Blood Bank Week 1

Who administered the first man-to-man transfusion?

James Blundell

Who discovered the ABO Blood Groups?

Karl Landsteiner and his students

Define: chromosome

Structures within the nucleus that contain DNA

Define: gene

Basic unit of inheritance of a chromosome

Define: linkage

When two genes are inherited together by being very close to a chromosome

Define: private genes

Exceedingly rare and are often found in a particular race or family

Define: loci

Sites of a gene on the chromosome

Define: allele

Alternate forms of a gene on a chromosome

Define: heterozygous

Two alleles of a given trait are different

Define: homozygous

Two alleles for a given trait are the same

Define: codominant gene

Equal expression of two different inherited alleles

Define: genotype

Actual genetic makeup of an organism
Determined by family studies

What is the most common pattern of inheritance for blood group genes?

Codominant

What is a non-red cell stimulated (naturally occurring) antibody?

Antibodies that occur without known allergenic stimulus (ABO)

What is an immune antibody?

Antibodies that occur as a result of red cell stimulation

Which immunoglobulin molecules are most frequently encountered in blood banking?

IgM
IgG

Compare the molecular structure of IgG and IgM and explain how their structureaffects their reactivity in blood bank testing.

IgG: incomplete antibody that has to be enhanced to combine with an antigen due to their size. Reacts best at 37 degrees C
IgM: complete antibody that can produce agglutination at room temp

Which immunoglobulin is most efficient at activating complement?

IgM

Which immunoglobulin can cross the placenta?

IgG

What is sensitization?

The binding of an antibody or complement components to a red cell

List several factors that affect sensitization phase of agglutination

Antibody-Antigen ratio
Time
pH
Ionic strength
Temperature
Incubation time

What are 2 visible signs of antibody-antigen reaction in blood bank testing?

Agglutination
Hemolysis

What is an antibody?

Glycoproteins that facilitate the clearing of antigens

What is an alloantibody?

Antibodies with specificities other than self
Stimulated by pregnancy, transfusion, or transplant

What is an autoantibody?

Antibodies to self-antigens

What type of routine testing does the blood bank perform when determining the bloodgroup of a patient?

Phenotype

What type of B cells are formed after antigen stimulation?

Memory B cells
Plasma cells

Describe the difference between primary and anamnestic response

Primary: first exposure to an antigen. Takes longer to produce antigens. IgM is the main antibody produced
Anamnestic: subsequent exposure to an antigen. Shorter response time. IgG is the main antibody produced

Explain the correct way to examine a tube for signs of an antigen-antibody reaction.

Agglutination checked with a mirror by flicking the wrist

How would three large agglutinates against a clear background be graded?

3+

In blood bank records, what must be recorded in addition to the degree of reactivity in all phases of testing?

Hemolysis; serum must be present

List 4 types of blood bank reagents

Antibodies/Antiseras
Reagent Red Blood Cells
Enhancement medias
AHGs (anti-human globulins)

Who regulates the production of blood bank reagents?

FDA

Describe the following reagent anti-seras: Polyclonal

Made of several different clones of B cells that secrete antibodies of different specificities

Describe the following reagent anti-seras: Monoclonal

Made from single clones of B cells that secrete antibodies of the same specificities

What is the purpose of the IAT?

Antibody detection and identification
Rh typing of D antigen
Compatibility testing
IgG reactions

List some causes of false positive test results in the IAT.

Bacterial contamination
Overcentrifugation
Use of a clotted specimen
Poor technique

List some causes of false negative test results in the IAT

Failure to add AHG
Inadequate washing of red cells
AHG inactivates due to improper storage or contamination
Low affinity between red cells and the IgG antibody

What are antibody enhancers?

Reagents that increase the rate of Antigen-Antibody uptake and reduce the time needed to obtain a reaction

Name 4 antibody enhancers

Low-Ionic-Strength Saline
Polyethylene Glycol (PEG)
Proteolytic Enzymes (Papain & Ficin)
Bovine Serum Albumin (BSA)

Describe how the antibody reaction is enhanced with: Low-Ionic-Strength Saline

reduces ionic strength of suspending media (lowers zeta potential), moves Ag and Ab together more rapidly

Describe how the antibody reaction is enhanced with: Polyethylene Glycol (PEG)

increased Ab uptake, detects/IDs weak IgGs

Describe how the antibody reaction is enhanced with: Proteolytic Enzymes (Papain & Ficin)

Removes negative charges from the red cell membrane, which reduces the zeta potential
Denatures same red cell antigens

Describe how the antibody reaction is enhanced with: Bovine Serum Albumin (BSA)

reduces net charge of RBCs allowing them to come closer

agglutination grading

0 = negative
1+ = small agglutinates, free red cells in background
2+ = medium agglutinates, clear background
3+ = several large agglutinates, clear background
4+ = one solid agglutinate
H = hemolysis
MF = mixed field; large agglutinate in background of free cells

Describe the ABO forward grouping procedure.

Unknown patient red cells are tested in a 2-4% solution using anti-A and anti-B antiseras

List the agglutinogens (Ag) for the ABO groups.

Group O: H antigen
Group A: A & H antigens
Group B: B & H antigens
Group AB: A, B, & H antigens

List the agglutinins(Ab) for the ABO groups.

Group O: primarily IgG
Group A & B: primarily IgM with small amounts of IgG

What percentage of the population in the U. S. are secretors?

80%

What does inheritance of SeSe or Sese genes indicate about a person's ABH antigens?

SeSe or Sese = secretors
sese = non-secretors

Given the following genotypes of the parents, indicate the possible genotypes of their children. Mother AO, Father AB.

