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All humans possess isoantigens on their red blood cells that are unique to the species.
All humans possess isoantigens on their red blood cells that are unique to the species.
True
The only blood type that lacks both A and B antigens is known as group AB.
The only blood type that lacks both A and B antigens is known as group AB.
False
The antibodies present in a person's serum are determined by the antigens on their red blood cells.
The antibodies present in a person's serum are determined by the antigens on their red blood cells.
True
Karl Landsteiner discovered that cross-testing blood samples can identify compatible blood types.
Karl Landsteiner discovered that cross-testing blood samples can identify compatible blood types.
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Bernstein proposed that there are four allelic genes determining the ABO blood groups.
Bernstein proposed that there are four allelic genes determining the ABO blood groups.
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Antigen A is found on individuals who belong to blood group B.
Antigen A is found on individuals who belong to blood group B.
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Individuals with group A blood will produce antibodies against antigen B.
Individuals with group A blood will produce antibodies against antigen B.
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The presence of different red cell antigens is irrelevant to blood transfusion compatibility.
The presence of different red cell antigens is irrelevant to blood transfusion compatibility.
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The O gene is considered amorphic because it produces detectable antigens.
The O gene is considered amorphic because it produces detectable antigens.
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The inheritance of the A and B genes is influenced by the H gene.
The inheritance of the A and B genes is influenced by the H gene.
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The A gene produces N-acetyl galactosaminyl transferase.
The A gene produces N-acetyl galactosaminyl transferase.
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If a person does not inherit at least one H gene, they will still produce the H substance.
If a person does not inherit at least one H gene, they will still produce the H substance.
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The B gene produces an enzyme that converts the H substance directly into O antigens.
The B gene produces an enzyme that converts the H substance directly into O antigens.
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The O allele alters the structure of the H antigen.
The O allele alters the structure of the H antigen.
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The A gene codes for the addition of N-acetylgalactosamine to the H antigen.
The A gene codes for the addition of N-acetylgalactosamine to the H antigen.
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Individuals with blood type O possess the least amount of H antigen.
Individuals with blood type O possess the least amount of H antigen.
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Group A individuals have more H antigen sites than Group B individuals.
Group A individuals have more H antigen sites than Group B individuals.
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Secretors and non-secretors refer to the presence of water-soluble A, B, and H antigen substances in body fluids.
Secretors and non-secretors refer to the presence of water-soluble A, B, and H antigen substances in body fluids.
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About 80% of Caucasians possess the Se gene, which is important for the secretion of blood group antigens.
About 80% of Caucasians possess the Se gene, which is important for the secretion of blood group antigens.
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The formation of the B antigen involves the addition of D-galactose to the H antigen.
The formation of the B antigen involves the addition of D-galactose to the H antigen.
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There are equal proportions of Group A1 and Group A2 individuals in the population.
There are equal proportions of Group A1 and Group A2 individuals in the population.
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The serologic distinction between A1 and A2 is based on the reactions of erythrocytes to various antisera.
The serologic distinction between A1 and A2 is based on the reactions of erythrocytes to various antisera.
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Type B blood has more common subgroups than type A blood.
Type B blood has more common subgroups than type A blood.
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Acquired A antigen can occur in individuals with type O blood during severe infections.
Acquired A antigen can occur in individuals with type O blood during severe infections.
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The group A2 contains anti-A1 in up to 2% of its serum.
The group A2 contains anti-A1 in up to 2% of its serum.
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A2B blood typically contains no antibodies in the serum.
A2B blood typically contains no antibodies in the serum.
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A superactive B transferase can lead to a deficit of A antigen sites on erythrocytes in some AB individuals.
A superactive B transferase can lead to a deficit of A antigen sites on erythrocytes in some AB individuals.
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Mixed field agglutination is a reaction visible microscopically when anti-A reagents interact with type AB blood.
Mixed field agglutination is a reaction visible microscopically when anti-A reagents interact with type AB blood.
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High levels of soluble ABH substances can suppress the expression of A, B, and H antigens on erythrocytes.
High levels of soluble ABH substances can suppress the expression of A, B, and H antigens on erythrocytes.
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Acquired B-like antigen was first recognized in 1959 with conditions such as intestinal obstruction.
Acquired B-like antigen was first recognized in 1959 with conditions such as intestinal obstruction.
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The deacetylation of the A1 antigen by bacterial enzymes does not cause any change in the antigen.
The deacetylation of the A1 antigen by bacterial enzymes does not cause any change in the antigen.
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High levels of soluble ABH substances can occur in conditions like ovarian cysts and intestinal obstruction.
High levels of soluble ABH substances can occur in conditions like ovarian cysts and intestinal obstruction.
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Weakening of the A antigen is typically not noted in patients with leukemia and lymphoma.
Weakening of the A antigen is typically not noted in patients with leukemia and lymphoma.
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Immune antibodies of the P, Lewis, and MN systems are commonly detected and are of significant clinical importance.
Immune antibodies of the P, Lewis, and MN systems are commonly detected and are of significant clinical importance.
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The M antigen is carried on glycophorin A and is detected on chromosome 4q28-q31.
The M antigen is carried on glycophorin A and is detected on chromosome 4q28-q31.
