The autoimmune system is like an army with all kinds of soldiers from the air force, navy and army, which will destroy any enemy once it invades the body. Several of the most important organs in the immune system are the bone marrow, which produces all types of blood cells. The cells that are produced from the bone marrow are sent to the thymus gland. The thymus gland is like a training camp. As a child, it is easy to have an enlarged thymus gland because you have not trained enough troops. As a person grows up, the thymus gland slowly shrinks, but that doesn’t mean that it is no longer functional. The tonsils are also part of the immune system and should not be cut off lightly. The spleen contains many V cells, which produce various types of antibodies. When a person gets a cold or a child gets a vaccination, the spleen swells slightly. This is a natural phenomenon, as it is desperately trying to generate weapons to defend itself against foreign enemies. The lymph acts as a filter to concentrate all the enemies and then the immune cells will destroy them. Therefore, the lymph will be hard to touch when you have a cold, which means that the immune system in the body is fighting a war, and after the cold is over, it will naturally soften down. The appendix is a very important part of the immune system, fighting off all kinds of infections in the lower abdomen. The white blood cells in the blood are all immune cells. White blood cells are divided into two categories, the first is called T-cells and the other is called V-cells. v-cells function in producing various antibodies, and this is equivalent to weapons, bullets in the army. When there is a war, there are dead soldiers, and it is necessary to remove the dead cells. This relies on a group of cells trained by our thymus.