Bacterial Infections and the Pathogenesis of Autoimmune Conditions

Bacterial infections are associated with many autoimmune diseases involving chronic inflammation and demyelination. The possible mechanisms of bacterial involvement as aetiological agents or in the exacerbation of these diseases have been investigated intensively. This review focuses the role of bacterial infections in the pathogenesis of autoimmune, inflammatory and demyelinating diseases. Possible modes of pathogenic action of bacteria are discussed, viz. the role of cytokines, Toll-like receptor signalling, the interaction of heat shock proteins with the immune system, and the role of nitric oxide. An auto-regulatory loop might exist in the interaction of bacteria with the host and in pathogenic signal processing. These studies reveal potential therapeutic targets. Abbreviations: AQP4 Aquaporin-4; AS ankylosing spondylitis; CSF cerebrospinal fluid; EAE autoimmune encephalomyelitis; GB Guillain-Barre syndrome; HLA human leukocyte antigens; HSP heat shock protein; IL interleukin; LPS lipopolysaccharides; MAM Mycoplasma arthritidis antigen; MHC [proteins encoded by] major histocompatibility gene complex; MS multiple sclerosis; NK natural killer cells; NMO neuromyelitis optica; NO nitric oxide; NOS nitirc oxide synthase; PCR polymerase chain reaction; RA rheumatoid arthritis; SLE systemic lupus erythematosus; TLR Toll-like receptors; TNF tumour necrosis factor