Immune re-education following autologous hematopoietic stem cell transplantation.

The encounter with different environmental antigens during immune maturation from childhood through early adulthood could play a role in the development of autoimmune disease in individuals with a susceptible genetic background. Autologous haematopoietic stem cell transplantation (HSCT) is an experimental treatment for autoimmunity that could offer a second possibility to correct for an aberrant immune reactivity. The premise is that eradication of the existing and pathogenic immune repertoire, in combination with the reinfusion of precursor cells, could reset the immunological clock to an earlier, latent phase of disease. Re-education of the adaptive immune system would occur during the reconstitution of cells under extreme lymphopenia, in which the antigenic priming takes place with a different sequence and timing than during the previous immunological history of the individual, resulting in a different immune repertoire. In this article, we discuss different mechanisms that could contribute to the development of tolerance during immune re-education and address the role of immune renewal and the qualitative reshaping of immunological memory.