Pro-inflammatory cytokine expression and the STAT1/3 pathway in canine chronic enteropathy and intestinal T-cell lymphoma

The accumulation of intraepithelial lymphocytes (IELs) is a histopathological feature of canine chronic enteropathy (CE), and IELs are considered the cells of origin of intestinal T-cell lymphoma (ITCL). However, the pathogenic mechanism of IEL activation in CE remains unclear. This study hypothesized that the expression of proinflammatory cytokines, associated with cytotoxic T/NK-cell activation, is upregulated in CE and ITCL, and examined the expression of IFN-γ, IL-2, IL-12p35, IL-12p40, IL-15, and IL-21 and the downstream signal transducers and activators of transcription (STAT) pathway in the duodenal mucosa of dogs without lesions (n = 11; NC), with IEL-CE (n = 19; CE without intraepithelial lymphocytosis), IEL+CE (n = 29; CE with intraepithelial lymphocytosis), and with ITCL (n = 60). Quantitative polymerase chain reaction (PCR) revealed that IFN-γ and IL-21 were higher in IEL+CE than in IEL-CE or NC. Western blot revealed upregulation of STAT1 and STAT3 in IEL+CE. Double-labeling immunohistochemistry revealed a positive correlation between the Ki67 index of CD3+ T-cells and IFN-γ expression levels. Immunohistochemistry revealed a higher ratio of p-STAT1-positive villi in IEL+CE and ITCL than IEL-CE and NC, which positively correlated with IFN-γ expression levels. Among the 60 ITCL cases, neoplastic lymphocytes were immunopositive for p-STAT1 in 28 cases and p-STAT3 in 29 cases. These results suggest that IFN-γ and IL-21 contribute to the pathogenesis of IEL+CE, and IFN-γ may be involved in T-cell activation and mucosal injury in CE. STAT1 and STAT3 activation in ITCL cells suggests a role for the upregulation of the STAT pathway in the pathogenesis of ITCL.

The effect of adding wheat and corn gluten to the diet of rats on the autoimmune and histopathological parameters in the intestine and liver

This study investigated the histopathological and immunohistochemical effect on the intestine and liver tissues with addition of the soybean meal (SBM), wheat Gluten meal (WGM) and Corn gluten meal (CGM) to rat diet. A total of 24 average twenty–day–old male rats (Wistar albino) were used in the study. The rats were randomly divided into 3 groups with 8 animals in each group (Control, Wheat and Corn groups). The diet provided to all three groups contained proteins, which were SBM, WGM and CGM in the Control, Wheat and Corn groups, respectively. In the study, the group fed with SBM was used as the Control group. Rats were fed a diet containing 22% crude protein and 2,598 kcal·kg-1 metabolic energy throughout the experimental period. The feeding trial was continued for a period of 50 days. Degenerative changes of varying severity in intestinal epithelial cells and atrophy in villi were observed. Similarly, the degenerative changes, especially vacuolar or hydropic degeneration were determined in hepatocytes. It was determined that the CD4 level were statistically significantly increased in the Wheat and Corn groups compared to the Control group (P<0.01) on intestine tissue. Also, it was determined that the IgA level was statistically significantly increased of the Wheat and Corn groups in liver tissue. (P<0.05). As a result, it was observed that the histopathological and immunohistochemical parameters of the intestine and liver tissues of the rats fed with diets containing highly WGM and CGM were limitedly affected.

Prognostic value of increased intraepithelial lymphocytes and lymphocytic clonality in dogs with chronic enteropathy or small-cell lymphoma

