1 sufficient or Foxp3CNS1 deficient mice that lacks peripherally-derived Tregs. Overall, our results imply that repertoire of TCRαβCD8αα+ in small intestine expends in situ in response to changes in microbial flora.

Abstract 4669: Role of CD8+ tissue-resident memory T (TRM) cells in anti-tumor T-cell response and cancer immunotherapy

Abstract Tissue-resident memory T (TRM) cells, very often defined by the expression of CD103 integrin, correspond to a new subset of long-lived memory T lymphocytes that reside in tissues and are highly protective during localized reinfections. CD8+ TRM cells also frequently reside in human epithelial tumors and play an essential role in anti-tumor T-cell responses. In this context, our previous results indicated that the interaction of CD103 integrin with its ligand, the epithelial cell marker E-cadherin, favors adhesion of TRM cells to their specific epithelial cancer cells and participate to the potentiation of T-cell receptor (TCR)-mediated cytotoxic activity and cytokine production. We also demonstrated that an enhanced CD103+ tumor-infiltrating lymphocytes (TIL) subset correlates with improved early-stage non-small cell lung carcinoma (NSCLC) patient survival and increased intraepithelial T-lymphocyte infiltration. Notably, TRM cells are enriched with tumor-specific T cells and express high levels of inhibitory receptors, including PD-1 and Tim-3, making them an attractive target for cancer immunotherapy, such as checkpoint blockade. Moreover, we provided evidence that CD103 is involved in T-cell recruitment within epithelial tumor islets and in local early T-cell signaling. Our more recent results indicated that integrin-linked kinase (ILK) and paxillin adaptor protein are directly involved in CD103 bidirectional signaling events and defined the CD103 cytoplasmic domain that controls TRM adhesion, migratory behavior and TCR-mediated T-cell functions. Data emphasizing the contribution of CD8+/CD103+ TRM cells in promoting intra-tumoral cytotoxic T lymphocyte (CTL) responses and in success of cancer immunotherapy will be discussed. Citation Format: Fathia Mami-Chouaib. Role of CD8+ tissue-resident memory T (TRM) cells in anti-tumor T-cell response and cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4669.

Expression of α-Defensins, CD20+ B-lymphocytes, and Intraepithelial CD3+ T-lymphocytes in the Intestinal Mucosa of Patients with Liver Cirrhosis: Emerging Mediators of Intestinal Barrier Function.

The present study investigates the role of innate and adaptive immune system of intestinal mucosal barrier function in cirrhosis. Forty patients with decompensated (n = 40, group A), 27 with compensated cirrhosis (n = 27, group B), and 27 controls (n = 27, group C) were subjected to duodenal biopsy. Expression of α-defensins 5 and 6 at the intestinal crypts was evaluated by immunohistochemistry and immunofluorescence. Serum endotoxin, intestinal T-intraepithelial, and lamina propria B-lymphocytes were quantified. Cirrhotic patients presented higher endotoxin concentrations (p < 0.0001) and diminished HD5 and HD6 expression compared to healthy controls (p = 0.000287, p = 0.000314, respectively). The diminished HD5 and HD6 expressions were also apparent among the decompensated patients compared to compensated group (p = 0.025, p = 0.041, respectively). HD5 and HD6 expressions were correlated with endotoxin levels (r = -0.790, p < 0.0001, r = - 0.777, p < 0.0001, respectively). Although intraepithelial T-lymphocytes were decreased in group A compared to group C (p = 0.002), no notable alterations between groups B and C were observed. The B-lymphocytic infiltrate did not differ among the investigated groups. These data demonstrate that decreased expression of antimicrobial peptides may be considered as a potential pathophysiological mechanism of intestinal barrier dysfunction in liver cirrhosis, while remodeling of gut-associated lymphoid tissue as an acquired immune response to bio-pathogens remains an open field to illuminate.

Developing a diagnostic understanding of GERD phenotypes through the analysis of levels of mucosal injury, immune activation, and psychological comorbidity.

