Transfusion - Module 1, Part 1

What are the five main concerns when transfusing blood?

Death, bloodborne diseases, sterility of equipment and blood product, oxygen carrying capacity, and clotting.

Why were early historical attempts at blood transfusion doomed?

Due to a lack of basic knowledge of the circulatory system, coagulation, and sterility.

What did Roman spectators do with the blood of dying gladiators?

Rushed to drink it, referring to it as "brave blood".

Who is credited with the first description of how to perform a blood transfusion in 1615?

Andrea Libavius.

Who published the theory of circulation in 1628, removing a major obstacle to transfusion?

William Harvey.

Who is credited with describing the 1st recorded transfusion reaction in 1667?

Jean Denis.

What type of blood did Jean Denis questionably transfuse into a human?

Lamb's blood.

What were the symptoms of the first recorded transfusion reaction?

Pain in kidneys, increased pulse, black urine, nausea, and the patient succumbed.

What was the historical consequence of the first recorded transfusion reaction?

French and British passed legislation prohibiting further blood transfusions.

Who successfully completed the 1st human-to-human blood transfusion in 1818?

James Blundell.

How many of James Blundell's 10 human-to-human transfusions were successful?

4.

What were two early methods used to prevent blood from clotting during transfusion?

De-fibration (removal of fibrin) and addition of chemicals.

Why were early chemical methods to prevent clotting unsuccessful?

They were highly toxic.

What non-toxic chemical was discovered in 1914/15 to prevent coagulation?

Citrate.

What does ACD stand for in blood preservation?

Acid citrate dextrose.

How many days of RBC survival did ACD provide?

21 days.

How many days of RBC survival do current improved preservation solutions provide?

Up to 42 days.

Who discovered the A, B, AB, and O blood groups in 1901?

Karl Landsteiner.

Approximately how many blood group antigens have been added to the list since 1951?

Approximately 300.

What is an antigen?

subtance which intriduced into the body of

During an immune response to a foreign antigen, what do macrophages do to the antigen?

Partially digest it and tag it with RNA to become a super antigen.

After being tagged by a macrophage, what cells is the super antigen presented to?

Immunocompetent T or B cells.

In the humoral immune response, B cell clones differentiate into what?

Plasma cells.

What do plasma cells secrete?

Antibodies.

In the cellular immune response, T cell clones differentiate into what?

TE or TK cells.

What do TE or TK cells produce?

Cytotoxins.

What type of cells are produced in both humoral and cellular immunity that retain information about the antigen?

Memory cells.

What happens when memory cells are exposed to the SAME antigen a second time?

They quickly undergo blast transformation.

What does the humoral response result in the production of?

Antibody "Ab" production (Blood Group Alloantibodies).

How long does it take for the primary response to begin after the first exposure to a foreign antigen?

Approx. 10-14 days (may take several weeks to months).

What class of antibody is mostly produced during the primary response?

IgM.

What class of antibody switches to low levels during the primary response?

IgG.

What is the term for an individual who has produced memory cells after a primary response?

Sensitized.

What is the primary class of antibody produced during a secondary response?

IgG.

How do antibody levels in a secondary response compare to a primary response?

They remain higher for a longer period.

What is an anamnestic response?

When a primary response occurred but was NOT detected, followed by a rapid, high level of IgG Ab production upon re-exposure.

What are the four phases of antibody production in the primary response, in order?

Lag, Log, Plateau, Decline.

During which phase of the primary response are antibody levels low and not detectable?

Lag phase.

During which phase of the primary response are antibodies produced in a logarithmic fashion?

Log phase.

Which antibody rises first in the primary response, IgM or IgG?

IgM.

During which phase of the primary response does antibody production remain stable?

Plateau phase.

During which phase of the primary response is antibody catabolized and detectable levels decrease?

Decline phase.

How does the lag phase of the secondary response compare to the primary response?

It is shorter.

How does the plateau phase of the secondary response compare to the primary response?

It is longer.

How much higher can antibody levels (titre) be in the secondary response compared to the primary response?

As much as 10x higher.

What is active immunization?

When antibodies are stimulated by direct contact with an antigen (occurs in pregnancy and transfusion).

What are immune antibodies produced by active immunization referred to as?

Atypical antibodies.

What two clinical problems can atypical antibodies cause?

Hemolytic Disease of the Newborn (HDN) or Hemolytic Transfusion Reaction (HTR).

In the ABO system, are antibodies naturally occurring or induced by prior red cell exposure?

Naturally occurring (already present without prior exposure).

What happens if the wrong ABO group is transfused?

Immediate Ag/Ab reaction, hemolysis, activation of complement, and death.

What is the main function of an antibody?

To combine with the corresponding antigen.

