They demonstrated that when antigen is abundant and generally available throughout the body, rogue autoantibody-generating B cells are deleted and autoimmunity avoided. Conversely, when target antigen is located only in a tissue or organ remote from the germinal centre, B cells capable of reacting against both antigen and 'self' are able to escape the germinal centre and produce autoantibodies.
"Essentially we've shown there's a big hole in self-tolerance when it comes to cross-reactive autoantibodies that can attack organ-specific targets," said Brink.
"Our finding explains a lot about how autoimmune conditions that target particular organs such as the heart or nervous system could develop
after an infection. It also suggests that if you know enough about the disease and the molecular messaging systems involved, it may be possible in future to modulate the germinal centre response."
https://www.sciencedaily.com/releases/2012/11/121109111511.htm