SummaryPatients with gastroesophageal reflux disease (GERD) can present with typical or atypical symptoms. The aim of this study is to explore the underlying physiological and psychological mechanisms that lead to different symptomatic manifestations of GERD. A total of 238 patients diagnosed with GERD underwent gastroscopy, 24 h multichannel intraluminal impedance-pH (MII-pH) monitoring, and psychological assessment with questionnaires. Patient symptoms were used to classify GERD into phenotypes of typical reflux syndrome (TRS, n = 87), reflux chest pain syndrome (RCS, n = 98), and extraesophageal syndromes (EES, n = 53). 38 healthy volunteers served as controls. Reflux parameters and baseline impedance values (BIVs) were acquired from MII-pH monitoring results. A subset of subjects were biopsied from the lower esophagus; certain immune cells were stained with immunohistochemistry. BIVs in GERD patients (TRS, RCS, and EES) were significantly lower than in healthy controls and TRS patients exhibited the lowest BIVs (all P < 0.01). This indicated that the extent of mucosal injury differed across groups. TRS patients had higher acid exposure time (AET) compared to RCS, EES and controls (all P < 0.05). RCS patients had more intraepithelial T lymphocyte (IEL) and mast cell (MC) infiltration, and higher psychometric scores compared to TRS patients and controls (all P < 0.05), suggesting a possible stress-related esophageal hypersensitivity basis. TRS patients are characterized by acid reflux and correlated mucosal injury, which explains their typical reflux symptoms. RCS patients exhibit less acid-related injury but possible psychological stress-related esophageal hypersensitivity, which could be the main cause of their esophageal pain.

Back cover story: Eur. J. Immunol. 1'18

European Journal of ImmunologyVolume 48, Issue 1 Back CoverFree Access Back cover story: Eur. J. Immunol. 1'18 First published: 10 January 2018 https://doi.org/10.1002/eji.201870018AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Our back cover features the immunohistology of a lung from a C57BL/6 mouse re-challenged with influenza A virus (IAV). In the center panel, the juxtaposition of lung epithelial cells (stained with anti-E-cadherin, red) and inflammatory cells (anti-CD103, green), including migrating DCs and intraepithelial T-cells, is displayed in addition to nuclear staining (blue). The image is taken from Yoshizawa et al. (pp. 128–150), where the authors show that airway epithelia and adjacent lamina propria locales, not iBALT, represent microenvironments for tissue resident memory T-cell generation. Transcriptional profiling reveals differences in activation, attenuation and adhesion pathways amongst polyclonal resident effector and memory T-cells based on an TCR-pMHC encounter involving two immunodominant IAV epitopes. Volume48, Issue1January 2018 RelatedInformation

Alterations of Serum Lipid Profile Patterns in Oral Lichen Planus Patients: A Case-Control Study.