AA
AB
Ao
Bo

Describe chimerism and the ABO system

Individuals that contain dual populations of red cells
One population will agglutinate while the other will not
Look for mixed field

Which terminal sugar must be added to L-fucose to produce "A" antigen on the red cells?

N-acetylgalactosamine

Which terminal sugar must be added to L-fucose to produce "B" antigen on the red cells?

D-galactose

Indicate how these cells differ: T activated cells

Removal of Sialic acid
Exposing cryptantigens

Indicate how these cells differ: Tn activated cells

Decreased Sialic acid
Associated with Hematologic disorders

Indicate how these cells differ: CAD activated cells

High level of Sd^a antigen
Plant lectins are used to identify these

If anti-H lectin is added to red cells of the Bombay phenotype, what reaction would occur?

No reaction

Individuals with proteus mirabilis infection may exhibit an acquired antigen. Which antigen is this?

A

From which plant are these lectins derived: H lectin

Ulex europaeus

From which plant are these lectins derived: A1 lectin

Dolichos biflorus

Which antibodies are present in the serum of a person with the Bombay phenotype?

Anti-A
Anti-B
Anti-H

H antigens are absent from the red cells of which phenotype?

Bombay

Individuals with E. coli or Proteus vulgaris infections may exhibit which acquired ABO antigen?

B

Which blood group has the most H antigen left on the red cells?

O

Which blood group has the least H antigen left on the red cells?

A1B

Write the results of forward and reverse grouping that would correspond to an acquired 'B' antigen

Forward: Anti-A, Anti-B
Reverse: B

What happens to the 'A' antigen in leukemia or lymphoma?

They weaken the A antigen; affects forward typing

Describe the characteristics of ABO antibodies.

IgM
React best at room temp
Requires no enhancement or incubation

Which subgroup(s) of A can produce immune anti-A1?

Group A3...so on
GroupA2 possible, but not likely

What forward and reverse grouping pattern may be observed on an elderly patient?

Forward: normal
Reverse: weak or missing reactions

What procedure should be used if a cold agglutinin clumps all the cells used in the forward and reverse grouping tests?

Identify antibody and retype with prewarming techniques

Describe the two theories of why naturally occurring ABO antibodies develop.

Genetic
Environmental

What is mixed field agglutination? List two causes of this observation.

The presence of two populations of red cells
Chimerism
Transfusion of type O blood into a type A, B, or AB individual

Describe rouleaux and indicate how it can be dispersed.

Psuedoagglutination "stacks of coins"
Saline replacement procedure

Why is the reverse grouping test not done on newborns?

They have yet to develop ABO antibodies

Indicate how to resolve the ABO discrepancies listed: Tn activation

Treat cells with enzymes to destroy Tn antigen, then type cells

Indicate how to resolve the ABO discrepancies listed: CAD activation

Plant lectins

Indicate how to resolve the ABO discrepancies listed: Cold Autoantibodies

Identify antibody and use use prewarm techniques to retype

Indicate how to resolve the ABO discrepancies listed: Cold Alloantibodies

ID Ab and retype with Ag negatice cells, use prewarm technique

Indicate how to resolve the ABO discrepancies listed: T activation

Test cells with cord serum which has no anti-T

Indicate how to resolve the ABO discrepancies listed: Hypogammaglobulinenemia

Increase incubation time for reverse typing tubes for 15 minutes at RT

Indicate how to resolve the ABO discrepancies listed: Immunosuppression

Determine diagnosis
Increase incubation time for reverse typing tubes for 15 minutes at RT

Indicate how to resolve the ABO discrepancies listed: Bone Marrow transplants

Check patient history for evidence of dual population of red cells

Indicate how to resolve the ABO discrepancies listed: Weak or missing antigens

Incubate at RT longer
Use of lectins for typing
History of disease states

Indicate how to resolve the ABO discrepancies listed: Weak or missing antibodies

Incubate at RT longer
Always including an autocontrol

1. What does the term Rh positive indicate?

Rh positive = DD or Dd

1. What does the term Rh negative?

Rh negative = dd or no antigen

2. Are weak D positive individuals considered Rh positive?

yes

3. List 5 compound antigens associated with the Rh system.

f (ce)
Rh7 (Ce)
Rh27 (cis cE)
Rh22 (cis CE)

4. What is indicated by the term Rh null?

Absence of all Ag; causes "floppy" RBC; when transfusion is necessary only Rh null blood can be used

5. What percentage of the population is Rh positive?

85%

5. What percentage of the population is Rh negative?

15%

6. What is the significance of the LW antigen?

It is the animal equivalent to the Rh (D) antigen

7. Which individuals should receive Rh negative blood?

People with Rh(D) negative; priority is given to women of child-bearing age

8. What are Rh gene deletions? How are they designated?

-D- or D--
no reactions with anti-E, anti-e, anti-C, or anti-c
Stronger D antigen activity
Transfuse only D- deleted cells

9. When is the G antigen found?

Weakly expressed and is associated with the presence of the D or C antigen (NOT a compound Ag; both do not have to be inherited for G Ag to be present)

10. Rank the 5 basic Rh antigens in order of decreasing antigenicity?

D > c > E > C > e

11. Describe three ways the weak D status can be inherited.

Genetic- inheritance of D genes which result in lowered densities of D antigens on RBC membranes
C trans- position effect; the D gene is in trans to the C gene, Dce/dCe
D mosaic- 1 or more parts of the D antigen is missing; may result in production of Anti-D

12. What type of blood should be given to weak D positive individuals? (Especially women of childbearing age)

Rh negative products