Polyagglutination Flashcards
Polyagglutination
Red Blood Cells that agglutinate in the presence of virtually all adult human serum. An RBC abnormality not a plasma abnormality. consequence of a change from normal that occurs on the surface of the red cell. Not related to blood group specificity \1024797639\
Cryptantigen
crypt=hidden, exposeure of an antigen that is normally hidden (T, Th Tk, Tx)
Exposure of Cryptantigen
Happens most often as a result of bacterial infection. Bacterial enzymes remove carbohydrates normally present exposing new antigens. Most normal human adults have naturally occurring IgM that are reactive with cryptantigens. (T, Th Tk, Tx)
Microbial Polyagglutination
Bacterial enzymes remove carbohydrates normally present exposing new antigens
Non-Microbial Polyagglutination
Abnormal synthesis of RBC membrane structures (Tn, Cad, HEMPAS, Hemoglobin M (Hyde Park) Tr
Glycophorin structure
Sugars are added onto the amino acids
T polyagglutination
“T activation” Cleaving Enzyme=neurominidase. Bacteria or viruses infecting the individual produce the enzyme and cleaves NEuNac and therefore decreases the amount of sialic acid
Most common bacteria associated with T activation
Clostridium perfringes, Vibrio Cholorae, streptococcous pneumoniae
Most common type of polyagglutination
T activation
Cad
Inherited autosomal dominant. Cad+ cells strong expression of Sda also called Super Sda. Resistant to plasmoidum falciparum, react strongly with anti-Sda which is naturally occurring in most human sera.
Th Polyagglutination
Low level/early/mild T activation- same biochemical mechanism as T activation- neuraminidase cleaves NeuNac- not an effective removal therefore normal levels of sialic acid are present. May be a pre-leukemic marker. Lacking B-3-D-Galactosyltransferase.
Tx and VA polyagglutination
mechanisms are not fully understood but know the terms
Tk Polyagglutionation
Cleaving enzyme= Beta-galactosidase (endo or exo)- cleaves the Gal-GlcNac linkages found primarily on paragloboside structures and ABH/Ii precursors. Decreased expression of ABH, Lewis, Ii and P1 antigens
Acquired B Polyagglutination
Cleaving enzyme=deacetylase- causes deacaetylation of group A immunodominant sugar- leaves galactosamine, cross reactivity that makes the A antigen appear like a B antigen in tube testing
Tn polyagglutination
Persistent mixed field polyagglutination- persisitent= due to somatic mutation of hematopoietic stem cells . Tn antigen is found on the same structures as the T antigen (Glycophorin A and B) Mutated clone of cells lack beta-3-galactosyltransferase. MF is due to two different cell populations 1 being mutant clone 2. being normal
Chromosomal mutation of Tn polyagglutionation
Gene carried on the X chromosome
HEMPAS
Hereditary Erythroblastic Multinuclearity witeh a Positive Acidified Serum Test . Inherited autosommal recessive, RBCs have a second membrane internal and parallel to the external membrane, The RBCs react with Anti-I anti-i and Glysine soja
Ham’s test
Positive Acidified Serum Test, used in diagnosis of PNH. Placing RBCs in a mild acid-hemolysis (increased RBC fragility) indicates PNH or congenital dyserythropoietic anemia (HEMPAS), not widely used anymore.
Tr Polyagglutination
Mmebrane proteins are not glycosylated, inherited autosomal recessive
Hemoglobin M-Park Polyagglutination
Reported in a south african family of mixed race, due to 2 unrelated RBC membrane abnormalities
Today vs. Historical detection of polyagglutination
Used to use human derived serum, abo discrepancy, positive dat and minor crossmatch. Today: monclonal antisera lack the naturaly occurring polyagglutinins that are found in adult human sera.
Today vs. Historical detection of polyagglutination
Used to use human derived serum, abo discrepancy, positive dat and minor crossmatch. Today: monclonal antisera lack the naturaly occurring polyagglutinins that are found in adult human sera. May be detected with IS crossmatch, same donor incompatibilities or MF due to Tn polyagglutination.
How are different types of polyagglutination classified in lab tests
Through the use of Lectins,
Polybrene vs. Glycine Soja
Polybrene- sialic acid deficient RBCs will not aggregate. Glycine Soja- sialic acid deficient RBCs strongly react
Enzyme treatment of RBCs with papain or ficin
Increased reactivity Tk, Cad. Decreased reactivity Tn and Th. No change- T, VA, HEMPAS
Lectins
Proteins found in plants and seeds, invertebrate animals and lower vertebrates. Reactivity depends on the terminal of subterminal sugars and their 3d configuration
Transfusion practices for polyagglutination
Cellular products: cell saver or Saline washed products. Plasma- avoidance!! Plama from a suitable donor T/Tn deficient Needs a minoR crossmatch- Donor plasma and recipient RBCs
Tn cells react with what lectins?
Dolichos Bifloris, Glycine soja (max) Salvia sclarea, Salvia hominum Griffonica simplifica 1
Cad cells react with what lectins?
Dolichos Bifloris, Glycine Max, Salvia hominum
Tk cells react with what lectins?
(TAKITAKI) -Arachis Hypogaea, Griffonica simplifica II
T cells react with what lectins?
(TAG) arachis hypogaea, glycine soja
Th
(THA) Th- archais hypogaea
Cad+ with lectins
positive with salvia hominum and glycine soja (CADSG)
