(P) Other Blood Groups [AI GENERATED] Flashcards
What is a chromosome?
The structure within the nucleus that contains a linear thread of DNA which transmits genetic information.
Define gene.
A unit of inheritance within a chromosome.
What are alleles?
One of two or more different genes that may occupy a specific locus on a chromosome.
What does dominant mean in genetics?
A trait or character that will be expressed in the offspring.
What is codominance?
A pair of genes that are both dominant and both expressed.
Define amorphic gene.
A silent gene; a gene that does not produce a detectable antigen (e.g., Type O gene).
What is a null phenotype?
When paired chromosomes carry the same silent allele.
What are autosomes?
Any chromosome other than the sex chromosomes (X & Y); 22 autosomes and 1 sex chromosome.
Define heterozygous.
Possessing different alleles at a given gene locus.
Define homozygous.
Possessing a pair of identical alleles.
What is the role of the International Society of Blood Transfusion (ISBT) Working Party?
Maintains an official record of all currently recognised blood group systems.
How many blood group systems are recognized as of June 2021?
43 recognized blood group systems containing 345 red cell antigens.
What is a blood group system (BGS)?
One or more antigens produced by alleles at a single gene locus or loci.
What is the significance of genetic variation in blood group systems?
The underlying genetic variation must be identified, sequenced, and confirmed to affect phenotype.
What does serologic definition of an antigen entail?
Testing with the corresponding antigen through serologic testing, like phenotyping or blood typing.
What are high prevalence antigens?
Antigens that have more than 99% prevalence or frequency in the general population.
What are low prevalence antigens?
Antigens that occur less than one percent (1%) of the population.
Fill in the blank: Genes are written in _______ when handwritten.
[italics or underlined].
What does IgM indicate in terms of antibodies?
Commonly does not bind complement and is often found in anti-M and anti-N antibodies.
What is the phenotype of an individual?
Refers to the antigens present on an individual’s RBCs and indicates the results of serologic tests on those RBCs.
What is the frequency of the M+N- phenotype in Whites?
28%.
What is the frequency of the S-s+ phenotype in Blacks?
69%.
True or False: The P blood group system’s biological role is well understood.
False; biological role is still unknown.
What is the significance of GPA and GPB in the P blood group system?
They serve as receptors for Plasmodium falciparum.
What does the term ‘alloantibodies’ refer to?
Antibodies that develop when exposed to a non-self or foreign antigen.
What characterizes the MNS blood group system?
It consists of more than 46 antigens, with M/N and S/s being commonly encountered in clinical settings.
What are the common antigens in the MNS blood group system?
M, N, S, and s.
What does dosage in antibodies refer to?
Stronger reaction if expressed as homozygous.
What is the phenotype for U (Universal antigen)?
High-incidence, resistant to enzyme treatment.
Define anti-M.
Commonly IgM, does not bind complement, and does not react with enzyme-treated RBCs.
True or False: The anti-N antibody is more common in adults than in children.
False; it is more common in children.
What is the frequency of the M-N- phenotype in Whites?
22%.
What is the significance of the ‘U’ antigen?
It is a universal antigen found in GPB.
What are the plant extracts used as antisera for M&N blood group antigens?
Anti-M: Iberis Amara, Anti-N: Vicia graminea
Both are plant-based lectins used in blood typing.
What is the common precursor of the P blood group antigens?
Lactosylceramide (Gb2)
Also known as ceramide dihexose.
What are the P blood group antigens resistant to?
Ficin, papain, DTT, chloroquine, glycine-acid EDTA
These treatments do not affect the P blood group antigens.
What is the gene that codes for the P1 PK antigen?
P1 PK Gene at Chromosome 22
The Globoside Gene is located at Chromosome 3.
Fill in the blank: The P blood group antigens are _______ in nature.
Glycosphingolipids
What is the significance of the P1 antigen expression on RBCs?
