BB - Day 2 Flashcards by Kevin Tran

Define “naturally occurring” antibodies. What two types of antibodies are considered naturally occurring?

Targets antigens on RBCs due to similarity to a naturally occurring target in nature
-unknown mechanism, possibly gut bacteria

anti-A and anti-B

How well did you know this?

Not at all

Perfectly

ABO - which phenotype is the rarest?

How well did you know this?

Not at all

Perfectly

Naturally occurring antibodies - can they cross the placenta? Why or why not?

No - predominantly IgM

-except anti-A,B, which is IgG

How well did you know this?

Not at all

Perfectly

ABO - which phenotype is the universal RBC donor? Universal plasma donor? Universal recipient?

RBC donor = O negative
-can only take other O blood

Plasma donor = AB
-no antibodies against A or B antigens

Recipient = AB

How well did you know this?

Not at all

Perfectly

Can newborns be forward typed and back typed?

Forward = yes

Back = no, only maternal antibodies present at birth
-wait >6 months

How well did you know this?

Not at all

Perfectly

At what temperature do ABO antibodies react best?

Room temperature or colder

How well did you know this?

Not at all

Perfectly

The immune form of ABO antibodies are produced during (2)…

Transfusions

Pregnancy

-these events expose patients to foreign blood cells

How well did you know this?

Not at all

Perfectly

Anti-A,B antibody is produced only by this ABO phenotype

How well did you know this?

Not at all

Perfectly

Which ABO antibody(ies) can frequently cross the placenta? Why?

Mostly anti-A,B since they are predominantly IgG

How well did you know this?

Not at all

Perfectly

A and B antigens are composed of… Their precursor is…

Carbohydrates

H antigen

How well did you know this?

Not at all

Perfectly

Which gene codes for H antigen?

H gene

independent of ABO genes
H is dominant; one copy can make H antigen (Hh)

How well did you know this?

Not at all

Perfectly

A person that’s hh phenotype can’t make what antigens… Another name for the hh phenotype

H antigen, A antigen, and B antigen
-H antigen is a precursor to A and B; cannot make H = cannot make A or B

Bombay

How well did you know this?

Not at all

Perfectly

A person’s H precursor levels are highest in this ABO phenotype. Why?

No A or B antigens on O cells, so a lot of residual H

How well did you know this?

Not at all

Perfectly

A Bombay patient should receive a blood transfusion from another person with this blood type… Why?

Bombay

Bombay patients make anti-H against all other ABO groups

anti-H is naturally occurring
forward = A and B negative
reverse = anti-A1, anti-B, anti-O positive

How well did you know this?

Not at all

Perfectly

Besides RBCs, ABO antigens are also found on… What is this significance?

Endothelium, kidney, heart, bowel, pancreas, lungs

Can cause extravascular hemolysis

How well did you know this?

Not at all

Perfectly

A person is considered a secretor when they can secrete these antigens in all bodily secretions… The secretor system involves which two blood group systems?

A, B, H

ABO and Lewis

How well did you know this?

Not at all

Perfectly

What percent of the US population are secretors?

80%

How well did you know this?

Not at all

Perfectly

To be a secretor, a person must have one of these genotypes… People that are non-secretors have this genotype…

SeSe or Sese (dominant phenotype)

sese

How well did you know this?

Not at all

Perfectly

A1 vs A2 - which is more common?

Study These Flashcards

A1 = “normal” A

A1 reacts with which anti-A antibodies? A2 reacts with which anti-A antibodies?

Study These Flashcards

A1 = anti-A, anti-A1
-A1 cells have A and A1 antigens

A2 = anti-A only
-A2 cells have A antigens only

Dolichos biflorus will agglutinate this cell

Study These Flashcards

A1 cells

anti-A1 lectin

A1 and A2 can be distinguished via forward or reverse typing?

Study These Flashcards

Reverse typing only

Ulex europaeus will agglutinate A1 or A2 cells? Why?

Study These Flashcards

A2 cells
-U. europaeus = anti-H lectin

A2 has more precursor H than A1
-incomplete conversion to A antigen = more remaining precursor H

anti-H antibody - what class of antibodies?

Study These Flashcards

IgM - reacts best under room temp, can bind complement

-similar to other ABO antibodies

What blood should be given to A2 patients?

A2 or O | -A2 patients make anti-B and anti-A1 antibodies, but not anti-A antibodies

anti-H antibody reacts strongest and weakest with these ABO phenotypes

Strongest = O (high precursor H) Weakest = A1B (low precursor H) -suspect anti-H antibody if O cells are reactive but A cells are not

General rule in the lab - should we drop cells first or solution first?

Drop solution first, cells second - so you know you've already added it - so you don't contaminate reagents

Why are A1 cells normally used for reverse typing?

A1 cells contain high number of A antigens

If there's a discrepancy and the reverse typing does not match the forward typing what can we do with our test tubes?

Let samples sit for 15 mins at room temperature, then re-spin tubes -weak positive for reverse typing not good enough

Depressed antibody production affects forward or reverse typing?

Reverse - seen in newborns, elderly, leukemias - lower or nonexistent antibody production

What is the "acquired B" phenomena? How is it treated?

Bacterial enzymes convert A antigen to B antigen, so patient's anti-B antibodies attack cells Acidify patient's sera

Where can one find Wharton's jelly?

On baby's cord blood only - mucopolysaccharide that sticks to RBCs - need multiple washing to get rid of

A2 patients show a reverse typing that looks like... Why?

O A2 patient has anti-B and some anti-A1 antibodies naturally because A2 cells have A antigens but no A1 antigens -A1 patients have both A antigen and A1 antigen

What is the name of the A antigen sugar? What is the name of the B antigen sugar?

N-acetylgalactosamine D-galactose

HDFN is caused primarily by the antigen group

Rh - what are the 5 major antigens?

D, C, c, E, e

What does little 'd' signify in the Rh group?

Lack of D antigen | -little 'd' is NOT an antigen

Are homozygous or heterozygous antigens stronger?

Homozygous = more binding sites

What should we do if our anti-D and Rh control tubes are both negative?

Do a weak D test | -15 min at 37C, 3x wash, AHG

Weak D is caused by (3)...

Genetics - person makes fewer D antigen C Trans - allele carrying D trans to allele carry C -Dce/dCe Partial D (mosaic D) - missing piece of the antigen

Rh antibodies are what class of immunoglobulins? When are they produced?

IgG After exposure due to transfusion or pregnancy -not naturally occurring

What temperature do Rh antibodies react optimally?

37C - anti-D = IgG, reacts best at 37C - that's why we heat 37C for 15 min in weak D test

Do Rh antibodies cause intravascular or extravascular hemolysis? Why?

Extravascular only Rh CANNOT bind complement

Can Rh antibodies cross the placenta? Why?

Yes They are IgG

Rh-negative mothers are automatically given ___ at the 28th week of pregnancy to prevent ___

RhIg (RhoGAM) - an anti-D antibody Sensitization to Rh-positive baby, making anti-D antibodies - can make IgGs that cross placenta and attack baby's cells, causing extravascular hemolysis (HDFN) - given even if we don't know baby's Rh status yet

Is Cw expressed on big C or little c?

Both - allele on C/c locus - low frequency antigen

Which 2 Weiner phenotypes are the rarest?

Rz and r^y

BB - Day 2 Flashcards

(47 cards)