SUMMARY Crohn's disease is a chronic inflammatory bowel disease of unknown cause, affecting approximately 1.4 million North American people. Due to the similarities between Crohn's disease and Johne’s disease, a chronic enteritis in ruminant animals caused by Mycobacterium avium paratuberculosis (MAP) infection, MAP has long been considered to be a potential cause of Crohn's disease. MAP is an obligate intracellular pathogen that cannot replicate outside of animal hosts. MAP is widespread in dairy cattle and because of environmental contamination and resistance to pasteurization and chlorination, humans are frequently exposed through contamination of food and water. MAP can be cultured from the peripheral mononuclear cells from 50 to 100% of patients with Crohn's disease, and less frequently from healthy individuals. Association does not prove causation. We discuss the current data regarding MAP as a potential cause of Crohn's disease and outline what data will be required to firmly prove or disprove the hypothesis.
Background:RANTES (regulated on activation, normal T cell expressed and secreted) expression is increased in inflammatory bowel disease (IBD). RANTES is produced at higher levels in granulomatous conditions, so increased RANTES expression can be expected in Crohn’s disease compared with ulcerative colitis.Aim:To compare RANTES expression between intestinal biopsy specimens of patients with Crohn’s disease and those with ulcerative colitis.Materials and methods:A prospective study of patients presenting with lower gastrointestinal symptoms at the Bahrain Specialist Hospital from July 2004 to April 2005 was carried out. Endoscopic colonic biopsy specimens were taken from every patient and subjected to (a) routine haematoxylin and eosin staining examination by light microscopy, (b) immunohistochemistry for examination of RANTES protein expression by light microscopy and (c) in situ hybridisation for examination of RANTES mRNA expression by light microscopy. RANTES expression was assessed and quantified.Results:58 patients were enrolled to the study. Of them, 40 had IBD (21 had Crohn’s disease and 19 had ulcerative colitis), 15 were controls with normal colonic biopsy results or non-inflammatory lesions and 3 had colonic inflammatory lesions other than IBD. RANTES expression in lymphocytes or histiocytes was significantly higher (p = 0.04) in new patients with ulcerative colitis than in those with Crohn’s disease analysed by immunohistochemistry (IHC).Conclusion:RANTES expression in lymphocytes or histiocytes is significantly higher in patients with ulcerative colitis than in those with Crohn’s disease. Hence, RANTES IHC can be an effective method for distinguishing between biopsy specimens of patients with ulcerative colitis from those of patients with Crohn’s disease, where routine histological features are indeterminate. RANTES IHC may prove to be a useful technique for identifying early or equivocal granulomas.
Gastrointestinal tract (GIT) involvement by cytomegalovirus (CMV) infection is well-recognized in immunosuppressed patients but is uncommon in immunocompetent hosts. The colon and esophagus are the most frequently affected sites with punched out ulcers being the characteristic mucosal lesion. CMV-induced pseudotumor is an exceptionally rare presentation, especially in immunocompetent hosts. A 76-year-old immunocompetent female presented with abdominal pain and constipation. Colonoscopy revealed an ulcerated polypoidal tumor-like mass in the anorectal region. Biopsy of the lesion showed large basophilic intranuclear inclusions which were positive for CMV on immunohistochemical staining. The patient responded to 2 weeks of antiviral therapy with complete resolution of the mass. Although rare, pseudotumors associated with CMV infection should be considered in the differential diagnosis of tumorous lesions of the GIT.
The incidence rate of Crohn's disease in Bahrain is comparable to the U.S.A and has increased for men and women in all age groups. Crohn's disease clusters were common among families and included up to 3 generations consistent with presence of a common source or common genetic factors.
A 71-year-old female patient was admitted with intractable diarrhea and abdominal distention following several courses of broad spectrum antibiotic therapy. Colonic biopsy revealed pseudomembranous colitis with foci of signet ring cell (SRC) change. The SRCs possessed bland nuclei and were confined to the basement membranes of the crypts with no infiltration into the lamina propria. Benign SRCs in pseudomembranous colitis is an uncommon phenomenon. Awareness of this rare, but potential pitfall is of utmost importance to avoid a misdiagnosis of SRC carcinoma.
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