Polyagglutination Flashcards
What is polyagglutination?
Agglutination caused by ABO compatible sera due to altered RBC membrane that exposes crytantigens. Polyagglutination does not occur with cord blood sera
What are polyagglutinins?
Naturally occurring IgM antibodies found in most adult sera such as anti-T and anti-Tk
How is polyagglutination detected?
Rarely seen with the use of monoclonal reagents.
Not detected in the crossmatch because it is red cell problem (unless donor is polyagglutinable; rare)
Clinical condition suspected when patient is hemolyzing
DAT and Auto are often negative
What conditions is associated with T activation?
T activation is found in patients with CARCINOMA, malignant breast tissue, septicemia, GI dissorders, and wound infections
Often caused by Pneumococci, Clostridium perfringes, Vibro, and influenza virus
More common in children
May be an early marker for HUS
How does T activation occur?
bacteria produce neuraminidase that cleaves both NANA from SGP and exposes T receptor.
M, N, and Pr antigens are lost
Can create artificial T cells with neuraminidase
Enzyme treatment removes MN so anti-T will not react
What is Th polyagglutination?
Early stage of T activation caused by neurominidase
Found in patients with septicemia assoc. with E. coli, Clostridia, Bacteroides, and Proteus
How does Tk poly agglutination occur?
Bacteria that produce endo-beta-galactosidase remove galactose residues exposing GluNAc on paraglobloside. ↓ ABO, Lewis, Ii, and P1.
Acquired B is often seen w Tk.
Normal paraglobside = Gal-GluGal-Gal-Glc-Cer
What lectins will react with T polyagglutination?
Glycine soja and Arachis hypogaea
What lectins will react with Th polyagglutination?
Arachis hypogaea
What lectins will react with Tk polyagglutination?
Arachis hypogaea and Griffonia simplicifolia
What causes Tk polyagglutination?
Caused by Bacteroides fragilis, Aspergilus niger, and C. albicans
Assoc. w/ GI infection, septicemia and wound inf.
What is VA polyagglutination?
Possibly caused by microbial infection. Depressed H antigens may be caused by a a-fucosidase. Assoc. w/ hemolytic anemia.
What is Tx polyagglutination?
Rare; 1st described in children with pneumococcal infections
What is acquired B?
A1 cells with B like activity due to bacterial deacetylation of the A antigen. Acetyl group removed from GalNAc and galactosamine remains that is similar to the B antigen.
What causes Tn polyagglutination?
An acquired somatic mutation on X chromosome leads to poor synthesis of sialic residues on the MN SGP. M/N reduced.
Lacks B-3-D galactosyltransferase. No terminal NANA and Gal results in exposure of GalNAc that human anti-A will react with.