Uniquely expressed on RBCs and poorly expressed at birth
Takes about 7 years to become fully expressed.
What is the clinical significance of anti-P1 antibodies?
Rarely significant; may cause in vivo RBC destruction if reactive at 37°C
Associated with immediate and delayed hemolytic transfusion reactions.
What are the disease associations of the P1 antigen?
Hydatid cyst disease, fascioliasis, and infections from bird droppings
Titers are often elevated in these conditions.
What is the Donath-Landsteiner test used for?
To detect biphasic hemolysins in patients with paroxysmal cold hemoglobinuria
Involves incubating patient serum with P-positive RBCs at different temperatures.
What are the common antigens found in the P blood group system?
P, P1, Pk
Pk and P antigens are high-frequency antigens on donor RBCs.
Fill in the blank: The enzyme that codes for the P antigen is _______.
A4GALT
What type of antibodies are associated with the P blood group system?
IgM and IgG
Anti-P antibodies can cause hemolysis and are significant in transfusion reactions.
What is the association of the Pk antigen with infectious diseases?
Receptor for microbial pathogens including E. coli and Shiga toxins
Pk individuals lack P antigen, providing resistance to certain infections.
What is the frequency of the PX2 antigen in the population?
> 99.9%
Expressed on cord cells and enhanced by enzyme treatment.
What are null or weak phenotypes in the P blood group system?
Three autosomal recessive null phenotypes and weak variants
Associated with the Pk variant and LKE-negative phenotype.
What does the Lutheran blood group system belong to?
Protein superfamily
Located on Chromosome 19 and contains 20 antigens.
What is the expression pattern of Lutheran glycoprotein?
Appears at the Orthochromatic Erythroblast Stage
Concurrent with binding of red cells to laminin.
What is the significance of anti-PP1Pk antibodies?
Associated with hemolytic transfusion reactions and habitual early abortions
Can cause hemolytic disease of the fetus and newborn (HDFN).
What is the copy range for Luᵇ?
1640 - 4070 copies
What are the two forms of Lutheran glycoprotein?
- Longer Lu Glycoprotein
- Shorter Basal Cell Adhesion Molecule (B-CAM)
What is the frequency of Homozygous B (Lu (a⁻b⁺)) in Whites and Blacks?
92.35%
What is the frequency of Heterozygous (Lu (a⁺b⁺)) phenotype?
7.5%
What is the frequency of Homozygous A (Lu (a⁺b⁻)) phenotype?
0.15%
What is the frequency of Null (Lu (a⁻b⁻)) phenotype?
Very Rare
What is the molecular weight of the Longer Lu Glycoprotein?
85-kD
How many amino acids does the Longer Lu Glycoprotein contain?
597 amino acids
What is the size of the cytoplasmic domain of the Longer Lu Glycoprotein?
59 amino acids
True or False: The Lutheran glycoprotein is destroyed by treatment with trypsin.
True
What type of protein is the Lutheran glycoprotein classified as?
Type q transmembrane protein
What type of antibodies are Anti-Lua and Anti-Lub primarily?
Usually IgG
Fill in the blank: Anti-Lu3 appears as inseparable ______.
Anti-Luᵃᵇ
What is the inheritance pattern of Lu(a⁻b⁻) phenotype?
- Autosomal recessive
- Autosomal dominant (In[Lu])
- X-linked recessive
What is the biological role of the Lutheran glycoprotein?
High-affinity receptor for laminin
What chromosome is the Kell gene located on?
Chromosome 7
What is the incidence of the Kell antigen K?
10%
What is the frequency of the Cellano (k) antigen?
99.8%
What is the characteristic of the McLeod phenotype?
Significantly depressed or absent Kell antigens
What is the genetic basis of the Ko phenotype?
Autosomal recessive, null phenotype
Which antibodies are clinically significant in the Kell blood group?
