Final answer:
Autoimmunity is a type of hypersensitivity to self antigens that affects approximately five percent of the population. In myasthenia gravis, antibodies target muscle cell receptors, causing muscle weakness. In systemic lupus erythematosus, autoantibodies response to DNA and proteins cause systemic diseases.
Step-by-step explanation:
Autoimmunity is a type of hypersensitivity to self antigens that affects approximately five percent of the population. Most types of autoimmunity involve the humoral immune response. Antibodies that inappropriately mark self components as foreign are termed autoantibodies.
In patients with the autoimmune disease myasthenia gravis, muscle cell receptors that induce contraction in response to acetylcholine are targeted by antibodies. The result is muscle weakness that may include marked difficultly with fine and/or gross motor functions. In systemic lupus erythematosus, a diffuse autoantibody response to the individual's own DNA and proteins results in various systemic diseases.