THE EXTENDED ‘SELF’: A Perspective on Ecological Autoimmunity

PABLO IGNACIO MARTÍN; PABLO ALEJANDRO SÁNCHEZ; ENRIQUE REWALD

Ljubljana

Congreso; 7th International Congress on Autoimmunity; 2010

Kenes International

It is generally accepted the fact that autoimmunity arises from a breakdown of self-tolerance that enables an organism to mount an immune response against its own constituents. Such definition presupposes a clear depiction of an organism’s individuality. However, by considering an organism as a complex open system in constant exchange of matter and energy with the environment in which it operates, the dividing line between one and the other becomes blurry at best, casting doubt about the traditional static notion of self. In view of the resources the immune system invests in order to achieve a state of tolerance towards a wide variety of foreign antigens, an hypothesis is here forwarded that the environmental dynamics, comprising inner habitat pollution that may also include host derived elements, may contribute to a dynamic redefinition of the immunological self. We may call this the ‘extended self’, and can be exemplified by means of the astonishingly complex equilibrium taking place in the gut between the commensal microflora and the local immune system. From this point of view, rather than a digital (namely, 0 or 1) mechanism, self/non-self-recognition is to be seen as a dynamic threshold-dependent process. By extending the notion towards a community context, each individual’s repercussion on the environment could contribute to establish global pattern tending to jeopardize self/non-self-recognition. This may be a factor to be accounted for when analyzing the asymmetric incidence of autoimmune diseases in developed and under-developed countries.