Rotavirus antibodies in Crohn's disease and ulcerative colitis

The role of prolonged viral gastrointestinal infections in the development of immunodeficiency-related enteropathy

Patients with primary immunodeficiencies are prone to develop enteropathy of unknown pathogenesis. We hypothesize that ineffective clearance of gastrointestinal pathogens, particularly viruses, in combination with defective immune regulation may cause inflammatory enteropathy in certain immunodeficient hosts. We reviewed publications related to prolonged enteric viral infection, immunodeficiency, and the subsequent development of inflammatory enteropathy. Prolonged infection with especially enteroviral infections was reported more often in immunocompromised hosts than in healthy individuals. Protracted enteric viral shedding was not always associated with the presence or duration of gastrointestinal symptoms. The development of immunodeficiency-associated enteropathy after prolonged viral infections was described in sporadic cases. Clinical consequences of viral gut infections in immunocompromised hosts comprise isolation issues and supportive care. Prospective studies in cohorts of immunodeficient patients are required to study the impact of prolonged enteric viral replication with respect to the pathogenesis of non-infectious enteropathy.

Current knowledge and systematic review of viruses associated with Crohn's disease

The aetiology of Crohn's disease (CD) is currently unknown. A viral trigger was proposed more than 40 years ago and has been the focus of many investigations. We summarised the current literature surrounding the association between viruses and CD and conducted a systematic review of all studies investigating this association quantitatively. Studies were identified by searching for 13 specific virus names or the general term 'virus' and 'Crohn's disease' in search engines PubMed and OVID. A total of 1315 studies were identified, of which 78 studies had a laboratory result. Of the 78, 46 case-control studies met all the inclusion criteria for forest plot analysis. The most common viruses studied were EBV, CMV and measles virus (MV). Forest plot analysis for each virus was carried out (fitted using random effects) and identified evidence of an association between CD and CMV (risk ratio [RR] 1.602, 95% confidence interval [CI] 1.069 to 2.400) with some suggestion that EBV may also be associated with CD (RR 1.366, 95% CI 0.996 to 1.873). However, there was evidence of large heterogeneity in the results from the identified studies for EBV. There was little evidence of an association with CD for MV, human herpes virus 6, human herpes virus 8, human simplex virus, varicella-zoster virus, mumps virus, Rubella virus, rotavirus, norovirus and adenovirus. There is still some question around whether CD is associated with the presence of a currently known virus.

Detection of immunoreactive antigen, with a monoclonal antibody to measles virus, in tissue from a patient with Crohn's disease

Using immunofluorescence (IF), we investigated reactive antigens present in Crohn's disease patients with monoclonal antibodies derived from cells infected with measles virus, but not with the subacute sclerosing panencephalitis virus. During immunoblotting, one monoclonal antibody (mAb 86) reacted with a polypeptide with a molecular weight of 36,000 dalton (M; matrix protein) in measles virus-infected cells. This monoclonal antibody displayed a positive reaction only with tissues from patients with Crohn's disease by the IF test. It did not react with samples from patients with other chronic inflammatory bowel diseases, such as ulcerative colitis. Other monoclonal antibodies to the measles virus protein, and monoclonal antibodies to Herpes simplex virus type 1 did not react with the same tissue samples. The role of measles virus infection and/or a viral antigen (possibly the M protein) as a causative agent in Crohn's disease poses a challenging avenue for further research.

Inflammatory bowel disease. The case for an infectious etiology

The infectious hypothesis for IBD is certainly not new. The evidence for an infectious agent is tantalizing but not yet convincing. A failure to demonstrate a specific agent in the inflammatory process could mean that many different organisms are involved, or several organisms that, by themselves, do not cause disease interact. All candidate organisms proposed thus far are compatible with either hypothesis. Nevertheless, interaction between an agent(s) in a host modified by immunologic and genetic factors is still an attractive hypothesis for the cause of these illnesses.

Etiology of inflammatory bowel diseases: where have we been? Where are we going?

The cause or causes of Crohn's disease and of ulcerative colitis remain uncertain. In spite of extensive investigations, searching for immunologic or infectious causes, clear evidence suggesting an underlying etiology is lacking. Recent studies involving mycobacteria suggest that occasional patients thought to have Crohn's disease may indeed be infected with a mycobacterium. However, clear cause-and-effect relationships have not been established. Future efforts at trying to establish the relationship between environmental factors, including infectious agents, and immunologic mediators seem appropriate on the basis of available data. For the present, the causes or cause of these diseases remains obscure.

Lymphocytotoxic and microbial antibodies in Crohn's disease and matched controls

Patients with Crohn's disease and age, sex and seasonally matched healthy controls were studied for cold lymphocytotoxic and a variety of microbial antibodies. Lymphocytotoxic antibody titers were increased significantly in the Crohn's patients compared to controls, but did not correlate with any of the microbial titers. Antibodies to a Pseudomonas-like bacterium and Bacteroides vulgatus were also increased in the patients, but titers to Chlamydia trachomatis, rotavirus and Norwalk virus were not elevated above control values. Analysis of microbial antibody within the patient and control groups revealed a significant (P = .001) correlation between antibodies to the Pseudomonas-like bacterium and Bacteroides vulgatus. The elevated titers to the Pseudomonas-like organisms and B. vulgatus are of potential importance, but their significance is not known at this time. There is no evidence of an increased incidence of infection with C. trachomatis, rotavirus or Norwalk virus in Crohn's disease.

Serum agglutinins to Eubacterium and Peptostreptococcus species in Crohn's and other diseases

Sera from patients suffering from Crohn's and other diseases and from healthy subjects were tested for agglutinins to anaerobic, gram-positive coccoid rods belonging to species of Eubacterium and Peptostreptococcus. Four strains labelled Eubacterium contortum (two strains), Eubacterium rectale and Peptostreptococcus productus were agglutinated by a higher percentage of sera from patients with Crohn's disease than from healthy subjects and from patients with liver and intestinal diseases (including ulcerative colitis), ankylosing spondylitis, granulomatous diseases, diseases of immunity and malignancies. The agglutinins were of the IgG and IgM classes and strain-specific; the titres were low. The results obtained with sera from patients with Crohn's disease and healthy people were subjected to discriminant analysis to estimate the probability, based on the combined results with the four strains, that a patient suffers from Crohn's disease. When sera giving an a posteriori probability greater than or equal to 0.95 (a priori probability = 0.5) were considered positive, the test with four strains had a sensitivity of 54% and a specificity of nearly 100%. The results with sera submitted for diagnosis showed that positive reactions in patients with a diagnosis apparently incompatible with Crohn's disease were within acceptable limits.