Martin Zeitz

Intestinal T-cell lymphoma: a reassessment of cytomorphological and phenotypic features in relation to patterns of small bowel remodelling

Intestinal T-cell lymphoma (ITCL) is an uncommon entity among primary gastrointestinal lymphomas. In this study we evaluated tumours from 20 patients presenting with (n=8) or without (n=12) a history of coeliac disease (CD). Neoplastic lesions were composed of predominantly small (n=4), small-to-medium (n=2), medium/mixed-to-large (n=7) or large and anaplastic (n=7) cells. Different patterns of tumour growth and remodelling of the small bowel wall were observed. Pattern a (n=4) was characterized by an intramucosal spread of small tumour cells with a small growth fraction. This pattern resembles mucosal inflammation in CD. In pattern b (n=2), ulcerated solitary or multiple tumours composed of small to medium-sized cells were observed. The adjacent or distant mucosa showed a nearly normal architecture. In pattern c (n=7), ulcerated lesions were composed of medium-sized to large cells. Mucosal flattening occurred in all segments infiltrated by lymphoma. In pattern d (n=7), bowel remodelling was observed along the small intestine even at sites not affected by lymphoma. The main neoplastic lesions were composed of pleomorphic large or anaplastic cells frequently expressing the CD30 molecule. Intramucosal spread of a small epitheliotropic T-cell population was observed in the vicinity or even at distant segments of the small bowel. The demonstration of clonal rearrangements of T-cell receptor genes helped to trace widespread occurrence of this small intraepithelial neoplastic component. We suggest that different features of tumour cells such as the expression of activation antigens may contribute to the remodelling of small bowel mucosa. The addition of immunophenotyping data to macroscopic and microscopic features of specimens provided evidence that this uncommon lymphoma exhibits a spectrum in cytological composition and growth patterns. However, despite the considerable heterogeneity of the cases analysed, most of them shared a characteristic immunohistochemical profile (CD3+, CD8+/−, CD103+), further substantiating the view that ITCL is the neoplastic equivalent of an intraepithelial T-cell subset of the small intestine. This phenotype and the intraepithelial accumulation of lymphoma cells observed in the surviving mucosa are clues to the diagnosis of this clinicopathological lymphoma entity characterized by a broad range of morphological expressions.

Increased matrix metalloproteinase 2 concentration and transcript expression in advanced colorectal carcinomas

Abstract. Colorectal cancer is one of the most common malignant tumors and entails a relatively poor prognosis. Clinical outcome depends on the extent of local and metastatic tumor spread. Results of in vivo and in vitro studies suggest that the balance between matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases TIMPs) is altered in neoplasia, contributing to the invasive and metastatic properties of malignant tumors. We quantified tissue concentrations of MMP-2 and TIMP-2 in 65 malignant colorectal lesions and corresponding normal mucosa by enzyme-linked immunosorbent assay, western blotting, and in situ hybridization. In situ hybridization and western blot analyses demonstrated a clear increase in both stromal expression of MMP-2 transcripts and protein in primary carcinomas. The protein concentration of MMP-2 was higher in all tumor stages, except stage I tumors, than in normal mucosa and adenomas. MMP-2 concentrations were not related to tumor differentiation or to colonic versus rectal location. Surprisingly, the MMP-2 concentration was not increased in metastases. Interestingly, tissue concentrations and epithelial mRNA expression of TIMP-2 decreased significantly in primary colorectal cancer (UICC stages III and IV) but increased in metastases. Therefore an increased ratio of MMP-2 to TIMP-2 is strongly associated with advanced tumor stages, but a decreased ratio was observed in metastases. These findings suggest that the MMP-2:TIMP-2 ratio may prove useful as a marker of local invasion but not of metastasis in colorectal cancer.

Pattern of mucosal adaptation in acute and chronic pouchitis

PURPOSE: Variant pathological changes have been observed in ileoanal pouches, including inflammation, villous atrophy, and crypt hyperplasia. Therefore, we investigated the type and degree of mucosal adaptation in patients with ulcerative colitis and familial adenomatous polyposis. METHODS: Forty-two patients with ulcerative colitis and 14 patients with familial adenomatous polyposis with ileoanal pouches were assessed. Samples were taken from three months to eight years after creation of an ileoanal pouch. Mucosal architecture was examined by morphometry after microdissection. RESULTS: Structural changes of the mucosa can be categorized into three groups. Compared with preoperative values, patients without pouchitis (73 percent) has only minor decrease of villous length (402µmvs. 540µm) and increase in crypt depth (274.5µmvs. 177µm). In patients with acute pouchitis (20 percent), a slight increase in villous length (477µmvs. 402µm) and pronounced crypt hyperplasia (376µmvs. 274.5µm) was observed compared with noninflamed ileoanal pouches. In contrast, in patients with chronic pouchitis (7 percent), severe villous atrophy (62.5µm) and crypt hyperplasia (543µm) was found. CONCLUSIONS: Minor structural changes of ileoanal pouch mucosa develop early as an adaptive response to a new environment. Only in a small group of patients with chronic pouchitis does severe villous atrophy and crypt hyperplasia of the ileoanal pouch mucosa develop, most likely as a consequence of mucosal inflammation.

