Inflammatory bowel disease. The case for an infectious etiology

Clinical aspects and pathophysiology of inflammatory bowel disease

The chronic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are recognized as important causes of gastrointestinal disease in children and adults. In this review we delineate the clinical manifestations and diagnostic features of IBD. In addition, we summarize important recent advances in our understanding of the immune mediators of intestinal inflammation. This information has led to new therapeutic approaches in IBD. Further, we discuss the considerable data that point to the significance of genetic factors in the development of IBD and the genetic loci which have been implicated through genome-wide searches. The commensal bacterial flora also appears to be a critical element, particularly in regards to Crohn's disease, although the precise role of the bacteria in the disease manifestations remains unclear. Current investigations promise to yield fresh insights in these areas.

Adaptation of bacteria to the intestinal niche: probiotics and gut disorder

The gastrointestinal tract is a complex ecosystem host to a diverse and highly evolved microbial community composed of hundreds of different microbial species. The interactions that occur between this complex microbial community and the human host have become the focus of scientific research due to increases in the incidence of illnesses associated with deficient or compromised microflora (e.g., gastrointestinal tract infections, inflammatory bowel disease (Crohn's disease and ulcerative colitis), irritable bowel syndrome, antibiotic-induced diarrhea, constipation, food allergies, cardiovascular disease, and certain cancers). Effective multidisciplinary research programs now complement conventional microbiology with molecular ecology techniques to provide culture-independent analysis of the gastrointestinal ecosystem. Furthermore, as we acquire an understanding of gut microflora composition and processes such as intestinal adherence, colonization, translocation, and immunomodulation, we are also elucidating mechanisms by which these can be influenced. This knowledge not only allows scientists to define the activities and interactions of "functional food"-borne beneficial bacteria in the gut, but will also provide the scientific basis for the development of innovative biotechnology-based products tailored to prevent specific diseases and promote overall human gastrointestinal health.

Analysis of culture filtrate and cell wall-associated antigens of Mycobacterium paratuberculosis with monoclonal antibodies

Proteins secreted by Mycobacterium species have been suggested as major immune targets in the early phase of infection. In this study, we sought to identify specific antigens in culture filtrates and in soluble cell extracts of Mycobacterium paratuberculosis. The release of antigens into the culture medium during growth of the bacilli and the distribution of specific epitopes within the Mycobacterium species were investigated by immunoblot analysis with monoclonal antibodies (MAbs) raised against M. paratuberculosis antigens. MAb B6A interacted with a cellular antigen with an apparent molecular mass of 34.5 kDa in lysates of M. paratuberculosis. MAb B6A did not interact with lysates from any other mycobacterial species, suggesting recognition of an M. paratuberculosis species-specific epitope. MAb FL1-A1 reacted with an antigen of 44.3 kDa in M. paratuberculosis and a 9-kDa antigen in Mycobacterium kansasii. MAb PII-B1 reacted with concanavalin A (ConA)-binding cellular and filtrate molecules of M. paratuberculosis and with lysates of Mycobacterium kansasii and Mycobacterium avium 18. The affinity-purified glycosylated antigens migrated as a diffuse band of between 35 and 45.6 kDa and reacted strongly with ovine and bovine paratuberculosis serum and polyclonal serum against M. tuberculosis lipoarabinomannan antigens. These glycoconjugates were the earliest antigens detected in culture filtrates of M. paratuberculosis. Deglycosylation of the ConA-binding molecules with alpha-mannosidase enzyme abolished the reaction with MAb PII-B1 and with bovine but not ovine paratuberculosis serum, suggesting selective immunogenicity in the different animal species.

Fulminant herpes colitis in a patient with Crohn's disease

Herpes simplex virus (HSV) is a well-recognized cause of gastrointestinal infection, most commonly in patients with underlying immunodeficiency. The esophagus, perianum, and rectum are the most common sites of involvement; however, extensive colitis is rare. We describe a woman with Crohn's disease who developed pathologically proven HSV colitis. We review the literature and present the possible implications of the diagnosis.