Hepatitis - Causes
The exact mechanism by which viruses cause hepatitis is not entirely understood. It appears that the disease is not caused by the virus itself, but by the body's immune system. The immune system is a network of organs, tissues, cells, and chemicals designed to protect the body against foreign invaders, such as bacteria and viruses.
When a foreign invader enters the body, the immune system begins to respond. It produces chemicals designed to kill the invader. These chemicals are called antibodies. The presence of antibodies in the bloodstream may have other effects on the body, including inflammation, swelling, and other symptoms. It appears that the liver becomes inflamed because of the antibodies produced by the immune system, not because of the virus itself.