Activation of β1 integrins mediates proliferation and inhibits apoptosis of intestinal CD4‐positive lymphocytes

A characteristic of lamina propria lymphocytes (LPL) is their low proliferative response to stimuli of the CD3 pathway. β1 integrins were expressed on LPL; however, their functionis unknown. Therefore, we determined whether β1 integrins contribute to T cell responses by providing costimulatory signals. Integrins on CD4+ LPL of controls and patients with inflammatory bowel disease were characterized by flow cytometry. Cells were stimulated by anti‐CD3 or anti‐CD2 antibodies either alone or in combination with a stimulatory β1 integrinantibody (12G10). Proliferation and apoptosis were measured by [3H]thymidine pulsing or flow cytometry. Cytokine mRNA and apoptosis‐related transcripts were quantified by reverse transcriptase‐PCR. We demonstrated that β1 integrin costimulation restored CD3‐induced proliferation of CD4+ LPL and reduced activation‐induced apoptosis. Activation of β1 integrins by addition of 12G10 antibody to CD3‐stimulated cells restored their capacity to express proinflammatory cytokine transcripts. Further, expression of the activated form of β1 integrins was significantly elevated on LPL from inflamed mucosa. These studies demonstrate that β1 integrin costimulation modulates the response of LPL after TCR stimulation. An increased expression of activated β1 integrins on LPL in intestinal inflammation may abolish their unresponsiveness to antigens and perpetuate the inflammatory process.

CASE REPORT: Groove Pancreatitis

The German term Rinnenpankreatitis, later literally translated to “groove pancreatitis,” was first used in 1973 by Becker to describe a segmental type of chronic pancreatitis, which involves the anatomic space (“groove”) between pancreatic head, common bile duct, and duodenum (1). In 1982, members of Becker’s group reported 30 cases of groove pancreatitis among 123 resectates after duodenopancreatectomy for chronic pancreatitis (2). They distinguished between a genuine and a segmental form, using the term “pure groove pancreatitis” in cases where scarring was only found in the groove, “segmental groove pancreatitis” if dorsocranial parts of the pancreatic head were also involved. The main morphologic features included replacement of pancreatic parenchyma by scar tissue in the segmental form and at most minimal dilatation of the biliary duct. Cicatrization and stenosis of the duodenal wall, accompanied by hyperplasia of Brunner’s glands has often been identified. Cuffing or encasement of the common bile duct was present in “almost all” specimens, while duct stenosis was seen in 67% and 27% of pure and segmental forms, respectively. The authors concluded that these features might help to distinguish the disease from pancreatic carcinoma, where hyperplasia of Brunner’s glands is usually absent, duodenal stenosis less frequent, and tubular bile duct stenosis rare. Pancreatic carcinoma instead usually shows irregular stenosis of biliar and pancreatic duct. No significant differences in patients’ age, sex, or alcohol consumption have been detected when comparing with patients with segmental or nonsegmental forms of chronic pancreatitis. A history of peptic ulcer disease was markedly more frequent in the segmental form. Cicatrization in this anatomical space following acute pancreatitis in pancreatic heterotopies is discussed as the most probable cause for groove pancreatitis. In a large study with a series of 600 pancreatic resections for chronic pancreatitis, 12 and 39 showed typical features of pure and segmental groove pancreatitis, respectively (3, 4). In an additional 66 patients, a nonsegmental chronic pancreatitis involved the groove. Although already described more than 25 years ago, this condition is virtually unknown to most clinicians, and only a few cases have been reported from authors except those who created the term (5–11). Even some major textbooks on gastroenterology do not mention the existence of a segmental type of chronic pancreatitis. Therefore, it is frequently not included in differential diagnosis of pancreatic head enlargement. We report two cases of groove pancreatitis, initially mistaken as pancreatic or duodenal carcinoma, and describe criteria, that might be helpful identifying this condition.

32/67-kD laminin receptor expression in human colonic neoplasia: elevated transcript levels correlate with the degree of epithelial dysplasia.

Objective:The 32/67-kD laminin receptor is thought to be involved in tumor cell migration and metastasis formation, and enhanced expression was observed in human colorectal carcinoma. Our objective was to investigate further the expression of the 32/67-kD laminin receptor RNA in human colonic carcinogenesis.Methods:We obtained sections of human colonic tissues in various stages of malignant transformation and analyzed them by in situ hybridization.Results:Normal colonic mucosa displayed a gradient between crypt base and surface epithelium with lowest receptor RNA levels in superficial epithelial cells. Increased laminin receptor RNA expression was observed in epithelial cells of adenomas with positive correlation between transcript levels and the degree of epithelial dysplasia. At variance with published results, we did not observe significant differences in 32/67-kD laminin receptor transcripts between adenomas with high-grade dysplasia and invasive adenocarcinoma. However, adenocarcinoma metastases displayed significantly higher laminin receptor RNA levels than high-grade adenomas and primary carcinomas.Conclusions:We propose a two-step mechanism which controls first, upregulation of laminin receptor RNA before the acquisition of an invasive phenotype in dysplastic epithelial cells, and second, a further upregulation in metastatic cells during the adenoma–carcinoma sequence of the colon.