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Among white people, the incidence of the M+N- phenotype is 50%.
Among white people, the incidence of the M+N- phenotype is 50%.
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MN antibodies react at temperatures only up to 37°C.
MN antibodies react at temperatures only up to 37°C.
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The K antigen is found in 9% of the English population.
The K antigen is found in 9% of the English population.
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The Jsa antigen is present at a frequency of 99.9% in the Caucasian population.
The Jsa antigen is present at a frequency of 99.9% in the Caucasian population.
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The genes associated with the Kell antigen system include K, k, Kpa, Kpb, Jsa, and Jsb.
The genes associated with the Kell antigen system include K, k, Kpa, Kpb, Jsa, and Jsb.
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Individuals with Kell antigens are known to have no association with transfusion reactions.
Individuals with Kell antigens are known to have no association with transfusion reactions.
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MN antigen is generally considered clinically significant at a temperature of 37°C.
MN antigen is generally considered clinically significant at a temperature of 37°C.
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Study Notes
The ABO Blood Group System
- The ABO blood group system is a classification of human blood types based on the presence or absence of specific antigens (A and B) on the surface of red blood cells (RBCs) and corresponding antibodies in the blood plasma.
- Different blood types have specific antigens present on their RBCs. These antigens are unique for each species.
- Isoantigens are inherited antigens found on RBCs that are unique to a particular species.
- Alloantigens are antigens found in some members of a species but not all. They can induce alloantibodies in individuals who lack them
- Blood group serology involves detecting these antigens and antibodies, essential for blood transfusions.
- Karl Landsteiner's discovery in the early 20th century revolutionized blood transfusions, demonstrating that incompatible blood mixing could lead to severe reactions. Cross-testing blood samples showed that some mixed successfully while others reacted strongly, highlighting the importance of compatibility testing.
- Agglutination (clumping) of red blood cells occurs when an antigen on the RBC surface interacts with an opposing antibody in the serum.
- The ABO system comprises four blood types: A, B, AB, and O. Individuals with type A blood have only A antigens on their RBCs, type B have only B antigens, type AB have both A and B antigens, and type O have neither A nor B antigens.
Blood Group Antigens
- The A and B antigens develop on the surface of red blood cells based on the H antigen, existing as a precursor substance.
- The H antigen is formed when L-fucose is added to the precursor substance.
- The A gene produces N-acetylgalactosaminyltransferase to add N-acetylgalactosamine sugar to the H antigen.
- The B gene produces D-galactosyltransferase, adding D-galactose sugar to the H antigen
- The O gene doesn't produce a transferase enzyme.
Gene Sequence
- In 1924, Bernstein postulated three allelic genes (A, B, and O) controlling the ABO blood group system, inheriting one gene from each parent.
- The O gene is considered amorphic because no detectable antigen is produced in response to its inheritance.
Blood Group Antigens Expression
- The expression of A and B genes on RBCs and body fluids is based on inheriting Hh, Sese, and A and B genes, with the latter located on chromosome 9 and the former on chromosome 19.
Secretion of Antigens
- The presence of the Se gene influences the secretion of A, B, and H antigens in body fluids, essential for testing in various situations.
Type A Subgroups
- The A antigen group can be divided into subgroups like A1 and A2, with A1 being more prevalent (80%). A2 shows weaker reactions.
Type B Subgroups
- Type B blood subgroups are less common than A subgroups.
Other Blood Group Systems
- Other blood groups, such as MNSS, Kell, Lewis, Duffy, Kidd, and others, are present within the human population.
- These blood systems are less clinically important than ABO or Rh.
- Antibodies in these systems sometimes appear under different conditions.
- Several blood-type systems are known but the clinical importance of most groups, while present, is only in rare cases
Rh System (Rhesus Factor)
- Discovered by Landsteiner, Wiener, and Levine/Stetson.
- Presence/absence of the RhD antigen is crucial.
- Absence (Rh−) of the RhD antigen in a mother can lead to hemolytic disease when a fetus (Rh+) inherits a different condition.
- Rh antibodies produced in the mother during pregnancy can destroy the fetal RBCs leading to complications
- Various combinations of related blood group antigens exists (CDEcde) on the same chromosome.
Antibody Types
- Naturally occurring antibodies may be present if the antigen is absent
- Reactive at 37°C are called warm antibodies like Anti-D
- Reactive at 4°C are called cold antibodies like Anti-A and Anti-B
- Immune antibodies are generated in response to antigen exposure.
Useful applications of Blood Groups
- Used to prevent transfusion reactions
- Used in forensic science and paternity testing
- To identify disease states, such as those impacting RBCs
- Important for organ transplantations
Detection of Blood Groups
- Antibody screening and cross-matching tests are frequently employed in transfusion medicine to assess blood group compatibility.
- Agglutination of red blood cells with specific antibodies is a standard method of identification.
- Coombs tests are crucial for diagnosing conditions like autoimmune hemolytic anemia.
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Description
Explore the ABO blood group system, a fundamental classification of human blood types based on the presence of antigens on red blood cells. Understand the roles of isoantigens and alloantigens in blood compatibility and the historical significance of Karl Landsteiner's discoveries in blood transfusion practices.
