Alloimmunity is an immune response to foreign
antigens (alloantigens) from members of the same species. The body attacks mainly transplanted tissue and even the
fetus in some cases. Alloimmune response results in
graft rejection, which is manifested as deterioration or complete loss of graft function. In contrast,
autoimmunity is an immune response to the self's own proteins. (The
allo- prefix means "other", whereas the
auto- prefix means "self".)