Final answer:
Autoimmunity is a condition that arises when the body's immune system mistakenly forms antibodies against its own red blood cells, leading to a type II hypersensitivity reaction.
Step-by-step explanation:
A condition where the body forms antibodies against its own red blood cells is known as autoimmunity. This occurs in various autoimmune diseases where autoantibodies target self-components by mistaking them as foreign. For example, in autoimmune hemolytic anemia, antibodies directed against self-red blood cells could lead to their destruction. This process is a type of type II hypersensitivity reaction where antibody binding and activation of complement result in cell damage, typically against red blood cells.
Examples include hemolytic transfusion reaction (HTR) and hemolytic disease of the newborn (HDN), which involve the coating of RBCs by antibodies, leading to lysis and phagocytosis.