- Anti-K
- Anti-Kpᵃ
- Anti-Kpᵇ
- Anti-Jsᵃ
- Anti-Jsᵇ
What is the frequency of K+k- phenotype in Whites?
0.2%
True or False: Anti-K is the most common antibody seen in the blood bank after ABO and Rh antibodies.
True
What are the two Lewis antigens?
- Lewis a (Lea)
- Lewis b (Leb)
What chromosome is the Le gene located on?
Chromosome 19
What phenotype is primarily associated with non-secretors of Lewis antigens?
Le (a+b-)
What is the influence of the Se gene on Lewis antigen expression?
It is required to express the Leb antigen.
What type of cells manufacture Lewis antigens?
Tissue cells
What is the role of the Kell blood group in physiology?
Minor role in endothelin-3 homeostasis
What is the phenotype for secretors in the Lewis blood group system?
Le (a-b+)
What are the three Lewis phenotypes observed in adults?
- Le (a+b-): Non-Secretor
- Le (a-b+): Secretor
- Le (a-b-): Secretor or Non-Secretor (w or lele)
What is caused by a mutation in the Le gene?
Non-secretors and secretors with the phenotype Le (a-b-)
What antigen is present in the Le(a-b-) secretor?
Type 1 H substance: Le d
What substances are present in the secretions of individuals with the Le, Se, A/B/H genotype?
A,B,H, Le (a-b+)
True or False: Newborns show Lewis antigens immediately after birth.
False
What happens to Lewis antigen expression during pregnancy?
Antigens become weaker
At what temperature does Anti-Le a show optimum reactivity?
4°C
What class of antibody is Anti-Le a?
IgM
What is the clinical significance of Lewis antibodies?
None, does not cross the placenta, not associated with HDN
What is the most common anti-Lewis antibody encountered clinically?
Anti-Le a
What is the Duffy blood group system also known as?
ISBT NO.008
What are the Duffy antigens expressed on?
- RBCs
- Cerebellar Purkinje cells
- Post capillary venule endothelial cells
- Endothelial cells of renal glomeruli
- Epithelial cells of renal collecting tubules
- Vasa recta
- Thyroid
- Pulmonary Capillaries
- Alveolar type 1 squamous cells
What is the predominant phenotype of Duffy blood group in blacks?
Duffy Null or Fy (a-b-) phenotype
What are the common Duffy phenotypes among the White population?
49% account for heterozygous for a+ and b+
What type of antibodies are Anti-Fya and Anti-Fyb?
IgG
What is the Kidd blood group system also known as?
ISBT NO.009
What is the inheritance pattern of Kidd antigens?
Codominant allele
What clinical significance is associated with Kidd antibodies?
- Delayed hemolytic transfusion reactions
- HDN
- Intravascular hemolysis
What is the rare phenotype associated with Kidd blood group?
Jk null or Jk (a-b-)
What is the genotype of individuals with Duffy Null phenotype?
FyFy
What biological role does the Duffy Null phenotype play in malaria?
Provides resistance to Plasmodium vivax and Plasmodium knowlesi
What type of reaction does Anti-Jk antibodies commonly cause?
Delayed hemolytic transfusion reactions
What antigens are found in the Kidd blood group?
- Jka
- Jkb
- Jk3 (common)
What is the optimum temperature of reactivity for Duffy antibodies?
37 degrees Celsius
What is the association of the Duffy Null phenotype with health?
- Lower neutrophil counts
- Susceptibility to infection
- Renal disease
- Reduced graft survival following renal transplantation
What is the significance of the DARC receptor?
Facilitates leukocyte recruitment to sites of inflammation
What can cause negative results for anti-Jk antibodies in later blood samples?
Plasma dilution due to body fluids and IV solutions
After transfusion, antibodies may not be detected if diluted.
What happens following the transfusion of crossmatch-compatible Jk-positive RBCs in sensitized patients?
Brisk anamnestic antibody response with rapid in vivo hemolysis
RBCs are cleared by extravascular and intravascular hemolysis.
