Peripheral blood and mesenteric lymph node lymphocytes in Crohn's disease

The Role of the Lymphatic System in the Pathogenesis and Treatment of Inflammatory Bowel Disease

Although the number of therapeutic options for the treatment of inflammatory bowel disease (IBD) has increased in recent years, patients suffer from decreased quality of life due to non-response or loss of response to the currently available treatments. An increased understanding of the disease’s etiology could provide novel insights for treatment strategies in IBD. Lymphatic system components are generally linked to immune responses and presumably related to inflammatory diseases pathophysiology. This review aims to summarize findings on immune-mediated mechanisms in lymphoid tissues linked with IBD pathogenesis and (potential) novel treatments. Enhanced innate and adaptive immune responses were observed in mesenteric lymph nodes (MLNs) and other lymphoid structures, such as Peyer’s patches, in patients with IBD and in animal models. Furthermore, the phenomenon of lymphatic obstruction in the form of granulomas in MLNs and lymphatic vessels correlates with disease activity. There is also evidence that abnormalities in the lymphatic stromal components and lymph node microbiome are common in IBD and could be exploited therapeutically. Finally, novel agents targeting lymphocyte trafficking have been added to the treatment armamentarium in the field of IBD. Overall, gut-associated lymphoid tissue plays a key role in IBD immunopathogenesis, which could offer novel therapeutic targets.

Differences in immunophenotyping of mucosal lymphocytes between ulcerative colitis and Crohn's disease

OBJECTIVES

Immunologic studies have characterized the numbers and types of inflammatory cells in diseased inflammatory bowel disease (IBD) mucosa but have yielded conflicting results regarding intestinal lymphocytes activation in IBD. We investigated the levels of lymphocytes subsets, interleukin-2 receptor, transferrin receptor, and T cell receptors in mainly isolated lamina propria lymphocytes. Including intraepithelial lymphocytes of normal colonic mucosa or IBD (ulcerative colitis and Crohn's disease) mucosa to understand the pathogenesis of IBD. We have results from this study.

RESULTS

1) In comparing ulcerative colitis with control, IL-2R (p < 0.05), TR (p < 0.01), and CD3/HLA-DR (< 0.05) showed a significant increase. 2) In comparing Crohn's disease with control, CD3 (P < 0.05), TCR alpha/beta (p < 0.01) and TCR gamma/delta (p < 0.05) showed a significant decrease. 3) In comparing Crohn's disease with ulcerative colitis, CD19 (p < 0.01), TR (p < 0.01), TCR alpha/beta (p < 0.01) and TCR gamma/delta (p < 0.05) showed a significant decrease.

CONCLUSION

From these results, there are increased T cell markers, IL-2R, TR, and CD3/HLA-DR in UC, but differently, decreased CD3, TCR alpha/beta and TCR gamma/delta in CD compared with control. In addition, definitive differences in lymphocytes markers, CD19, TR, TCR alpha/beta and TCR gamma/delta, which are higher in UC than in CD, may elucidate the different immunopathogenesis between UC and CD.

Analysis of T-lymphocyte subpopulations in inflammatory bowel diseases by three-color flow cytometry

In order to better define changes in the relative proportion of peripheral blood T-lymphocyte subpopulations in patients with inflammatory diseases of the bowel, we performed simultaneous three-color fluorescence-activated cytometric (FACS) analysis using fluorophore-conjugated monoclonal antibodies with specificity for CD4, CD8, Leu 8, and CD45RA on 22 normal control subjects, 28 patients with Crohn's disease (CD), 15 patients with ulcerative colitis (UC), and 11 patients with intestinal inflammation secondary to etiologies other than inflammatory bowel disease (NIBD). This staining combination allowed enumeration of distinct T-cell subpopulations as follows: virgin CD4+, recall antigen helper T cells, nonspecific B-cell helper T cell, virgin CD8+, cytotoxic effector and suppressor effector and recall antigen cytotoxic T cells based on a synthesis of published functional analyses. No differences in the proportion of CD4+ or CD8+ cells or in the CD4+/CD8+ ratios were evident when UC and NIBD patients were compared to normal subjects. A significant reduction in the proportion of CD4+ cells and an increase in CD8+ cells was observed, however, in the CD group. When two-color analysis was performed, several significant differences in the proportions of circulating lymphocytes were seen. Specifically, these included significant increases in the number of CD4+, Leu 8- (P < 0.01) cells in all disease groups and an increase in CD4+, CD45RA+ cells in the NIBD group. Conversely, significant decreases in the proportions of CD8+, Leu 8+ (P < 0.01) cells were evident in the Crohn's disease group.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated numbers of peripheral T cells in inflammatory bowel diseases displaying T9 antigen and Fc alpha receptors

