Autoimmunity: A misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
Autoimmunity is present to some extent in everyone and is usually harmless. However, autoimmunity can cause a broad range of human illnesses, known collectively as autoimmune diseases. Autoimmune diseases occur when there is progression from benign autoimmunity to pathogenic autoimmunity. This progression is determined by genetic influences as well as environmental triggers.
Autoimmunity is evidenced by the presence of autoantibodies (antibodies directed against the person who produced them) and T cells that are reactive with host antigens.
Autoinnoculation: Inoculation of a microorganism obtained by contact with a lesion on one’s own body, producing a secondary infection. This can happen, for example, with a fresh smallpox vaccination if the person who has been vaccinated touches it and transfers the virus to a scrape on their body.
Autologous: In blood transfusion and transplantation, a situation in which the donor and recipient are the same person. Patients scheduled for non-emergency surgery may be autologous donors by donating blood for themselves that will be stored until the surgery. An autologous graft is a graft (such as a graft of skin) that is provided for […]
- Autologous blood donation
Autologous blood donation: Giving blood to yourself. For example, patients scheduled for non-emergency surgery may be eligible to donate blood for themselves that will be stored until the surgical procedure. During the period of “storage” the body is making more blood. This donation is suggested in anticipation of a surgical procedure where significant blood loss […]
Autolysis: The enzymatic digestion of cells by enzymes present within them. The cells most susceptible to autolysis tend to be dying or dead cells. Pronounced aw-tol’i-sis.
- Automated external defibrillator
Automated external defibrillator: A device that automatically analyzes the heart rhythm and that’if it detects a problem that may respond to an electrical shock’delivers a shock to restore a normal heart rhythm. Thanks to their small size and ease of use, AEDs have been installed in many settings (such as schools and airports), and serve […]