The clinical significance of severe infiltration of small intraepithelial lymphocytes (IEL) and the results of polymerase chain reaction for antigen receptor rearrangement (PARR) in dogs with chronic enteropathy (CE) and small-cell lymphoma (SCL) are controversial. This cohort study aimed to evaluate the prognostic significance of the IEL and PARR results in dogs with CE or SCL. Although definitive diagnostic histopathological criteria for SCL in dogs have yet to be established, dogs with the histopathological findings of severe IEL infiltration were diagnosed with SCL in this study. One hundred and nineteen dogs were recruited, with 23 dogs classified as having SCL and 96 dogs as having CE. The positive rate of PARR was 59.6 % (71/119) in the duodenum and 57.7 % (64/111) in the ileum. Subsequently, three dogs with SCL and four dogs with CE developed large-cell lymphoma (LCL). The median overall survival (OS) of dogs with SCL was 700 days (range, 6-1410 days), and that of dogs with CE was not reached. In the log-rank test, shorter OS was observed in cases with histopathological SCL (P = 0.035), clonal TCRγ rearrangement in the duodenum (P = 0.012), and clonal IgH rearrangement in the ileum (P < 0.0001). The Cox proportional hazards model adjusted for sex and age showed that histopathological SCL (hazard ratio [HR] 1.74; 95 % confidence interval [CI], 0.83-3.65), duodenal clonal TCRγ rearrangement (HR, 1.80; 95 % CI, 0.86-3.75), and ileal clonal IgH rearrangement (HR, 2.28; 95 % CI, 0.92-5.70) could shorten overall survival, although their 95 % CIs included 1.0. These results indicate that severe IEL infiltration could be a useful histopathological feature for diagnosing SCL, and clonality-positive results could be a negative prognostic factor in dogs with CE. Furthermore, the development of LCL should be carefully monitored in dogs with CE and SCL..

Immunophenotyping of intraepithelial lymphocytes in canine chronic enteropathy and intestinal T-cell lymphoma using endoscopic samples

Human enteropathy-associated T-cell lymphoma (EATL) is considered to be derived from intraepithelial lymphocytes (IELs); however, the origin of canine intestinal T-cell lymphoma (ITCL) remains unclear. Histological, immunohistochemical, and clonality examinations were performed using endoscopically collected canine duodenum samples of mucosal lesions of chronic enteropathy (CE; 73 cases) and ITCL without transmural neoplastic mass lesions (64 cases). Histopathological examinations revealed the intraepithelial accumulation of lymphocytes (called "intraepithelial lymphocytosis") in 54/73 CE cases (74%) and the epitheliotropism of neoplastic lymphocytes in 63/64 ITCL cases (98%). Immunohistochemically, IELs in CE with intraepithelial lymphocytosis (IEL⁺CE) were diffusely immunopositive for CD3, with scattered immunopositivity for CD5, CD8, CD20, and granzyme B (GRB). The percentage of CD8⁺ in CD3⁺ IELs was significantly lower in IEL⁺CE than in CE without intraepithelial lymphocytosis (IEL^-CE). Double-labeling immunohistochemistry revealed a high percentage of GRB expression in CD8^- IEL among IEL⁺CE. Among 64 ITCL cases, CD3 was immunopositive in 64 (100%), CD5 in 22 (34%), CD8 in 8 (13%), CD20 in 12 (19%), CD30 in 13 (20%), and GRB in 49 (77%). In CD3⁺ cells, Ki67 immunopositivity was highest in ITCL, intermediate in IEL⁺CE, and lower in IEL^-CE. A clonal TCR gene rearrangement was detected in 1/19 IEL^-CE cases (5%), 15/54 IEL⁺CE (28%), and 38/58 ITCL (66%). These results indicate that the immunophenotype of canine ITCL (CD8^-GRB⁺) is similar to that of the increased IELs in CE. The high proliferative activity and clonality of T cells in IEL⁺CE suggest that canine ITCL originates from these IELs, similar to human EATL.

Current diagnostics for chronic enteropathies in dogs

Chronic enteropathies (CEs) in dogs describe a group of idiopathic disorders characterized by chronic persistent or recurrent gastrointestinal (GI) signs. Three major subgroups of CE can be identified by their response to treatment: Food-responsive disease (FRD), antibiotic-responsive disease (ARD), and steroid-responsive disease (SRD). The clinical diagnosis of CE is made by exclusion of all other possible causes of chronic diarrhea and includes histologic assessment of intestinal biopsies. The process of diagnosing canine CE can therefore be very time-consuming and expensive, and in most cases, does not help to identify dogs that will respond to a specific treatment. The development of novel diagnostic tests for canine CE has therefore focused on the accuracy of such tests to predict treatment responses. In this article, several novel assays that have the potential to become commercially available will be discussed, such as genetic tests, perinuclear anti-neutrophil cytoplasmic antibodies (pANCA), antibodies against transglutaminase/gliadin, antibodies against E coli OmpC/flagellin, and micro RNAs.

