ABO Blood Groups Flashcards
Describe the biochemistry of ABO blood groups
carbs/receptors for
can be what shapes
carbs on outside serve as receptors for macrophages to recognize
can be branchy/straight arranged in a format means its type 2
What type can be on the outside of the cell and be transferrred into ABO ag
Type 2 can
Describe the ABO gene
codes for..
codes for transferase that adds a sugar to the end of the H subgroup or RBC
What happens if the ABO stop codon is in gene?
no transferase is created and no sugar is added, pt is type O
What does A transferase add?
N-Acetyl-galactose
What does B transferase add?
Galactose
What chromosome is ABO blood groups?
Chromosome 9
Anti-A Anti-B. Anti-A,B
+. - +
Type A
Anti-A Anti-B. Anti-A,B
- + +
Type B
Anti-A Anti-B. Anti-A,B
+ + +
AB type
Anti-A Anti-B. Anti-A,B
- - -
O type
Describe inheritence
If genotype is unknown
if the genotype of an offspring is unknown, phenotype expression in offspring give clues
the offspring of a mother who is AB and a father who is B will have what chance of being what type?
50% chance of being type B
Describe A/B genes
on same what?
co-dominant allels on the same chromosome where O is the recessive trait
Describe medellian %
apply to genotypic inheritence of the ABO types
familial inh. map can help guess at genotype using phenotype
Blood types: A,B,AB,O
Describe the US population frequency
expressions in different world locations
selection pressures/probably pathogen driven
Describe the greater prevelence of blood types in ethnicities
A - north/central europe
B - central asia
O - native americans
What is the most common blood type
O
Describe H genes
codes a ….
codes a fucosyl transferase that adds a fucose to the outer sugar of a type 1/2 precursor chain
What chromosome are H substances and what is their gene
Chromosome 19
Fut gene
T/F the more H substance that is transferrred to an A/B ag, the more detectable it is
false, the less detectable it is
List the common blood types with >
O>A2>B>A2B>A1>A1B
Describe Bombay briefly
absense
still have
can do what but cant do?
absense of H ag
still have ABO genes
they can transfer but dont exhibit genes themselves
What does Autosomal recessive Bombay mean
what genotype
means what cant be formed?
mutation
hh, genotype produces no H ag meaning no ABO ag can be formed on rbc (most likely mutation of FUT1 gene that silences the gene)
How do Bombays appear serologically
fail to rxn w?
appear as type O, fail to react with Ulex Eruopaeus (H lectin)
Briefly describe parabombay phenotypes
rbc devoid…
what mutation
all H ag …
rbcs completley devoid of H ag, and still exhibit small amount of A/B ag
FUT1 mutation - fucosyt with low activity
All H ag available is converted to A or B by the normal acting A/B OR FUT2 FUNCTIONS
Describe the biochem of H substances
as pt matures
A/B can add..
as pt matures, type2 subst can become more branchy
The A/B can add their sugars to any H substance on the cell
Describe fewer branching H sub
pt may appear….
subgroup…
if fewer branching H sub are transferred to A/B, the pt may appear as a weaker version of the blood type
Subgroup is more common in AB blood group
Describe if only one H substance is transferred
pt sees a ….
may appear…
the pt sees a transferred other form, it may appear as foreign and ab can form
Describe the A1 phenotype
dont recognize any version of A as foreign
+ with Anti-A/lectin (branched)
Describe the A2 phenotype
+ with = with
+ with Anti-A
- w/ Anti-A/Lectin
Briefly describe the subgroup A
quant. less….
testing
may make?
subgroup people have quant. less Ag converted from H substance
serologic
may make an Ab against the most common
expression of Ag
T/F A subgroups are more common than B
T
A3
Mixed field
Aend
<10% rbcs weak agg
Ax
weak agg, W/ anti-A,b ONLY
Am
no agg/ A in saliva
Ay
no agg/ small A in saliva
Ael
No agg/ only H sub in saliva
A1 Anti-A Anti-B. A1 cell B cell
+4. +3 0 0 4+
A1
A1 Anti-A Anti-B. A1 cell B cell
0 3+ 0 1+ 4+
A2
A1 Anti-A Anti-B. A1 cell B cell
0 0 4+ 4+
Bombay subgroup
Describe B supgroups
NO SUCH THING AS B2
B3- mixed rxn
Bx - weak rxn …etc
Describe the lectins and what they match up with
D. Biflorus - A1
B. simplificolia - B
U. Europaeus - H
AB Anomalies
Describe Cis Ab
what on same?
Can pass?
Rare?
A and B transferase inherited on same chromosome
can pass AB type w/ O mate
rare splicing anomaly
B(A) pt
can do?
vary of?
what anti
transferase is able to do both, prefers to transfer galactose
genetic variation of B gene
Polyclonal antiseria
Aquired B pt
what group
cancer
what obs
bacteria?
what anti?
group A1
cancer of colon/rectum
intestinal obstruction
Gram neg septic
Acidified antisera
Aquired B type can be from e.coli how does it do this?
via deacetylating enzyme that affects the A sugar
Anti-A Anti-B. Anti-A,B
+4 +1 +4
A(B)?
Why is the ABO system important
only system that the reciprocle Ab are consistent and predictable that have never been exposed to other human Ag (babies get them at 4 mos ish)
What makes up the forwards type
Reverse?
Anti-A, Anti-B, Anti-A,B
A1 cells, B cells
Anti-A Anti-B. Anti-A,B
+4 0 +4
A1 B cells
0 +4
A
Anti-A Anti-B. Anti-A,B
0 +4 +4
A1 B cells
4+ 0
B
Anti-A Anti-B. Anti-A,B
0 0 0
A1 B cells
+4 +4
O
Anti-A Anti-B. Anti-A,B
+4 +4 +4
A1 B cells
0 0
AB
