P1PK and GLOB Flashcards
What antigens are in the P1PK BGS?
P1 - polymorphic 80% white = P1+
Pk - high freq
NOR - high freq
What antigens are in the Globoside BGS?
P = high freq (99.9%)
Uses different enzyme to add sugar to chain
What antigens are in the Globoside Collection?
LKE and PX2 are both high frequency
P1 soluble antigen is found in?
Pigeon Egg Whites
Hydatid Cyst Fluid
liver flukes
Used in neutralization techniques
P1 and PK antigens are located on what cells?
Lymphs, Granulocytes, Mono’s, and PLT’s
What causes P2 phenotype?
P2 is caused by 2 amino acid change to A4GALT enzyme = unable to form P1 from paragloboside chains
P2 people lack P1 and can make anti-P1
How do you determine if they are P2 phenotype?
If patient types as P1 negative must type person for P antigen. Should type as P positive, or they may be a rare P2K or p (null) phenotype
Antigens present in P1 phenotype?
P1, P, and Pk (Pk may type as negative because P is formed from Pk)
Antigens present in P2 phenotype?
P and Pk (Pk may type as negative because P is formed from Pk)
Make anti-P1
P1k
P negative = Can make anti-P
Have P1 and Pk
P2K
Pk only present
Can make anti-P1 and anti-P
p
Null - no P, P1, or Pk
Can make Anti-PP1PK (Anti-Tja)
Frequency of P1 phenotype?
Whites = 80% Vietnamese/cambodians = 20%
Frequency of P2 phenotype?
Whites = 20% Vietnamese/cambodians = 80%
Frequency of P1k, P2k. and p?
Extremely rare
p seen in northern Ohio amish people
How is P1 antigen formed?
A4GALT adds a galactose on to paragloboside chain
Paragloboside is precursor for Type 2 H chains and PX2
How is Pk antigen formed?
A4GALT enzyme adds galactose to Lactosylceramide
How is P antigen formed?
P antigen is formed from Pk
B3GALNT-1 adds GalNAc to Pk > P antigen
How is NOR antigen formed?
Formed from P antigen
A4GALT enzyme adds galactose to P antigen
How is LKE antigen formed?
Formed from P antigen
A4GALT enzyme adds galactose and sialic acid is added to form LKE
Characteristics of P1 antigen
Weaker on cord cells until 10 years of age
Antigen varies in strength and is weaker on older cells
Enzymes enhance reactivity
Not destroyed by Papain, Ficin, EGA, DTT, Chloroquine
Allo anti-P1
Found in P2 people
IgM naturally occuring
Reacts best at RT or below 25C - Cold saline agglutin
Give XM compatible blood
Characteristics of Pk antigen
Expressed on cord cells Expressed on cells except p null cells - Weak on P1 and P2 because hidden High frequency antigen May provide protection against HIV
Anti-PP1Pk
Seen with Anti-Pk (can adsorb out) Formed in p null individuals IgM and a mixture of IgG/IgM Wide terminal range-reacts at RT, 37C and AHG Binds complement Naturally occurring POTENT hemolysin Causes abortions, TRN RXN, and HDFN
NOR antigen
Low frequency part of P1PK BGS
NOR+ cells are agglutinated by most adult sera so its thought to be related to polyagglutination
Enzyme enhances
Anti-NOR is IgM
How is NOR antigen formed?
Galactose added to GLoboside or P antigen
Single amino acid change to A4GALT responsible
Where is P antigen found?
Found in RBC, lymph, mono’s, and placenta
Expressed on Cord cells
What populations are P negative found in?
Negative found in Scandinavians, Isrealis, Amish, Finns, Arabs
How is P antigen formed?
P is formed by B3GALNT adding a GalNAc to Pk
Auto anti-P
Causes PCH
Powerful IgG Biphasic hemolysin, complement binding
Positive Donath-Landsteiner test but routine testing is negative. DAT is +/-
More common in children
What is PCH?
Antibody/antigen complexes auto anti-P are formed at lower temps in peripheral blood and when temp is raised complement is activated and hemolysis occurs
Allo anti-P
Rare antibody
Potent hemolysin with wide thermal range
may cause spontaneous abortion
Decreased P1 antigen is seen in…
In(Lu) phenotype = reduced expression of antigens in the Lutheran system, P1, Inb, and AnWj antigens
LKE antigen
Expression decreased in Secretors
LKE S+ = 80-90%
LKE W+ = 10-20%
1-2% are LKE negative (P1k, P2K, p)
How is LKE antigen formed?
PK > P > + sialic acid = LUKE antigen
Anti-LKE
Rare
IgM with some complement binding
not clinically significant
PX2 antigen
High freq
Not found in P1k or P2k
Highly expressed in p individuals
Anti-PX2
IgG or mixture of IgG/IgM
Naturally occurring
Enhanced by enzymes
What disease is Pk antigen associated with?
Receptor for shiga toxin causing shigella dysentery
What disease is P antigen associated with?
Receptor for parvovirus