What may happen if all complement components are activated during a transfusion reaction?

Hemolysis, decreased B.P., shock, organ failure, and death.

What type of incompatibility is usually related to full complement activation and hemolysis?

ABO incompatibility.

What is sensitization in a transfusion reaction?

Antibody attaches to the red cell but complement is NOT activated, leading to removal by the R.E. system.

What happens to red cells sensitized with only some complement components (C1, C4, C2, C3)?

They do not hemolyze but are recognized as abnormal and removed by the R.E. system.

In sensitization and partial complement activation, what is the ultimate result for the transfusion?

Decreased RBC survival of transfused cells (transfusion is not beneficial).

How long do transfused cells remain in circulation?

Up to 3 months.

What percentage of transfused individuals form blood group alloantibodies?

Less than 1%.

What are three reasons why less than 1% of transfused individuals form alloantibodies?

Suppressed immune systems, most RBC Ags are poor immunogens, and insufficient antigen is presented at one time.

What does DHTR stand for?

Delayed Hemolytic Transfusion Reaction.

What is the basic structure of an immunoglobulin molecule called?

A monomer.

How many chains of amino acids compose each immunoglobulin monomer?

4 chains.

What is an immunoglobulin?

A protein capable of acting as an antibody.

What is an antibody?

A specifically reactive immunoglobulin produced in response to a KNOWN antigen.

What are two secondary functions of an antibody, besides binding antigen?

Complement activation and placental transfer.

What are the three specific antigenic determinants on anti-immunoglobulins called?

Isotype, Allotype, and Idiotype.

What is an isotype?

The subclass (class variation) of the immunoglobulin molecule (e.g., IgG, IgM).

Are genes for isotypes present in all healthy members of a species?

Yes.

What is an allotype?

Genetically determined variations in the constant regions of the light chains, unique to the individual's genome.

What is an idiotype?

Genetically determined antigen-binding specificity in the variable regions of the light and heavy chains.

What are the two types of chains that make up an immunoglobulin monomer?

Heavy chains and Light chains.

What holds the two halves of the monomer together?

Inter-chain disulphide bonds.

What holds the lengths of the individual chains together?

Intra-chain disulphide bonds.

What are the folded areas of the immunoglobulin chains called?

Domains or Homology regions.

How many domains and amino acids are in a heavy chain?

3 or 4 domains of about 400 amino acids.

What does the heavy chain determine?

The class of antibody.

What are the five types of heavy chains?

Gamma (γ), mu (μ), alpha (α), delta (δ), and epsilon (ε).

How many domains and amino acids are in a light chain?

2 domains of about 200 amino acids.

What are the two types of light chains?

Kappa (k) or lambda (λ).

How many amino acids build each domain?

About 100 amino acids.

What is the constant region of an immunoglobulin?

The sequence of amino acids that is virtually the same in all immunoglobulins of the same class.

What is the variable region of an immunoglobulin?

The area where the sequence of amino acids changes to match the antigen, conferring specificity.

What is the hinge region?

The area where the molecule is most flexible, allowing it to open so antigen binding sites can adapt to fit the antigen.

What is the suggested shape of an unbound antibody versus a bound antibody?

Unbound is a T-shape; bound is a Y-shape.

Where is the antigen binding site located?

At the terminal juncture of the heavy and light chain.

How many antigen binding sites does each monomer have?

2.

What is an idiotope?

Antigenic determinants on the variable portion of the antibody.

What is an epitope?

The antigenic determinant where the antigen binds to the antibody.

What is a paratope?

The antigen-binding site.

What pages should be reviewed in the Lab Manual before Lab 2?

Pages 4-22.

What are the eight steps performed in Lab 1 for ABO & Rh typing?

Matching sample/requisition, setup and labeling, wash procedure, addition of reagents/samples, use of immune and centrifugation times, grading/interpretation, reporting on worksheet, reporting on requisition.

What does a 4+ agglutination reaction look like?

One solid agglutinate.

What does a 3+ agglutination reaction look like?

Several large agglutinates with a clear background.

What does a 2+ agglutination reaction look like?

Medium-sized agglutinates with a clear background.

What does a 1+ agglutination reaction look like?

Small agglutinates with a turbid background.

What does a W+ agglutination reaction look like?

Tiny agglutinates with a turbid background.

What does a 0 agglutination reaction look like?

No agglutination or hemolysis.

Is partial or complete hemolysis considered a positive reaction?

Yes.

What are the five reasons red cells are washed?

To remove trace amounts of plasma proteins, remove fragile cells, remove soluble group substances, remove anticoagulant (EDTA), and remove solutions from commercially prepared red cells.

How long are tubes centrifuged during the cell washing procedure?

1 minute on high speed.