Background:Oral lichen planus (OLP) is a chronic disease of established immune-mediated pathogenesis. It most commonly, protractedly, and persistently involves the mucosa of the oral cavity. Antigen-specific and nonspecific mechanisms play a role in its pathogenesis, leading to T-cell accumulation in superficial lamina propria, intraepithelial T-cell migration, and keratinocyte apoptosis in OLP. Previous studies have indicated the possibility of serum lipid derangement in chronic inflammatory diseases such as systemic lupus erythematosus and psoriasis, which in turn results in elevated cardiovascular disease risk. Inflammation causes disturbances in lipid metabolism such as decrease in high-density lipoprotein-cholesterol (HDL-C) and increase in very low-density lipoprotein (VLDL)-cholesterol and hypertriglyceridemia due to direct effect on T-cell responses. Prolonged dyslipidemia, due to chronic inflammatory condition, enhances the formation of atherosclerotic plaques and thereby augments the risk of cardiovascular disease in such patients. With this background, a possible correlation between OLP and serum lipid level derangement can be anticipated. Hence, this study was taken up to probe into an association between the two.Aims:To determine and compare the serum lipid levels in OLP patients and healthy controls, to inquire into the possible association of OLP with alterations in serum lipid profile patterns, and to determine if the clinical characteristics of OLP differed with alterations in serum lipid profile patterns.Subjects and Methods:Sixty patients comprising 30 cases and 30 controls were enrolled for the study. Thirty cases of clinically and pathologically diagnosed OLP and 30 age- and sex-matched controls were subjected to blood examination for the assessment of serum lipid level, i.e., HDL, LDL, VLDL, and triglyceride. The obtained data were compared with standard values to assess any alterations of the serum lipid levels.Statistical Analysis Used:Cramer's V-test was performed for all the tests to measure association between two nominal variables. A P ≤ 0.05 was considered statistically significant.Results:Dyslipidemia was observed in 13 (46.67%) cases as against 7 (23.33%) controls. Thus, a significant number of cases were found to have an associated serum dyslipidemia. However, pertaining to individual serum lipid levels in cases and controls, the association was found to be statistically insignificant.Conclusions:The current study suggested an evident association between dyslipidemia and OLP. We recommend imminent studies on a larger population to additionally substantiate a positive association between the two.

What we know about the cellular microenvironment of clinically healthy human gingiva? An immunohistochemical and histological study

AbstractThe present study deals with histological descriptions of clinically healthy human gingivae through the methods of light, electron microscopy and immunohistochemistry. Even clinically healthy human gingivae are subject to constant bacterial and mechanical influences present in the oral cavity; therefore, the term “normal gingiva” is misleading. The aim of this study was to identify, in clinically healthy gingiva, all active cells through immunohistochemical markers and light and electron microscope examination. In tissue samples from clinically healthy gingivae of nine patients, we observed the presence of different cells (e.g., T- and B-lymphocytes, macrophages, Merkel cells, Langerhans cells, proliferating cells) and some components of their extracellular matrix that use antibodies against S-100 protein, CD68, CD20, CD45RO, CD20, and Ki67. The presence of immunologically active cells and the ultrastructural characteristics of gingivae were also confirmed. The stratified squamous epithelium of human gingiva contains a population of Langerhans cells and intraepithelial Tlymphocytes. The underlying dense connective tissue contains primarily fibroblasts, but also T-lymphocytes, occasionally B-lymphocytes, plasma cells, and macrophages can be seen. As a border between the oral cavity and the internal environment of the human body, the gingivae are an important part of the immune system. Such findings show that, in healthy gingival tissue, there are constantly ongoing anti-inflammatory, immunological, and regenerative reactions and processes.

Location matters for immunosuppression

Mucosal Immunology In the gut, food antigens and resident microbes can trigger unwanted immune responses. Immunosuppressive cell types in the gut, such as regulatory T cells (Tregs) and intraepithelial T lymphocytes (IELs), help to keep these responses at bay. Sujino et al. report that the specific anatomical location within the gut shapes the properties of the suppressive T cell populations that reside there (see the Perspective by Colonna and Cervantes-Barragan). Using mice, they find that Tregs primarily reside in the lamina propria. Tregs migrate to the intestinal epithelium, where they convert to IELs in a process that depends on the microbiota and the loss of a specific transcription factor. Tregs and IELs also play distinct but complementary roles in suppressing intestinal inflammation. Science , this issue p. [1581][1]; see also p. [1515][2] [1]: /lookup/doi/10.1126/science.aaf3892 [2]: /lookup/doi/10.1126/science.aag1719

Tissue adaptation of regulatory and intraepithelial CD4⁺ T cells controls gut inflammation.

