Intro to Immunohematology Flashcards
Blood banking
collecting, storing, and processing blood. Plus distribution of red blood cells and blood components
Immunohematology
-academic knowledge and procedures involving the study of immunological response to blood components
Transfusion medicine
-The medical practice and techniques associated with procurement, processing, and distributing blood or blood components to patients
Why do we do transfusion therapy?
- Inadequate oxygen-carrying compacity because of anemia or blood loss
- Insufficient coagulation proteins or platelets to provide adequate homeostasis
* In rare cases they can do transfusions of granulocytes (WBCs)
Antibody
-also called immunoglobulin
-is a protein substance found in plasma or other body fluids that is formed as a result of antigenic stimulation and is specific for antigens against which it is formed
Antigen
-A foreign substance that can cause an immune response and formation of corresponding antibodies.
-they are generally but not always found on the red cell membrane
Gene
a unit of inheritance on a chromosome and made up of DNA
allele
different forms of a gene
Homozygous
having two identical alleles
heterozygous
having two different alleles
locus
-the specific physical location of a gene or other DNA sequence on a chromosome
codominance
-the two inherited genes are both expressed and neither is dominant over the other
genotype
-the actual total genetic makeup of an individual
phenotype
-the outward expression of genes (observable traits)
Immunology is responsible for
the study of the molecules, cells, organs, and systems responsible for
1. Recognition and disposal of nonself substances
2. Response and interactions of body components and related interactions
3. how the immune system can be manipulated to protect against or treat disease
in vivo
-Living inside the body
in vitro
-Outside the living body, such as a lab setting on a slide or in a test tube
What are the five different immunoglobulin classes?
- IgG
- IgM
- IgD
- IgA
- IgE
Fab region
-antigen binding region
Fc region
-complement binding region
What are the characteristics of an IgG antibody?
- React best at 37 degrees
- capable of placental transfer
- able to bind complement
What are the characteristics of an IgM antibody?
- Naturally occurring (ex: ABO antibodies)
- Pentameric configuration
- Unable to pass the placenta
- Able to bind complement more efficiently than IgG antibodies
- React best at room temp (22-24 degrees)
Naturally occurring antibodies
-are antibodies formed in individuals who have never been previously exposed to RBC antigens by the following methods
1. transfusion
2. injection
3. pregnancy
How are naturally occurring antibodies formed?
- Environmentally acquired
- Bacterial membranes
Most of these antibodies are cold agglutins (ex: (IgM cold agglutinin, isoagglutinin, and antibodies against antigens of the Lewis, MN, and P blood group systems
Isoagglutinins
-are the ABO antibodies; anti-A, anti-B, and anti-AB
Immune antibodies
-antibodies found in individuals who have been previously exposed to RBC antigens through either
1. transfusion
2. pregnancy
-Most immune antibodies are IgG antibodies
ex: antibodies against antigens in the Rh, Kell, Duffy, Kidd, and Ss blood group systems
What is complement?
-Group of proteins that have functions including antigen clearance and cell lysis
-circle in an inactive state (proenzymes)
-are activated in a cascade of events
-3 main pathways
What is the function of the complement?
- cell lysis
- antigen clearance
What are the three main complement pathways?
- classical
- alternative
- lectin
Why is the complement system important in transfusion medicine?
-antibody-antigen binding can trigger complement and ultimately form the membrane attack complex, lysing red blood cells and resulting in hemolytic adverse transfusion reactions
agglutination
precipitate antigens such as RBCs react with the specific antibodies and form visible clumping
precipitation
-the formation of a visible complex as a result of antigen-antibody reaction between soluble antigen and its specific antibody
What are the factors that can influence the amount of antigen-antibody binding?
- pH
- Temperature
- incubation time
- antigen-antibody ratio
hemagglutination
-a special name for the agglutination of red cells due to antigen-antibody reaction
Prozone
-an excess of antibodies relative to the number of antigen sites
-can give a false negative reading
hemolysis
-rupture/lysis of red cell membrane and release of hemoglobin from the red cell due to the activation of complement and the formation of the MAC caused by antigen-antibody binding
-clear, red solution with no cloudiness
Sensitization
-first phase of agglutination where the antibody molecules physically attach to antigens on the red cell membrane
Lattice formation
-the second phase of agglutination where the establishment of cross-links between sensitized particles and antibodies, which result in aggregation
-much slower than the sensitization phase
Zone of equivalence
-optimal antigen-antibody binding ratio that is necessary for agglutination reaction to occur
postzone
-concentration of antigen exceeds the number of antibodies present
-can give a false negative reaction
incubation time
-allowing adequate time for the combo of antigen-antibody to attain equilibrium, enhances agglutinins reaction
temperature
-Different antibodies need different optimum temperatures to reach equilibrium in an antigen-antibody reaction
pH
-a pH of 7.0 is routinely used in the lab as it is similar to the pH of normal plasma/serum
Immunoglobulin Type
-IgM is more efficient in agglutination reactions, and easily bridges the gap between 2 RBCs due to size and structure. More antibody sites
centrifugation
-enhances agglutination and decreases reaction time by increasing gravitational forces on the reactants and bringing them closer together
-In sensitized RBCs to overcome natural repulsive effects
Enhancement media
-IgM: agglutinins reaction accomplished in saline solution
-IgG: LISS (low ionic strength solution)
LISS (Low ionic strength solution)
-reduces the zeta potential of RBC molecules
-Usage can increase antibody uptake during sensitization and decrease incubation time
Anti A: Characteristics
- Predominately class IgM, small amount IgG
-The optimal temperature is room temp
-efficiently activate complement at 37 degrees (True)
Anti B: Characteristics
-Predominately class IgM, small amount IgG
- The optimal temperature is room temp
-efficiently activate complement at 37 degrees (True)
Anti AB: Characteristics
- Class IgG
-The optimal temperature is room temp - effectively activates the complement at 37 degrees (true)
