cold agglutinin

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agglutinin

 [ah-gloo´tĭ-nin]
any substance causing agglutination (clumping together) of cells, particularly a specific antibody formed in the blood in response to the presence of an invading agent. Agglutinins are proteins (immunoglobulins) and function as part of the immune mechanism of the body. When the invading agents that bring about the production of agglutinins are bacteria, the agglutinins produced bring about agglutination of the bacterial cells.

Erythrocytes also may agglutinate when agglutinins are formed in response to the entrance of noncompatible blood cells into the bloodstream. A transfusion reaction is an example of the result of agglutination of blood cells brought about by agglutinins produced in the recipient's blood in response to incompatible or foreign cells (the donor's blood). Anti-Rh agglutinins are produced in cases of Rh incompatibility and can result in a condition known as erythroblastosis fetalis when the maternal blood is Rh negative and the fetal blood is Rh positive. (See also rh factor.)
cold agglutinin antibody that agglutinates erythrocytes or bacteria more efficiently at temperatures below 37°C than at 37°C.
group agglutinin one that has a specific action on certain organisms, but will agglutinate other species as well.
H agglutinin one that is specific for flagellar antigens of the motile strain of an organism.
immune agglutinin a specific agglutinin found in the blood after recovery from the disease or injection of the microorganism.
incomplete agglutinin one that at appropriate concentrations fails to agglutinate the homologous antigen.
O agglutinin one specific for somatic antigens of a microorganism.
platelet agglutinin an antibody capable of agglutinating platelets; these may be associated with a variety of disorders, with and without frank thrombocytopenia.
warm agglutinin an incomplete antibody that sensitizes and reacts optimally with erythrocytes at 37°C.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

cold ag·glu·ti·nin

an antibody that reacts more efficiently at temperatures lower than 37°C.
Farlex Partner Medical Dictionary © Farlex 2012

cold agglutinin

Any of the IgM antibodies that agglutinate at <32ºC and react with blood groups I and i, which are often present in atypical pneumonia caused by Mycoplasma pneumoniae. Cold agglutinins cause clumping of red cells when the extremities are cooled, causing Raynaud phenomenon.

Specimen
Serum.
 
Ref range
Titer < 32.
 
Method
RBC agglutination.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

cold ag·glu·ti·nin

(kōld ă-glū'ti-nin)
An antibody that reacts more efficiently at temperatures below 37°C.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

cold agglutinin

A substance found in blood serum that causes red blood cells to clump together (agglutination) if the blood is kept at low temperatures.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Plasmapheresis in a child with cold antibody autoimmune hemolytic anemia: Case report.
This hints at a possibility of a form of K2EDTA-related, cold antibody of IgM type in the patient's serum.
Cold antibody hemolytic anemia (CAHA) is classified as primary (idiopathic) or secondary.
In cold antibody AIHA, avoidance from cold and therapeutic plasma exchange are recommended as the first-line treatment and rituximab is recommended as the second-line treatment (3).
Direct Antiglobulin Test Antiglobulin Test 1 Y K1 2 Y Positive for autoantibody 3 N Lea 4 Y History of DAT positivity Fya and autoantibody (autoantibody) 5 Y Positive for passive Negative anti-D 6 Y History of DAT positivity Negative (autoantibody) 7 N Positive for passive Passive anti-D and anti-D cold antibody 8 N Lea 9 Y Lea 10 N C 11 N D, E 12 N Positive for autoantibody Anti-E, DHTR vs DSTR discovered 13 N D 14 N K1 15 N Cold antibody, roleaux 16 Y History of DAT positivity Negative (autoantibody) 17 Y History of DAT positivity Negative (passive anti-D and autoantibody) 18 Y Positive for autoantibody E, C, Fyb, and autoantibody 19 N K1, S 20 Y Leb 21 Y Positive for passive D anti-D 22 Y D 23 N D due to passive anti-D Hemolytic Blood Case Potential?