Slipping through the Cracks: Linking Low Immune Function and Intestinal Bacterial Imbalance to the Etiology of Rheumatoid Arthritis

Figure 5

Possible contribution of pathogenic and nonpathogenic environmental factors to autoimmune diseases: low immune function may lead to intestinal bacterial imbalance by failing to prevent the colony formation of pathogenic bacteria (a). In addition decreases in the mucosal barrier function result in increased intestinal mucosal permeability (b). As a result, excess amounts of bacterial components and their toxins and even large molecular, undigested dietary proteins, which share similar amino acid sequences with autologous components such as collagen, cross the mucosal barrier into circulation (c). Some of these exogenous substances can disturb immune homeostasis and result in the development of chronic diseases.