I, i Antibodies Flashcards
What two disease states is Anti-I associated with?
Cold agglutinin disease and Mycoplasma pneumoniae infections
What kind of antibody is Anti-I?
IgM cold antibody
What type of cells does Anti-I react with?
All adult cells (except rare i adult)
In regards to Anti-I, what might make having this antibody challenging in an antibody screen?
Anti-I may mask clinically significant alloantibodies
How do you remove Anti-I so that you can detect underlying antibodies?
Autoadsorption or allogenic adsorption
RESt adsorption
Using IgG AHG instead of polyspecific AHG
Prewarming – have to use this with caution because this can result in decreased activity of some clinically significant antibodies or cause weak antibodies to be missed
Will you find I-antigen on cord cells?
No -
I antigen is absent or weak on cord cells.
What happens to antigen i as an infant matures?
i antigen converts into I as infant matures due to branching of carbohydrate chains
What i/I antigens do infants have?
i positive, I negative
What i/I antigens do ADULTS have?
i negative, I positive
How can you differentiate a person who has PCH (Paroxysmal Cold Hemoglobinuria) from someone who has cold agglutinin disease?
PCH: Anti-P specificity; Donath Landsteiner test diagnoses PCH and would be positive
Cold agglutinin disease: Anti-I. POSITIVE DAT. Agglutination on blood smear.
Cold symptoms happen seasonally in cold months. Donath Landsteiner test would be negative.
Cold agglutinin disease is often associated with which antibody?
Anti-I
What antibody is associated with infectious mononucleosis?
Anti-i
Does Anti-I cause HDFN?
No. It is an auto-antibody that is found in virtually all sera. It is IgM and naturally occurring and not clinically significant in HDFN.
Which adsorption technique removes cold (IgM) antibodies, particularly anti-I specificities?
RESt (Rabbit erythrocyte stroma)
RESt removes cold (IgM) antibodies, particularly anti-I specificities. However, it may adsorb anti-B and other IgM antibodies.
Which antigen group is closely related to the ABO antigens on the red cell membrane?
I and i
The I and i antigens exist on the precursor A, B, and H oligosaccharide chains at a position closer to the red cell membrane. The I antigen is associated with branched chains, and the i antigen is associated with linear chains.