Why is it advised to not request a repeat crossmatching of the same blood unit?
Antibodies may not be detected on the second test due to dilution or transient disappearance
Antibodies may have an inconsistent pattern of reactivity.
What is the potential disadvantage of under-reporting antibody presence?
Possibility of transfusing incompatible blood
Over-reporting only risks delayed transfusion.
What mild condition can anti-Jk antibodies cause?
Mild hemolytic disease of the fetus and newborn (HDFN)
This is uncommon but possible.
What is the notorious reputation of anti-Jk antibodies in blood banking?
Implication in delayed hemolytic transfusion reactions
They are significant in transfusion medicine.
Which RBCs do anti-Jk3 react with?
All RBCs except Jknull
Observed in individuals with Jknull phenotype.
What is the biological role of JK/UT-B?
Facilitated transport of urea
Helps stabilize osmotic gradients in the renal medulla.
What significant change occurs in i and I antigens from birth to adulthood?
Decrease in i antigen and increase in I antigen
Transition observed by 18-24 months of age.
What is the phenotype of newborns concerning I and i antigens?
Newborns exhibit small i antigen with little big I antigen
Small i is replaced by big I over time.
What rare phenotype is associated with elevated small i antigen?
Small i adult phenotype
Found in < 1 in 10,000 donors.
What is the association of elevated small i antigen in certain conditions?
Observed in megaloblastic anemia, leukemia, and chronic hemolytic states
Indicates stressed erythropoiesis.
What are the two antibodies of the I blood group?
Anti-I and Anti-i
Both may mask clinically significant antibodies.
What type of antibody is Anti-I, and what are its characteristics?
IgM; can be benign or pathogenic
Strong reactions with adult cells, weak with cord cells.
What is the clinical significance of pathogenic Anti-I?
Causes autoagglutination and vascular occlusion
Associated with cold agglutinin disease.
What infections are associated with the production of auto Anti-I?
Infectious Mononucleosis, Mycoplasma pneumoniae, Listeria monocytogenes
Also seen in lymphoproliferative disorders.
What is the role of Anti-i antibodies?
React best with saline-suspended cells at 4 degrees Celsius
Associated with various conditions including infectious mononucleosis.
What is the Diego blood group system characterized by?
22 antigens including 3 sets of allelic antigens
Rare, low-incidence antigens present on less than 1% of donors.
What is the prevalence of Diego a (Dia) antigen among different populations?
Rare (0.01%) among whites; 54% among South Americans; 5% Chinese; 12% Japanese
Useful tool for anthropological studies.
What is the commonality of Anti-Yta and Anti-Ytb antibodies?
Anti-Yta is more common than Anti-Ytb
Suggests Yta is more immunogenic.
What is the role of AChE in the body?
Critical enzyme for the degradation of acetylcholine
Involved in neurotransmission and muscle function.
What is the Xg blood group system associated with?
Encoded by a gene on the X chromosome
Higher incidence of Xga-positive phenotype among women.
What characteristics define the Scianna blood group system?
Located on chromosome 1; associated with the ERMAP-RBC adhesion protein
Contains 7 antigens, including Sc1 and Sc2.
What are antibodies not associated with?
Hemolytic transfusion reactions or HDFN
What is the most common isotype of antibodies in the Scianna blood group system?
IgG
Where is the Scianna blood group system located?
Chromosome 1
How many antigens are in the Scianna blood group system?
7 antigens
What are the two antithetical antigens in the Scianna blood group system?
Sc1 and Sc2
What is the high-incidence antigen present on all RBCs except Sc null?
Sc3
What is the biological role of ERMAP?
Unknown, but may play a role in RBC adhesion and signaling
What is the Dombrock blood group system gene?
ART4
How many antigens are present in the Dombrock blood group system?
10 antigens
What are the high-incidence antigens in the Dombrock blood group system?
