MLS 4130 Blood Bank Exam 1

immune

Is IgG natural or immune?

IgG

Which class of antibodies is [most] clinically significant?

both

is IgM natural or immune?

-host response

-biochemical/physical characteristics of the immunogen

What are two factors that antibody production relies on?

-Size of molecule

-Complexity

-Physical conformation

-Charge

-Epitope accessibility

-Solubility

What are the biochemical and physical properties that affect antibody production? (6)

IgM

What class of Ig are ABO antibodies?

-blood transfusion

-pregnancy

What two ways would a patient develop alloantibodies to blood group antigens?

affinity

strength of a single antigen-antibody bond

avidity

binding strength of an antigen with antisera produced in an immunized individual

valency

number of antigen-binding sites on antibody molecule, or number of antibody binding sites on an antigen

decreases the zeta potential (negative charges) of RBCs

How does centrifugation enhance agglutination reactions?

the heavy chain of the FC region of human IgG

What portion of IgG does AHG have specificity for?

To visualize IgG reactions

What is the purpose of potentiators in agglutination reactions?

Protein Media that reduce the zeta potential of RBCs [by removing water between cells]

Albumin, Polyethylene glycol (PEG), PVP, and protamine are examples of what type of potentiators?

Low ionic strength media, increases antibody uptake and reduces incubation time

LISS or low salt media are examples of what type of potentiators?

AHG (Anti-human-globulin)

This potentiator cross-links sensitized cells for the DAT and IAT test and can detect IgM and IgG if incubated

22% albumin

This potentiator causes agglutination by adjusting zeta potential and requires 60 mins of incubation at 37C to detect IgG

LISS

This potentiator causes rapid uptake of antibody to RBC by reducing zeta potential and detects IgG after incubation at 37C for 15 mins

PEG

This potentiator removes excess water from between cells and can detect IgG after 15 mins incubation at 37C

Direct Antiglobulin Test (DAT)

This test detects in vivo RBC sensitization

Indirect Antiglobulin Test

This test detects in vitro sensitization of RBCs

IAT (Indirect antiglobulin test)

Which test is the antibody screening test?

-human IgG

-C3d

-C3b

What specificities does polyspecific AHG have?

IgG1 and IgG3 because they are more immunogenic

What classes of IgG must be incorporated in AHG?

-HDFN

-Hemolytic transfusion reaction

-Autoimmune hemolytic anemia

-Drug-induced hemolytic anemia

What are four conditions that can cause a positive DAT test.

-van de waals forces

-hydrophobic bonds

The intermolecular binding force of antibody-antigen reactions are attributed to what? (2)

The FC portion of the heavy chain

What portion of antibody structure does AHG have specificity for?

Antiglobulin test

Also known as the Coomb's test

Because infants do not create complement, it is only necessary to test for the presence of reactive antibodies

Why are monoclonal AHG be used for infant samples?

-compatibility testing

-RBC phenotyping

-titration of incomplete antibodies

What are the clinical applications of the IAT? (3)

True

ABO blood group inheritance is said to have codominant expression. True/False

amorph

A gene that does not appear to produce a detectable antigen; ex: group O gene

A1

If a patient's genotype is A1A2, what would their phenotype be?

-ABO

-Hh

-Se

ABH antigen formation results from the interaction of genes at which three loci?

Enzymes that add antigenic sugars to precursor substances on the surface of RBCs

What do glycosyltransferases do?

Individuals with the Se gene have ABO antigens ubound in their secretions

What is the significance of he Se gene?

α-2-L-fucosyltransferase

What is the product of transcription of the H gene?

L-fucose

Which sugar is associated H specificity (blood group O)

group O

Which ABO blood group has the highest concentration of H antigen?

A gene

Which gene codes for the production of α-3-N-acetylgalactosaminyltransfer-ase?

N-acetyl-D-galactosamine

What sugar is associated with group A?

group A

Which blood group has the highest conversion rate of H antigen to ABO group sugar? (810K-1.17M antigenic sites)

B gene

What gene codes for production of α-3-D-galactosyltransferase?

D-galactose

What sugar is associated with group B?

More B sites. The B enzyme is more efficient at competing for H substance that the A enzyme.

An individual phenotype AB will have more A antigenic sites, or B antigenic sites on their RBCs?

