Role of Gut Microbiota and Infectious Burden in the Development of Autoimmune and Allergic Diseases

The human gut is the natural niche to an enormous and complex community of commensal bacteria of more than 1000 different species. Because of intimate relation between gut microbiota and host immune system¡ gut microbiota effectively modulate the development of both the innate and adaptive immune system. Several scientists have worked in this field and linked some members of the gut microbiota to autoimmune diseases. So far¡ significant attention has been given on the role of gut microbiota in gastrointestinal tract related autoimmune diseases such as inflammatory bowel disease (IBD). Several studies have identified the dysbiosis of specific microbiota in IBD patients. A reduction in Firmicutes and Bacteroides species and an overgrowth of proteobacteria have been observed in IBD patients.1¡2 Many studies have demonstrated the role of gut microbiota in modulating the systemic immune components besides the local gut immune system. Hence¡ gut microbiota have been linked to the development of extra-intestinal autoimmune disorders such as rheumatoid arthritis and Type 1 diabetes. 3¡4 Multiple factors such as genetics¡ age¡ and environment might contribute to the development of autoimmune diseases. Microorganisms such as viruses and bacteria are the major environmental factors .