Gya, Hy, Joa, DOYA, and DOMR
What is the phenotype associated with paroxysmal nocturnal hemoglobinuria type III?
Acquired DOnull phenotype
What is the typical isotype of Dombrock antibodies?
IgG
What can anti-Dombrock antibodies cause?
Shortened RBC survival and acute and delayed hemolytic transfusion reactions
What is the gene for the Colton blood group system?
AQP1
How many antigens are there in the Colton blood group system?
4 antigens
What is the major molecular water channel on RBCs?
AQP-1
What is the gene associated with the LW blood group system?
ICAM4
What are the antigens in the LW blood group system?
LWa, LWab, and LWb
What is the biological role of LW glycoprotein?
May participate in adhesive interactions during early erythroid development
What are the genes associated with the Chido/Rodgers blood group system?
C4A and C4B
What is the characteristic of the antigens in the Chido/Rodgers blood group system?
Most are high prevalence and of plasma origin
What is the gene for the Gerbich blood group system?
GYPC
How many antigens are in the Gerbich blood group system?
11 antigens
What is the common Gerbich antibody?
Anti-Ge2
What is the biological role of GYPC and GYPD?
Maintain RBC membrane integrity through interaction with protein band 4.1
Fill in the blank: The _____ phenotype is inherited as an autosomal recessive phenotype.
[DOnull or Gy(a-)]
True or False: Anti-Dombrock is associated with HDFN.
False
What can enhance the reactivity of anti-Colton antibodies?
Protease-treated RBCs
What is the null phenotype of the LW blood group system?
LW (a-b-)
What phenomenon is associated with the absence of clinically significant hematologic sequelae in COnull individuals?
Presence of a second aquaporin, AQP-3
What is the biological role of GYPC and GYPD?
Maintain RBC membrane integrity through interaction with protein band 4.1 and p55
They help anchor the membrane to the underlying cytoskeleton
What happens to GYPC and GYPD in patients with protein 4.1 deficiency?
They are decreased
75% is normal
What is the Ge null (Leach) phenotype associated with?
Marked elliptocytosis due to reduced membrane stability and deformability of GYPC
May also bind specific P. falciparum strains
What is the gene associated with the Cromer blood group system?
CD55
Located on chromosome 1 at position 1q32
How are Cromer antigens affected by enzyme treatment?
Resistant to ficin and papain but destroyed by α chymotrypsin
Weakened with DTT treatment
How many antigens does the Cromer blood group system contain?
16 antigens
Includes 3 low-incidence antigens and 13 high-incidence antigens
What characterizes the Cromer null (Inab) phenotype?
Complete absence of all Cromer antigens
Normal expression of CD59 and other GPI-linked glycoproteins
What type of antibodies are usually associated with the Cromer blood group system?
Usually IgG
Do not cause HDFN
What is the biological role of CD55/DAF?
Complement regulating protein
Protects cells from complement by promoting the decay of C3 convertases
What is the gene associated with the Knops blood group system?
CR1
Located on chromosome 1 at position 1q32.2
How many antigens are included in the Knops blood group system?
10–12 antigens
Includes six antithetical antigens
What is the Knops null phenotype known as?
Helgeson phenotype
Kn(a-b-), McC(a-), Sl(a-), and Yk(a-)
What is the gene associated with the Indian blood group system?
CD44
Located on chromosome 11 at position 11p13
What are the two antithetical antigens in the Indian blood group system?
Inᵃ (IN1) and Inᵇ (IN2)
IN1 is a high-frequency allele
What is the primary biological role of CD44?
Major adhesion molecule on leukocytes
Binds extracellular matrix proteins
What is the gene associated with the OK blood group system?
BSG
Located on chromosome 19 at position 19p13.3
What is the main antigen in the OK blood group system?
Oka
Residing on CD147
What is the gene associated with the RAPH blood group system?
CD151
Located on chromosome 11 at position 11p15.5
What antigen is contained in the RAPH blood group system?