Increased expression of interleukin-12 receptor β2 on lamina propria mononuclear cells of patients with active Crohn's disease

HeadingAbstractn Background and aims. Since interleukin-12 is pathogenetically involved in Crohns disease (CD) but not in ulcerative colitis (UC), expression and mechanisms of induction of interleukin-12 receptor (IL-12R) subunits β1 and β2 were analyzed in lamina propria mononuclear cells (LPMNC) of patients with CD and UC.n Patients and methods. LPMNC from patients with CD (n=17), UC (n=14), and controls (n=19) were isolated by standard techniques. IL-12Rβ1 and IL-12Rβ2 transcripts were semiquantified by RT-PCR, and expression of IL-12Rβ2 chain was characterized by flow cytometry. LPMNC were activated by cross-linking with anti-CD3 antibodies and B7-1 costimulation.n Results. IL-12Rβ1 and IL-12Rβ2 transcript concentrations were higher in inflamed specimens than in noninflamed segments of patients with CD but not in UC. Increased percentage of mucosal CD4+/IL-12Rβ2+ cells was observed in active CD, but not UC. In vitro stimulation of LPMNC with anti-CD3 antibodies resulted in an increase in IL-12Rβ1 transcripts irrespective of B7-1 mediated costimulation (84% and 95%, respectively). However, increased expression of IL-12Rβ2 mRNA (110%) was detected only after B7-1 costimulation.n Conclusion. Our data indicate that increased mucosal expression of IL-12Rβ2 on LPMNC in CD but not in UC may be the result of B7-1 costimulation. Modulation or inhibition of IL-12Rβ2 expression on LPMNC could provide a selective therapeutic approach in CD.

The in vitro anti-inflammatory effects of recombinant anti-CD25 immunotoxin on lamina propria T cells of patients with inflammatory bowel disease are not sufficient to cure experimental colitis in mice

Abstract.Background and aims: In chronic inflammatory bowel disease (IBD) such as Crohns disease and ulcerative colitis an aberrant mucosal immune regulation is observed accompanied by upregulation of proinflammatory cytokines. Lamina propria T cells of inflamed mucosa have an activated phenotype characterized by increased expression of surface markers such as CD25. We therefore determined the anti-inflammatory effect of a recombinant immunotoxin consisting of an anti-CD25 single chain variable fragment (scFv) fused to a deletion mutant of Pseudomonas exotoxin A [RFT5(scFv)ETA′] on isolated lamina propria lymphocytes of patients with IBD and in the murine model of trinitrobenzene sulfonic acid (TNBS) induced colitis. Patients and/methods: Lamina propria lymphocytes of 25 patients with IBD and 19 control patients were stimulated in absence or presence of RFT5(scFv)ETA′. Interferon-γ production was determined in the supernatant by ELISA and the induction of apoptosis by flow cytometry after propidium iodide staining. BALB/c mice received TNBS intrarectally and were treated with RFT5(scFv)ETA′. Results: In vitro the administration of RFT5(scFv)ETA′ significantly reduced interferon-γ production and increased apoptosis in lamina propria lymphocytes isolated of inflamed mucosa. However, this contrainflammatory regulation did not result in gain of weight or increased life span in experimental colitis in vivo. Conclusion: In addition to the downregulation of the proinflammatory cytokine in vitro, RFT5(scFv)ETA′ induced neither a direct nor a bystander effect in an in vivo model of colitis. Therefore our data do not support potential therapeutic implications of targeting CD25 by RFT5(scFv)ETA′ in chronic IBD.

Mucosal HIV Infection: A Paradigm for Dysregulation of the Mucosal Immune System

Publisher Summary The gut-associated lymphoid tissue (GALT) comprises an enormous amount of immune cells and the rectal mucosa is most likely the portal of entry of human immunodeficiency virus (HIV) in the major risk group for HIV infection in industrialized countries, namely, homosexual and bisexual men. HIV may enter the host by direct inoculation in the blood stream or by close contact with mucosal surfaces. In the peripheral blood HIV infects the helper/inducer subset of T lymphocytes by the high-affinity binding of its envelope glycoprotein, gpl20, to the CD4 molecule. The CD4 receptor is present in high density on the helper T lymphocyte subset, in a lower density on many cells of the monocyte-macrophage lineage, and on certain other cell types. This chapter presents data on mucosal HIV load in comparison to the peripheral blood. Then, consequences of HIV infection on the mucosal T-cell response and the humoral immune response are discussed. Finally, data are presented which indicate that intestinal mucosal structure and function are disturbed in HIV-infected patients.

Endomicroscopy in Acute Graft-versus-Host Disease

Infections and acute graft-versus-host disease (GvHD) are severe complications following allogeneic stem cell transplantation. GvHD commonly affects the skin, the gastrointestinal tract and the liver. The consequence of acute GvHD is the life-threatening destruction of vital organ functions.