The skin is the largest organ in the body. In addition to providing thermoregulation, sensation, and allowing secretion, the first and most basic thing the skin provides is protection. We are constantly exposed to germs. Our skin provides us with a physical barrier to the outside environment. When our skin is damaged, the greatest worry is infection. For example, burn victims are extremely prone to infection.
In situation where the skin is severely damaged and will not heal properly on its own, Skin grafts are performed. It involves removing the damaged skin and “grafting” healthy skin onto that area. The hope is that the new skin will take and that area of severe damage can begin to heal. Different types of skin grafts can be done.
If the person has healthy skin on their body, their own skin can be removed and grafted onto the area of damage, called an autologous skin graft. If that is not possible, the skin for the graft must be obtained from a donor. If the patient has an identical twin that donates skin to be grafted, that is an Isogeneic (Ice-oh-jenick) skin graft. The chances of rejection are low in both these situations. When the donor and recipient are of the same species, i.e., human to human or mouse to mouse, that is an allogeneic (aloe-jenick) skin graft. A xenogenic (zeeno-jenick) skin graft is one in which the donor and recipient are of different species, so a human receiving skin from a pig. Both allogeneic and xenogeneic grafts have a higher risk of rejection, in which the immune system recognizes the graft as foreign and creates antibodies against it, which attacks and destroys the graft.