The gut and RA

Clinically silent inflammatory gut lesions in undifferentiated spondyloarthropathies

Gastrointestinal inflammation or infection can be associated with various forms of arthritis, such as, acute reactive arthritis triggered by enteritis due to gram-negative bacteria or ankylosing spondylitis and peripheral arthritis in relation to Crohn's disease and ulcerative colitis. Using colonoscopy, we have found a high prevalence of clinically silent inflammatory lesions in 38 patients (24 males and 14 females) affected by undifferentiated spondyloarthropathies (SpA). Microscopic inflammatory lesions were present in all the patients. Three patterns of nonspecific chronic inflammatory alterations were observed. No difference was noted between patients taking or not taking nonsteroidal anti-inflammatory drugs. Direct immunofluorescence demonstrated the presence of IgG, IgA, IgM, C3, C4 and fibrinogen in 75% of the specimens examined. The finding of chronic inflammatory gut lesions hypothesizes that a local activation of the immune system depending on the persistence of intestinal microbial antigens or toxins, due to impaired elimination or increased exposition, may have a part in the pathogenesis of SpA.

Intestinal mucosal permeability and rheumatological diseases

Rheumatological disorders frequently have gastrointestinal manifestations and, conversely, intestinal disorders frequently have rheumatological manifestations. The possibility of altered intestinal permeability in arthritic patients may provide the bridge needed to link the two organ systems. The normal intestine absorbs nutrients and excludes the remaining material. If the intestine were less discriminating or 'leaky' then material normally excluded would be able to cross the intestinal mucosa into the lamina propria. An inflammatory response to these antigens, be they dietary, bacterial, or viral in origin, could produce either local or systemic disease. This would depend upon the type of immunological response and the cross-reactivity between the host's antigens and the absorbed antigens. This theory could account for the postulated relationship between intestinal abnormalities and the pathogenesis of some forms of arthritis.

Development of a new radiographic scoring system using digital image analysis

A scoring system using computerised analysis of digital stored images of knee radiographs has been developed. Measurement is based on the assessment of joint space size. It is sensitive, rapid, and reproducible. Plain radiographs are positioned on an acetate grid; a computer generated grid is superimposed on a digital image of the radiograph viewed on a closed circuit television monitor and the joint space measured automatically. Area and distance have been assessed; area measurements are more reproducible. Application of microcomputer based digital image analysis to radiological scoring systems is an important step in understanding the nature and progression of arthritis.