Serum sickness proteins to form immune complexes. These complexes precipitate, enter the walls of blood vessels, and activate the complement cascade, initiating an inflammatory response and consuming much of the available complement component 3 (C3). The result is a leukocytoclastic vasculitis. This results in hypocomplementemia, a low C3 level in serum. They can also cause more reactions resulting in typical symptoms of serum sickness. Serum sickness can be developed as a result of exposure to antibodies derived from animals. These sera or antitoxins are generally administered to prevent or treat an infection or envenomation. Some of the drugs associated with serum sickness
Blood transfusion Blood transfusion Blood transfusion is generally the process of receiving blood or blood products into one's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors, and platelets. Red blood cells contain hemoglobin and increase iron levels by improving the amount of oxygen found in the body. White blood cells, are not commonly used during transfusion but are related to the immune system and to fight infections.