RAPH or MER2
Located on CD151
What is a characteristic of the MER2-negative phenotype?
Identified in individuals with nephrotic syndrome and end-stage renal disease
Associated with frameshift mutations
What type of antibodies are known in the RAPH blood group system?
Anti-MER2
Usually of IgG isotype, arising from transfusion and pregnancy
What is CD151?
A tetraspanin essential for the assembly of basement membranes in the kidney and skin, ears
CD151 plays a role in the clustering of tetraspanin and β1 integrins, important in laminin adhesion.
What are the consequences of frameshift mutations in CD151?
Renal disease and neurosensory deafness
Observed in all three patients with such mutations.
Where is CD151 widely expressed?
On:
* Epithelium
* Fibroblasts
* Endothelium
* Muscle
* Renal glomeruli and tubules
* CD34 cells
* Early erythroid precursors
* Megakaryocytes
* Platelets
What is the gene associated with the JMH blood group system?
SEMA7A, located on chromosome 15
List the antigens in the JMH blood group system.
JMH1, JMH2, JMH3, JMH4, JMH5, JMH6
How is JMH antigen expressed on cord RBCs?
Weakly expressed and destroyed by enzymes (ficin, papain, DTT)
Resistant to treatment with glycine-acid EDTA.
What happens to JMH antigen as one ages?
JMH antigen declines later in life
Where is JMH antigen found?
On:
* RBCs
* Lymphocytes
* Activated macrophages
* Thymus
* Brain
* Respiratory epithelium
* Placenta
* Testes
* Spleen
What are the variant and null phenotypes associated with JMH?
JMH weak, JMH variant, and JMH negative
An acquired, JMH weak to negative phenotype can occur in the elderly, accompanied by JMH autoantibodies.
What type of antibodies are associated with JMH?
Anti-JMH
Do not cause hemolytic transfusion reactions or HDFN, though shortened RBC survival has been documented in some patients.
What is the biological role of SEMA7A?
Semaphorin proteins are implicated in cell signaling and can modulate cellular immunity
Effects include inhibiting NK cell proliferation and stimulating chemotaxis.
What is the gene associated with the GIL blood group system?
AQP3, located on chromosome 9 at position 9p13
What is the high-incidence antigen in the GIL blood group system?
GIL
List the tissues where GIL protein is highly expressed.
On:
* RBCs
* Kidney
* Small intestine
* Stomach
* Colon
* Spleen
* Eye
* Respiratory tract
What is the biological role of AQP3?
Membrane channel capable of transporting urea on red cells
May play a role in malaria infection.
What is the RHAG gene associated with?
The RH associated glycoprotein system, located on chromosome 6
What antigens are associated with the JR blood group system?
Jra
What is the significance of the Jr(a-) phenotype?
More common in Japan
Fully developed at birth and resistant to common enzymes.
What is the gene associated with the FORS blood group system?
GBGT1, located on chromosome 9
What is the antigen in the FORS blood group system?
FORS1
What is the significance of the Lan blood group system?
Contains a high-incidence antigen expressed on ABCB6
Defects in ABCB6 have been associated with familial pseudohyperkalemia and ocular coloboma.
What is the gene associated with the Vel blood group system?
SMIM1, located at chromosome 1
What is the single high-incidence antigen in the Vel blood group system?
Vel
What is the clinical significance of Anti-Vel antibodies?
Can cause acute and delayed hemolytic transfusion reactions and HDFN
Historically considered a high-titer, low avidity antibody.
What is the gene associated with the AUG blood group system?
SLC29A1, located on chromosome 6 at position 6p.21.1
What are the antigens in the AUG blood group system?
AUG1 = null phenotype, AUG2 (Ata) = high-prevalence antigen
What is the clinical significance of Anti-Ata antibodies?
Cause severe hemolytic transfusion reactions and mild cases of HDFN