Histopathological features and immunophenotyping of canine transmural gastrointestinal lymphoma using full-thickness biopsy samples

To elucidate the histopathological characteristics and immunophenotypes of canine transmural "mass-forming" gastrointestinal lymphomas and plasmacytomas, 83 surgically resected biopsy samples were examined. All lymphomas and plasmacytomas were located in the small or large intestine except for 1 plasmacytoma which was in the stomach. According to the World Health Organization (WHO) classification, B-cell neoplasms (17 cases) included lymphoplasmacytic lymphoma (6/17), plasmacytoma (5/17), follicular lymphoma (3/17), and diffuse large B-cell lymphoma (3/17). Based on nuclear sizes, T-cell neoplasms (66 cases) were broadly divided into large cell lymphoma (LCL; 48/66) and small cell lymphoma (SCL; 18/66). According to the WHO classification, T-cell neoplasms included anaplastic large T-cell lymphoma (ALCL; 10/66), angiotropic T-cell lymphoma (3/66), mixed inflammatory type peripheral T-cell lymphoma (mixed inflammatory type PTCL; 33/66), and PTCL-not otherwise specified (PTCL-NOS; 20/66). Mixed inflammatory type PTCLs were further divided into histiocyte- (27/33) and eosinophil- (6/33) dominant types. Immunohistochemically, lymphoplasmacytic lymphomas were positive for Pax5 (6/6) and IgM (5/6), while plasmacytomas were positive for IgG (5/6) and negative for Pax5. LCLs were immunopositive for granzyme B in 31/48 cases (65%) and CD8 in 9/48 cases (19%), while SCLs were immunopositive for granzyme B in 3/18 cases (17%) and CD8 in 3/18 cases (17%). Furthermore, 8/10 cases (80%) of ALCL and 19/27 cases (70%) of histiocyte-dominant PTCL were immunopositive for granzyme B, whereas 6/20 cases (30%) of PTCL-NOS, 1/6 cases (17%) of eosinophil-dominant PTCL, and no cases of angiotropic T-cell lymphomas were immunopositive for granzyme B. The present study describes the immunophenotypes in different histological types of transmural gastrointestinal lymphomas in the dog.

Utility of the combined use of 3 serologic markers in the diagnosis and monitoring of chronic enteropathies in dogs

BACKGROUND

Dogs with chronic enteropathies (CE) displayed elevated IgA seropositivity against specific markers that can be used to develop a novel test.

OBJECTIVE

To assess a multivariate test to aid diagnosis of CE in dogs and to monitor treatment-related responses.

ANIMALS

One hundred fifty-seven dogs with CE/inflammatory bowel disease (IBD), 24 dogs non-IBD gastrointestinal disorders, and 33 normal dogs.

METHODS

Prospective, multicenter, clinical study that enrolled dogs with gastrointestinal disorders. Serum sample collected at enrollment and up to 3 months follow-up measuring OmpC (ACA), canine calprotectin (ACNA), and gliadin-derived peptides (AGA) by ELISA.

RESULTS

Seropositivity was higher in CE/IBD than normal dogs (66% vs 9% for ACA; 55% vs 15% for ACNA; and 75% vs 6% for AGA; P < .001). When comparing CE/IBD with non-IBD disease, ACA and ACNA displayed discriminating properties (66%, 55% vs 12.5%, 29% respectively) while AGA separated CE from normal cohorts (54% vs 6%). A 3-marker algorithm at cutoff of ACA > 15, ACNA > 6, AGA > 60 differentiates CE/IBD and normal dogs with 90% sensitivity and 96% specificity; and CE/IBD and non-IBD dogs with 80% sensitivity and 86% specificity. Titers decreased after treatment (47%-99% in ACA, 13%-88% in ACNA, and 30%-85% in AGA), changes that were concurrent with clinical improvements.

