Cold agglutinins are directly against which of the following RBC antigens?
Two major types of "cold antibody" may produce autoimmune hemolytic anemia. Cold agglutinins, which directly agglutinate RBCs, mediate cold agglutinin disease. The Donath-Landsteiner autoantibody, which is not an agglutinin but a potent hemolysin, mediates paroxysmal cold hemoglobinuria. - Cold agglutinin disease : In current usage, cold agglutinin disease peains to patients with chronic AHA in which the autoantibody directly agglutinates human RBCs at temperatures below body temperature, maximally at 0 to 5degC. IgM Ab against I Antigen of RBC. Attaches at cold temperatures resulting in clumping/ agglutination - Acrocyanosis Extravascular hemolysis is seen. - Cold Hemolysin type : The Donath-Landsteiner antibody is responsible for complement-mediated hemolysis in paroxysmal cold hemo-globinuria, a rare form of AHA in adults. The disorder is characterized by recurrent episodes of massive hemolysis following cold exposure. IgG Ab against P Antigen of RBC. Ab binds at 40 C ,complement system is activated at 370C Causes intravascular hemolysis.
P antigen
I antigen
Le antigen
Rh antigen
Hemolytic Anemias: Basic concepts and classification