serum sickness definition of serum sickness in the Free Online Encyclopedia.

serum sickness, hypersensitive response that occurs after injection of a large amount of foreign protein. The condition is named for the serum taken from horses or other animals immunized against a particular disease, e.g., tetanus or diphtheria. Such serum, which contains antibodies antibody, protein produced by the immune system (see immunity ) in response to the presence in the body of antigens: foreign proteins or polysaccharides such as bacteria, bacterial toxins , viruses, or other cells or proteins.
..... Click the link for more information. against the disease toxins toxin, poison produced by living organisms. Toxins are classified as either exotoxins or endotoxins. Exotoxins are a diverse group of soluble proteins released into the surrounding tissue by living bacterial cells.
..... Click the link for more information. , was formerly widely used to temporarily immunize humans. However, the antibodies from the animal serum are also foreign proteins that can act as antigens when injected into humans. The recipient's body responds by producing, within 8 to 12 days, antibodies that react against the animal serum proteins; the reaction causes injury to blood vessel walls and such allergic symptoms as rash, itching, and swelling of the lymph nodes. Fever, joint pain, spleen enlargement, and even shock may occur (see allergy allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-causing substances, can be airborne substances (e.g.
..... Click the link for more information. ; hypersensitivity hypersensitivity, heightened response in a body tissue to an antigen or foreign substance. The body normally responds to an antigen by producing specific antibodies against it. The antibodies impart immunity for any later exposure to that antigen.
..... Click the link for more information. ). The reaction subsides as continued production of antibodies removes foreign protein from circulation. A person who has once had a serum injection is sensitized to the serum antigens, and a second injection can bring on the acute reactions typical of anaphylaxis anaphylaxis (ăn'əfəlăk`sĭs)
..... Click the link for more information. . Today, serum preparations are rarely used. Instead, inoculations of tetanus and diphtheria toxoids toxoid, protein toxin treated by heat or chemicals so that its poisonous property is destroyed but its capacity to stimulate the formation of toxin antibodies , or antitoxins , remains.
..... Click the link for more information. are given in childhood; they confer active immunity against those diseases. Serum sickness may occur in response to proteins other than those found in serum.

serum sickness [′sir·əm ‚sik·nəs]

(medicine)

A syndrome manifested in 8-12 days after the administration of serum by an urticarial rash, edema, enlargement of lymph nodes, arthralgia, and fever.