Foxp3(+) regulatory T cells in peripheral tissues (pT(regs)) are instrumental in limiting inflammatory responses to nonself antigens. Within the intestine, pT(regs) are located primarily in the lamina propria, whereas intraepithelial CD4(+) T cells (CD4(IELs)), which also exhibit anti-inflammatory properties and depend on similar environmental cues, reside in the epithelium. Using intravital microscopy, we show distinct cell dynamics of intestinal T(regs) and CD4(IELs) Upon migration to the epithelium, T(regs) lose Foxp3 and convert to CD4(IELs) in a microbiota-dependent manner, an effect attributed to the loss of the transcription factor ThPOK. Finally, we demonstrate that pT(regs) and CD4(IELs) perform complementary roles in the regulation of intestinal inflammation. These results reveal intratissue specialization of anti-inflammatory T cells shaped by discrete niches of the intestine.

Gut intraepithelial myelin reactive CD4+T cells suppress central nervous system autoimmunity via LAG3

Abstract Objective Multiple sclerosis (MS) is an autoimmune disease that targets the myelin of the central nervous system (CNS). Increasing incidence of MS in Japan let us question which components of the immune system are altered by environmental factors. Gut mucosa is by far the largest immune organ that interacts with the external environment. Since T cells are pivotal in controlling CNS inflammation, we investigated the existence of myelin reactive T cells that might be induced in the gut and their influence on CNS autoimmunity. Methods Gut-T cells from MOG(35–55) specific T cell receptor transgenic (2D2) mice were analyzed by FACS. Sorted gut-T cells were adoptively transferred to experimental autoimmune encephalomyelitis (EAE) induced by immunization with MOG(35–55). Blocking antibodies were used for functional analysis. Gut microbiota was modulated by oral antibiotics treatment. Diets including poor or rich aryl hydrocarbon receptor ligands (AHRL) were fed to mice. Results Here we demonstrate that the gut epithelium of 2D2 mice is inhabited by intraepithelial T-lymphocytes (IEL) that can inhibit EAE upon transfer. The regulatory IEL had the phenotype of CD4+‘induced’IEL (CD2+CD5+), exhibited TH17-like profile and had ability to infiltrate the inflamed CNS tissue. The IEL constitutively expressed Ctla4 and Tgfb1, and markedly upregulated Lag3 in the CNS, thereby inhibiting the inflammation. We also demonstrated that the IEL are induced by gut microbiota and AHRL. Conclusions Gut environment favors the generation of myelin reactive T cells that have unique regulatory function. Dysbiosis or poor AHRL in diet may reduce the induction of such regulatory cells, thus promoting the development of MS.

CD103 defines intraepithelial CD8+ PD1+ tumour-infiltrating lymphocytes of prognostic significance in endometrial adenocarcinoma

IntroductionIntraepithelial CD8+ tumour-infiltrating T-lymphocytes (TIL) are associated with a prolonged survival in endometrial cancer (EC). By contrast, stromal infiltration of CD8+ TIL does not confer prognostic benefit. A single marker to discriminate these populations would therefore be of interest for rapid assessment of the tumour immune contexture, ex vivo analysis of intraepithelial and stromal T-cells on a functional level and/or adoptive T-cell transfer. Here we determined whether CD103, the αE subunit of the αEβ7integrin, can be used to specifically discriminate the epithelial and stromal CD8+ TIL populations in EC. MethodsCD103+ TIL were quantified in a cohort of 305 EC patients by immunohistochemistry. Localization of CD103+ cells and co-expression of CD103 with CD3, CD8, CD16 and FoxP3 were assessed by immunofluorescence. Further phenotyping of CD103+ cells was performed by flow cytometry on primary endometrial tumour digests. ResultsCD8+CD103+ cells were preferentially located in endometrial tumour epithelium, whereas CD8+CD103− cells were located in stroma. CD103+ lymphocytes were predominantly CD3+CD8+ T-cells and expressed PD1. The presence of a high CD103+ cell infiltration was associated with an improved prognosis in patients with endometrial adenocarcinoma (p = 0.035). Moreover, this beneficial effect was particularly evident in high-risk adenocarcinoma patients (p = 0.031). ConclusionsBecause of the restricted expression on intraepithelial CD8+ T-cells, CD103 may be a suitable biomarker for rapid assessment of immune infiltration of epithelial cancers. Furthermore, this intraepithelial tumour-reactive subset might be an interesting T-cell subset for adoptive T-cell transfer and/or target for checkpoint inhibition therapy.