Elevated numbers of peripheral T cells expressing the activation associated antigen T9 are found in patients with active Crohn's disease. Expression of T9 is found to be correlated to the activity of the disease. However the presence of activated peripheral T cells is not restricted to Crohn's disease, but could also be found in other maladies with a supposed involvement of the immune system, e.g. ulcerative colitis, sarcoidosis, connective tissue disease and after organ transplantation. Significant elevation of the number of activated T cells could not be detected in cases of viral or bacterial enteritis and coeliac disease. Analysing the subset of T9 positive T cells with regard to the expression of Fc alpha receptors, a significantly increased number of Fc alpha receptor positive cells, within the subset of T9 positive cells in the peripheral blood of patients with Crohn's disease and ulcerative colitis was found, which could not be demonstrated in the case of other diseases analysed in this study. Thus the T9+ Fc alpha receptor +T cell subset may be considered to be pathognomonic for inflammatory bowel diseases. Analysis of the regulatory properties of T9 positive cells, with regard to the immunoglobulin isotype secretion in a pokeweed mitogen stimulated autologeous B cell assay, suggests that peripheral T9 positive T cells are involved in the suppression of IgA synthesis or secretion.

Involvement of the immune system in the pathogenesis of Crohn's disease. Expression of the T9 antigen on peripheral immunocytes correlates with the severity of the disease

Peripheral lymphocyte cells from patients suffering from Crohn's disease were analyzed for the expression of the "activation" antigens T9 and HLA-DR on their cell surface. It was found that high numbers of "activated" lymphocytes, the majority of which have proven to be T cells, could be detected in patients with active Crohn's disease, whereas in healthy controls and inactive disease only a small subfraction of lymphocytes was positive for these antigens. This difference was highly significant (p = 0.0001). Within the subpopulation of T9-positive cells the ratio between T4- and T8-positive cells is about 1.8 (compared with 2.0 in the total T-cell subset). All HLA-DR-positive, non-B and non-glass-adherent cells could be detected in the T9-positive cell fraction. The presence of T9 antigens was found to correlate with the grade of severity of the disease as assessed by a Crohn's disease activity index. The presence of high amounts of T cells exhibiting this antigen is not restricted to Crohn's disease but is thought to be of importance as a marker for the involvement of the immune system in other maladies as well. Nevertheless, the determination of T9 antigen is expected to provide objective data reflecting the severity of Crohn's disease.

Influence of nutritional status on immune functions in patients with Crohn's disease

Nutritional status and immune function were correlated with clinical features in 56 patients with Crohn's disease. These were divided arbitrarily into either undernourished or well nourished groups according to whether their midarm circumference was below or above 90% of ideal standard. Results were also compared with 33 patients with ulcerative colitis and 28 normal subjects. Undernourished patients with Crohn's disease had significantly reduced total lymphocyte and T lymphocyte counts and a reduced proportion of monocytes that ingested latex particles. Well nourished patients with Crohn's disease were similar to the two control groups. Twenty one undernourished patients with Crohn's disease were also followed during the course of two to four months' nutritional treatment with an enteral supplement. Nutritional therapy was associated with significant anthropometric gains as well as significant rises in total lymphocyte and T lymphocyte counts. Serum orosomucoids were significantly higher in undernourished patients and decreased significantly during nutritional therapy. The results show that undernutrition and disease acuity may be associated with reduced immunological competence in patients with Crohn's disease, but all these measurements can be improved by short term nutritional treatment.