ABO Blood Group System Overview

A system that classifies human blood types based on the presence or absence of specific antigens (A and B) on red blood cells and corresponding antibodies (anti-A and anti-B) in the serum.

Antigens unique to a particular species, including humans.

Antigens common to some but not all members of a species, capable of triggering antibody production in those lacking them.

Red blood cells possessing only the A antigen.

Red blood cells possessing only the B antigen.

Red blood cells possessing both A and B antigens.

Red blood cells lacking both A and B antigens.

The clumping of red blood cells when incompatible blood types are mixed.

The O gene is an amorphic gene, meaning it doesn't produce a detectable antigen, or enzyme, and no H substance.

The A and B genes produce enzymes (transferases) that alter the H substance to form the A or B antigens. The presence of these genes determines whether A, B, or neither antigen is expressed in body fluids and red blood cells

The H gene produces the enzyme L-fucosyl transferase, which adds L-fucose to the precursor substance, creating the H substance.

Blood types A, B, and O are produced based on an inheritance of genes that determine whether the precursor substance is converted to A, B, or neither antigen using enzymes.

Blood type inheritance follows a dominant and co-dominant pattern. A and B are dominant to O, and A and B are co-dominant.

The foundation for A and B antigens; a carbohydrate structure on red blood cells.

Specific carbohydrate structures on red blood cells, determined by the A and B genes, which code for enzymes that add sugar to the H antigen.

O blood types have more H antigen than others, as the O gene is essentially a no-op gene when constructing the H antigen. It doesn't alter the structure of the H antigen.

A gene influencing the presence of water-soluble A, B, and H antigens in body fluids.

Two subtypes of the A blood type determined by genetic differences. A1 is more prevalent.

Sugar added by the A gene's enzyme to create the A antigen.

Sugar added by the B gene's enzyme to create the B antigen.

Blood types (O, A1, A2, B, A1B, A2B) are determined by the specific sugars attached to the H antigen.

A blood group system characterized by the Kell antigen, which is clinically significant due to its potential for causing transfusion reactions and hemolytic disease of the newborn (HDN).

A protein found on the surface of red blood cells, responsible for the Kell blood group system.

The frequency of Kell blood types varies in different populations. For example, the K antigen is more common in English populations than in Black populations.

The Kell antigen, a zinc metalloprotein, has endopeptidase activity, playing a role in cell processes related to its function.

The Kell antigen gene is located on chromosome 7q33, a specific region of chromosome 7.

The difference between A1 and A2 blood types is determined by how their red blood cells react to specific antisera, particularly anti-A serum from a Group B individual.

Some A2 or A2B individuals have antibodies in their serum that specifically target the A1 antigen.

The A2 blood type is less reactive and doesn't usually require special attention in transfusions, except when working with A2 or A2B individuals who possess anti-A1 antibodies.

There are several subgroups or variants of the B blood type, though they're less common than A subgroups.

The classification of B subgroups has involved factors like race and Sanger's research.

In some cases, the presence of specific genes can modify the expression of ABH antigens on red blood cells, affecting the blood type.

Under specific conditions, such as severe infections with Proteus mirabilis, individuals of blood types O or B can acquire an A antigen.

The acquired A antigen can lead to mixed field agglutination when reacting with anti-A serum, meaning some cells clump together while others don't.

A temporary expression of the B antigen in individuals with blood type A, usually caused by bacterial infection.

Individuals with the A1 blood type are more susceptible to acquiring the B-like antigen due to the specific structure of their A antigen.

The removal of an acetyl group from a molecule, specifically the A1 antigen in this case, leading to a change in its structure and potential expression of B antigen.

Free-floating molecules in the blood that contain the A, B, or H antigens. High levels can interfere with blood typing tests.

The inactivation of antibodies (anti-A or Anti-B) by soluble ABH substances, preventing them from reacting with blood cells in a typing test.

A decrease in the levels of A, B, or H antigens on red blood cells, potentially caused by medical conditions like leukemia or lymphoma.

A blood group system less clinically significant than ABO, determined by proteins called glycophorins A and B.

Proteins expressed on red blood cells belonging to the MNSs blood group system.