Abstract B075: CD103 integrin promotes T-cell recruitment and activation within epithelial tumors

Abstract Cancer immunotherapies specifically target tumors by optimizing the capacity of host cytotoxic T lymphocytes (CTL) to recognize and kill malignant cells. To destroy their target, CTL must migrate to the tumor, infiltrate the stroma and then interact with cancer cells. Recruitment of T lymphocytes within the tumor involves several sequential steps regulated by molecular interactions with a variety of stromal cell types and coordinated by chemotactic agents, extracellular matrix proteins and cell surface adhesion molecules. Integrins are one of the major families of adhesion molecules that contribute to lymphocyte development, migration, extravasation and activation. CD103 integrin and its ligand, the epithelial cell marker E-cadherin, play a crucial role in promoting both tumor cell cytotoxicity and cytokine secretion. Accumulating evidence also indicates that CD103 on CD8+ tumor-infiltrating lymphocytes (TIL) is associated with increased intraepithelial T-cell infiltration and that an enhanced CD103+ TIL subset correlates with improved patient survival in several cancers. However, the contribution of CD103 to promoting T-cell recruitment within epithelial tumor regions, and the influence of TGF-beta, abundant within the tumor microenvironment, on integrin functions and signaling remain poorly understood. In the present study we provide evidence that CD103 is directly involved in T-cell recruitment within epithelial tumor islets and in local early T-cell signaling. Moreover, TGF-beta triggers integrin-mediated functional activities by promoting phosphorylation of integrin-linked kinase (ILK) and its subsequent binding to CD103, thus initiating an “inside-out” signaling leading to activation and clustering of the integrin and thereby initiating an “outside-in” signal that contributes to T-cell stimulation, spreading and cytotoxicity. We conclude that TGF-beta, while known for its protumoral effects, promotes an antitumor CTL response by activating CD103 integrin. Citation Format: Marie Boutet, Jr., Fathia Mami-Chouaib, Sr. CD103 integrin promotes T-cell recruitment and activation within epithelial tumors. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B075.

The contribution of intraepithelial inflammatory cells to the histological diagnosis of microscopic esophagitis

Diagnosis of gastro-esophageal reflux disease (GERD) is mainly based on symptom evaluation, possibly coupled with various invasive investigations (endoscopy, pH-metry, and impedance). New input has recently come from histology: in this context, the diagnostic role of inflammatory cells other than eosinophils and neutrophils is still debated. Aim of the study is to evaluate the diagnostic relevance of intraepithelial lymphocytes, mast cells, and Langerhans cells in GERD-associated microscopic esophagitis (GAME). Twenty healthy volunteers and 119 patients with GERD symptoms were prospectively recruited and subdivided, on the basis of endoscopy and pH-metry, in erosive (ERD, 48) and non-erosive disease (NERD, 71). Biopsy samples at 2 cm above the Z-line and at Z-line were evaluated for GERD-associated histological lesions (basal cell hyperplasia, papillae elongation, intercellular space dilatation, intraepithelial eosinophils, and neutrophils). Immunohistochemistry for T lymphocytes (CD3, CD4, CD8), B lymphocytes (CD20), NK cells (CD56), macrophages (CD68), mast cells (c-Kit), and Langerhans cells (S100) was performed. Among inflammatory cells, only intraepithelial T lymphocytes (ITLs) showed statistical correlation with the other histological lesions both in ERD and NERD. ITLs distinguished GERD patients from controls with good sensitivity and specificity (85.5 and 85 % at 2 cm above Z-line; 89.5 and 75 % at Z-line) when a cut-off of 20 cells was applied. An analysis of the T subpopulations found a CD4+/CD8+ ratio close to 1:1; B cells, mast cells, Langerhans cells, NK cells, and macrophages showed a limited role in GERD. ITL evaluation represents an additional useful parameter in the histological evaluation of GAME.

