Biochemistry 1.6 - ABO Blood Typing and Crossmatching (A1 Group 6)
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Transcript of Biochemistry 1.6 - ABO Blood Typing and Crossmatching (A1 Group 6)
ABO Blood Group Biochemistry Basis
GENERAL OBJECTIVES1. Discuss the composition and importance of RBC membrane
2. Discuss the role of genetics and sugar in determining blood type
3. Discuss and compare direct and indirect blood typing: major and minor crossmatching
4. Discuss the biochemical basis of ABO and RH incompatibility
5. Discuss the clinical management of Hemolytic disease of the newborn
Composition of the RBC Membrane Ailen M. Dumas
Objectives• Discuss the composition and importance of the RBC membrane
❑ Illustrate and describe the RBC membrane
• Discuss the role of genetics and sugars in determining the blood type
❑ Explain the role of genetics in determining the blood type, specifically in the oligosaccharide content of the red cell membrane’s glycolipid
Red Blood Cell
Red Cell Membrane
• Consists of the following:
• Proteins - 50%
• Lipids - 40%
• Carbohydrates - 10%
Importance of Red Blood Cell Membrane
✓ T o m a i n t a i n t h e characteristic shape of the red cell
✓ T o s e p a r a t e t h e contents of the cell from the plasma
✓ To regulate intracellular cation concentration
Red Blood Cell General Structure
Role of Genetics and Sugars in Blood Typing
The ABO Blood Group
• A classification of human blood based on the inherited properties of red blood cells
• 4 Phenotypes: A, B, AB, O
The ABO Gene
• Located on chromosome 9
• Codominant in expression
• 3 allelles: A, B, and O
• O gene is considered as amorph
fathermother
A B O
A AA AB AO
B BA BB BO
O OA OB OO
ALLELES BLOOD TYPE
A + A = A
A + O = A
A + B = AB
B + B = B
B + O = B
O + O = O
ABO Group
Antigen on Cell
Antibody in Serum
Genotype
O None Anti-A, B O/O
A A Anti-B A/A or A/O
B B Anti-A B/B or B/O
AB A and B None A/B
The ABO Blood Group Bioanimation
The ABO Blood GroupBioanimation
Rh+ Rh+
Rh+ ++ ++
Rh+ ++ ++
Rh- Rh-
Rh- -- --
Rh- -- --
Rh+ Rh-
Rh+ ++ ++
Rh+ +- --
Rh+ Rh-
Rh+ ++ +-
Rh+ ++ +-
Role of Oligosaccharide Chains on Blood Typing and
CrossmatchingArianne Valerie B. Escritor
Objectives• Discuss the role of genetics and sugars in determining the
blood type
❑ Explain the oligosaccharide sequence in the RBC membrane of the different blood types (A, B, AB, O and Bombay blood type)
❑ Discuss the biochemical basis of blood type determination. What are the different blood types and the immunodominant sugars present in the blood type
▪ Discuss and compare direct and indirect blood typing: major and minor-crossmatching
▪ Discuss the biochemical basis of ABO and Rh incompatibility
ABO Basics• Blood group antigens are actually
sugars attached to red blood cell
• Individuals inherit a gene which codes for specific sugar(s) to be added to the red cell
• The type of sugar added determines the blood group.
