Early environmental exposure and the development of lupus.

Systemic lupus erythematosus (SLE) is a complex trait with evidence of polygenic inheritance influenced by environmental factors. However, the precise underlying causes of SLE remain unclear. A number of environmental exposures have been associated with lupus or related autoimmune phenomena. Evidence suggests that some environmental exposures need to be present many years before the onset of SLE. Both SLE and rheumatoid arthritis (RA) can occur in very young children and this supports the possibility that important environmental factors must be present during or before this time. In addition, the immune pathology, including autoantibody production, in adult lupus may begin years before clinical disease. There is also evidence that the developing immune system demonstrates developmental plasticity and can be permanently altered or 'programmed' by the early environment. We describe how early life environmental influences including infectious exposure may lead to autoantibody production in later life thus beginning the journey that leads to autoimmune diseases such as lupus in susceptible individuals.