Changes in the inflammatory microenvironment in premalignant colonic adenomatous polyps: Evidence for immunosurveillance?

535 Background: The majority of colorectal cancers develop through the adenoma-carcinoma sequence. Recently, the host inflammatory response has become recognized as a key determinant of outcome. In particular, a pronounced peri-tumoral local inflammatory infiltrate identifies those with a better outcome. The present study aimed to characterize the local inflammatory response in pre-malignant colorectal adenomatous polyps. Methods: Patients with adenomatous polyps removed at colonoscopy as part of a population FOBt screening program were identified from a prospectively maintained database. All polyps were greater than 1cm. Whole slide immunohistochemistry was performed to assess intraepithelial T-cell (CD3+), cytotoxic T-cell (CD8+) and macrophage (CD68+) infiltrate. Inter-observer agreement for assessment of inflammatory cell infiltrate was good or better for CD3+, CD8+ and CD68+staining (Kappa 0.66, 0.66, 0.79 respectively). Results: A total of 207 adenomatous polyps, 107 high-grade (HG), 100 low-grade (LG), from 134 patients were included. Median age was 65 years, 33 (25%) were female and 15 (11%) were taking regular aspirin. Comparing HG and LG polyps, there were more older and female patients in the HG group (p&lt;0.05). There was no difference in location (p=0.222), macroscopic morphology (p=0.445) or aspirin (p=0.377) use between groups. Microscopically, HG polyps were more likely to contain a villous component than LG polyps (65% vs 50%, p&lt;0.05). Overall, high levels of CD3+, CD8+ and CD68+ infiltrate were observed in 68%, 25% and 72% of polyps respectively. Both CD3+ (74% vs 61%, p&lt;0.05) and CD8+ (37% vs 13%, p&lt;0.001) infiltrate was higher in HG polyps compared to LG polyps. There was no association with polyp grade and CD68+infiltrate (74% vs 70%, p=0.540). Conclusions: An increase in local T-lymphocytic infiltrate, but not macrophage infiltrate was identified with progression from low-grade to high-grade dysplasia. This would suggest a specific response to early disease progression confirming increased immunosurveillance. Therefore, such early stage disease may amenable to immunomodulatory treatment.

Acute abdomen in a patient with coeliac disease: a case report and literature review of enteropathy-associated T-cell lymphoma (EATl)

A 71-year-old female with a history of poorly-controlled coeliac disease presented with worsening symptoms of small bowel obstruction over 3 weeks. Jejunal, ileal and mesenteric resections were performed. The patient did not recover after surgery and died 3 weeks later. Patchy mucosal ulcerative plaques were seen, corresponding to transmural infiltration by medium-to-large atypical lymphoid cells positive with CD3 and CD56 but negative for CD5, CD8, CD4 and CD20. Similar atypical cells were identified in all regional lymph nodes, in a predominantly sinusoidal distribution. Remaining small bowel mucosa showed typical histological features of coeliac disease, comprising severe villous atrophy, intraepithelial lymphocytosis (reactive lymphocytes) and crypt hyperplasia. EATL of the small intestine with involvement of mesenteric lymph nodes, occurring in the setting of coeliac disease, was diagnosed. EATL is an uncommon lymphoma of intraepithelial T-lymphocytes mostly occurring in patients with coeliac disease. Ten to twenty percent of cases may occur sporadically without coeliac disease (type II EATL) in which monomorphic, medium-sized cells are present. Type II EATL has a distinctive immunophenotype. Both EATL types have very poor prognosis due to low tumour chemosensitivity and aggressive behaviour. Major postsurgical complications are also common in patients who are nutritionally deficient due to coeliac disease.