CONCLUSION AND CLINICAL IMPORTANCE

An assay based on combined measurements of ACA, ACNA, and AGA is useful as a noninvasive diagnostic test to distinguish dogs with CE/IBD. The test also has the potential to monitor response to treatment.

Evaluation of novel serological markers and autoantibodies in dogs with inflammatory bowel disease

Background

The use of serological markers to diagnose inflammatory bowel disease (IBD) in humans is well‐established. Because of the frequency of IBD in dogs and resources required for its diagnosis with current methods, new approaches are desired.

Objective

The goal is to evaluate novel serologic markers to differentiate clinical cohorts in dogs with gastrointestinal (GI) disease and assess their potential to develop a serum‐based IBD diagnostic test.

Animals

Seventy dogs diagnosed with biopsy‐confirmed IBD, 23 dogs with non‐IBD predominantly acute GI diseases, and 58 normal dogs.

Methods

Prospective control study. ELISA methods were developed to detect autoantibodies to polymorphonuclear leukocytes (APMNA) and calprotectin (ACNA), antibodies against gliadins (AGA), microbial outer membrane porin C (ACA), and flagellins (AFA) isolated from diseased dogs based on clinical and histopathological scoring.

Results

IBD dogs displayed a 39%‐76% prevalence of seropositivity against selected serologic markers that markedly decreased to 0%‐13% in non‐IBD and normal dogs. ROC analysis showed statistical significance in differentiating the cohorts, with seropositivity against OmpC being the highest single performance marker. The combination of markers such as OmpC and APMNA reached specificities of 93%‐99% and 79%‐98% and sensitivities of 76%‐97% and 66%‐86% when comparing IBD versus normal cohorts and non‐IBD cohorts, respectively.

Conclusion and Clinical Importance

Seropositivity of canine immunoglobulins A against selected serologic markers in dogs appears promising in the detection and differentiation of IBD versus other acute GI conditions. Among them, antibody reactivity to Escherichia coli OmpC and canine autoantibodies against polymorphonuclear leukocytes displayed the highest single marker discriminating performance.

Immunohistochemical Profiling of Canine Intestinal T-Cell Lymphomas

Human enteropathy-associated T-cell lymphoma (EATL) is classified into 2 distinct subgroups based on their phenotypes (type I and type II). Canine intestinal T-cell lymphoma can be morphologically classified into large and small cell lymphomas (LCL and SCL, respectively). Their association with human EATL or immunohistochemical and biological features has not been well characterized. In this study, the immunohistochemical profiles of 17 cases of LCL and 33 cases of SCL were evaluated with markers used for human EATL classification. Morphologically, LCL was characterized by sheet-like proliferation of large to moderately sized neoplastic lymphocytes, with scant clear cytoplasm and pleomorphic, irregularly shaped nuclei containing distinctive nucleoli and scattered chromatin. In contrast, SCL was characterized by the proliferation of monomorphic small neoplastic lymphocytes, accompanied by infiltration of nonneoplastic plasma cells. Interestingly, 8 cases demonstrated mixed LCL and SCL morphologies. Granular cytoplasmic expression of granzyme B was observed in most LCL and SCL cases. Membranous expression of CD56 was demonstrated in only 2 of 17 LCL and 0 of 33 SCL cases. Coexpression of CD20 by neoplastic T cells was observed in more SCL cases (16/33; 48%) than LCL cases (1/17; 6%). The CD56-positive cells in 2 cases were negative for CD20. Although canine LCL shares common features with human EATL type I, canine SCL cells and human EATL type II differ in their immunophenotype. Canine intestinal T-cell lymphoma had a homogeneous immunophenotype regardless of cell morphology. The findings of this study may indicate large cell transformation of SCL rather than 2 distinct entities.