Biochemical Structure of Precursor Substance
• A, B and H antigens are built on oligosaccharide chains of 4-types
• The most common forms are Type 1 and Type 2
• Type 1: Carbon one of Gal is attached to the carbon three of GlcNAc
• Type 2: Carbon one of Gal is attached to the carbon four of GlcNAc
Biochemical Structure of H Antigen• Required to produce either A and B antigens
• This also applies to blood type O
H Antigen
• HH and Hh will produce the H antigen
• hh do not produce the H antigen and will have the Bombay phenotype
Bombay Phenotype (Oh)
• Absence of ABH antigens
Biochemical Structure of A Antigen
Biochemical Structure of B Antigen
Biochemical Structure of AB Antigen
• Contains both A and B gene, thus able to produce both A and B antigen
Biochemical Structures
Biochemical Structures
Gene Glycosyl transferases and
Immunodominant Sugars
ABO Blood Group System
• Discovered by Karl Landsteiner and his co-workers
Landsteiner Law: 1. Ag on RBC determines the blood group
2. The corresponding Ab is never found in the individual’s serum
3. The opposite antibody is always present in the individual’s serum
Blood Typing
1. Direct or Forward Typing
– detect Ag on red cells
2. Indirect or Reverse Typing
– detect Ab in serum or plasma
Direct Blood TypingPx
123
Direct Blood TypingPx
123 A B
Direct Blood TypingPx
123 A B
Direct Blood TypingPx
123 A B
Direct Blood Typing
Indirect Blood TypingPx
123
Indirect Blood TypingPx
123
Px 1
23
Indirect Blood TypingPx
123
Px 1
23 A B
Indirect Blood TypingPx
123
Px 1
23 A B
Indirect Blood TypingPx
123
Px 1
23 A B
Indirect Blood Typing
Indirect Blood Typing
Cross-matching
1. Major crossmatch (PS-DR)
- Patient’s serum + Donor’s red cell
2. Minor crossmatch (DS-PR)
- Donor’s serum + Patient’s red cell
Major CrossmatchingD
onor
X
Reci
pien
t Y
Major CrossmatchingD
onor
X
Reci
pien
t Y
Major CrossmatchingD
onor
X
Reci
pien
t Y
Minor CrossmatchingD
onor
X
Reci
pien
t Y
Minor CrossmatchingD
onor
X
Reci
pien
t Y
Minor CrossmatchingD
onor
X
Reci
pien
t Y
Biochemical Basis of ABO and Rh Incompatibility Arianne Valerie B. Escritor
The Rh Blood Group System
• “rhesus” monkey
• Red blood cell surface antigen
• Erythroblastis fetalis - Rh-negative mother is exposed to the Rh-positive blood cells of a fetus
The ABO Blood System
ABO-Rh Incompatibility
• A condition that occurs if two different and incompatible blood types are mixed, causing an immune response in the person, and may sometimes even lead to death.
• Central Dogma of Antibody Production
“One produces an antibody against an antigen foreign to them.”
The ABO Blood System
Clinical Management of Hemolytic Newborn Disease
Karlyn Abigaelle D. Del Rosario, RN
Objectives
• Discuss the clinical management of Hemolytic disease of the newborn
Overview• A.k.a. the hemolytic
disease of the foetus and newborn
• Autoimmune condition that develops in a fetus, when the IgG molecules produced by the mother pass through the placenta
• Among these antibodies, some attacks the RBC’s in the fetal circulation
Pathophysiology of the Disease
Signs and Symptoms• During Pregnancy
• Amniotic fluid may have yellow colouring and contain bilirubin
• Ultrasound of the foetus shows enlarged liver, spleen, or heart, and fluid buildup in the fetus’ abdomen, around the lungs, or in the scalp
Signs and Symptoms
• After Birth
• Pale color due to anemia
• Jaundice
• Enlarged spleen and liver of the newborn
• Anasarca
Diagnosis
• During Pregnancy
• Rh Testing
• Ultrasound
• Amniocentesis
• Coombs Test
Diagnosis
• After Pregnancy
• Testing of umbilical cord blood for blood group, Rh factor, RBC count, and antibodies
• Bilirubin test
Treatment• During Pregnancy
• Intrauterine blood transfusion of RBC into the baby’s circulation
• Early delivery if complications develop
• After Birth
• Blood transfusions
• IV Fluids
• Oxygen therapy
• Intravenous Immunoglobulin (IVIG)
Prevention• Rh (-) mothers are sensitised
by administering Rh immunoglobulin also known as RhoGAM
• RhoGAM is given at the 28th week of pregnancy
• After birth, the mother must receive a second dose of RhoGAM within 72 hours, if her newborn is Rh positive, otherwise, no need for another dose
Thank you! MD-1A | Group 6