A blend of monoclonal anti-A, anti-B, and anti-A,B

What is polyclonal antisera?

used in identifying donor unit types, and is more effective at identifying weak A or B antigens

What is the purpose of anti-A,B

blue

What color is anti-A reagent

yellow

What color is anti-B reagent

Exposure to A-like and B-like antigens on bacteria prompt production of naturally occuring A and B antibodies

What is the postulated role of bacteria in ABO related antibodies?

Predominantly IgM, though can also be IgG

What is the predominant class of ABO antibodies (in vivo)?

at 3-6 months

When can A/B antibodies begin to be detected with titers in an infant?

maternal IgG antibodies have crossed the placenta

Why would there be discrepancies between the forward and reverse typing on a newborn?

between 5-10 years of age

When does peak antibody production occur over the course of human life?

refrigerating the reactions aids agglutination of IgM

What is one way to accelerate reverse type reactions with specimens from patients in advanced age?

45%

What percentage of the white population is type O

50%

What percentage of the black population is type O

40%

What percentage of the white population is type A?

26%

What percentage of the black population is type A?

11%

What percentage of the white population is type B?

20%

What percentage of the black population is type B?

4%

What percentage of the white population is type AB?

4%

What percentage of the black population is type AB?

Group O

What is the most common ABO blood group among the hispanic population (56%)?

A1 (converts almost all H substance)

Which is more efficient at converting H substance, A1 or A2?

true

Forward grouping reagent agglutinates both A1 and A2 phenotypes. True/False

Dolichos biflorus

What is the source of anti-A1 lectin?

A1

Lectin derived from dolichos biflorus will only react with which antigen?

Banderiaea simplicifolia

What is the source for group B lectin?

Ulex europaeus

What is the source of lectin that agglutinates H antigen?

Bombay

What phenotype lacks expression of both ABO and ABH antigens?

True

Anti-H found within individuals with Bombay blood type are often potent and react strongly at body temperature. True/False

Secretions, unbound to RBCs

Where are type 1 chains found?

blood group antigenic chains that are found in plasma and secretions

Where are type 1 chains found?

Type 2 antigenic chain

A terminal galactose attached to N-acetylglucosamine in beta 1-4 linkage describes what type of antigenic chain?

Type 1

A terminal galactose attached to N-acetylglucosamine in beta 1-3 linkage describes what type of antigenic chain?

Group I

Which discrepancy group is related to unexpected reverse reactions due to weakly reacting or missing antibodies?

-patient history

-incubate at 4C with an auto control and O cell controls

How would you resolve a group I discrepancy?

-newborns

-elderly

-leukemic/immunosuppressed

-agammaglobulinemia

-patients with diluted plasma

What categories of patients are prone to Group I discrepancies?

Group II

Which discrepancy group is associated with unexpected forward reactions?

Group II

What is the least common discrepancy group?

group II

"Acquired B" is an example of what group of discrepancy?

Group III

Discrepancies involving forward and reverse types that are caused by plasma abnormalities or proteins are part of which group?

-increased globulins

-increased fibrinogen

-plasma expanders (drugs)

-Wharton's jelly

What are the four common causes associated with Group III discrepancies?

-wash cells

-saline replacement technique

How would you resolve a group III discrepancy?

Group IV

What discrepancy group occurs between forward and reverse reactions due to miscellaneous problems?

Group IV

A discrepant reaction due to mixed cell populations from blood transfusions would be considered what category of discrepancy?

Group IV

Cold reactive auto -antibodies or unexpected ABO or non_ABO alloantibodies are examples of what category of discrepancy?

Rh antigens and corresponding antibodies

What accounts for the majority of unexpected antibodies encountered?

-pregnancy

-transfusion

What causes Rh antibodies to form?

FALSE. Rh antibodies are immune and only created as a result of exposure to the antigen.

Rh antibodies are natural antibodies. True/False

International society of blood transfusion; created to standardize blood group system nomenclature

What is ISBT?

The blood group system

What do the first three digits of standardized nomenclature represent?

The specific antigen

What do the last three numbers of standardized nomenclature represent?

80%

What percentage of people D negative individuals who are exposed to D antigen are expected to develop immune anti-D?

Fisher-Race

This theory posits that D, C, and E genes occur on closely linked loci and are always inherited together as a gene complex.

85%

What is the frequency of "D" antigen in the white population?

70%

What is the frequency of the big "C" antigen in the white population?

30%

What is the frequency of the "E" antigen in the white population?

80%

What is the frequency of the little "c" antigen in the white population?