136 Erythrocyte Antigens and Antibodies Flashcards
(101 cards)
1
Q
Most of the protein blood group antigens are carried on
A
Integral transmembrane proteins (either single-pass type I or type II, or multipass)
A few are carried on glycosylphosphatidylinositol (GPI)-linked proteins or adsorbed from plasma
2
Q
Chromosome Location of ABO Blood Group
A
9q34.2
3
Q
Blood Group System: Decreased Plasmodium falciparum invasion, may be receptor for Escherichia coli
A
MNS
4
Q
Blood Group System: Possibly transports CO2 or NH3 (CD240)
A
Rh
5
Q
Blood Group System: Increased expression possibly involved in vasoocclusion in sickle cell disease
A
Lutheran
6
Q
Blood Group System: Cleaves big endothelin-3 to ET-3, a potent vasoconstrictor (CD238)
A
Kell
7
Q
Blood Group System: Increased expression in fucosidosis, antibodies may be important in graft rejection
A
Lewis
8
Q
Blood Group System: Resistance to P vivax invasion
A
Duffy
P. falciparum: MNS
9
Q
Blood Group System: Urea transporter; Impaired urea transport, urine-concentrating defect
A
Kidd
10
Q
Blood Group System: Anion exchanger
(CD233), Band 3 cytoskeletal protein; Southeast Asian ovalocytosis, hereditary spherocytosis, renal tubular acidosis
A
Diego
11
Q
Blood Group System: Absent from PNH III RBCs
A
Yt
Dombrock
12
Q
Blood Group System:Monosomy 7, inability to
maximally concentrate urine, congenital dyserythropoietic anemia
A
Colton
13
Q
Blood Group System: Renal disease, associated with pretibial epidermolysis bullosa and sensorineural deafness
A
Raph
14
Q
Blood Group System: Acanthocytosis, muscular dystrophy, hemolytic anemia; McLeod syndrome sometimes associated with CGD, peripheral neuropathy, cardiomyopathy seizures, a late-onset dementia, and behavioral changes
A
Kx
15
Q
Blood Group System: Hereditary elliptocytosis, hemolytic anemia, decreased 4.1R and p55
A
Gerbich
16
Q
Blood Group System: Absent from PNH III RBCs, Dra is the receptor for uropathogenic E coli
A
Cromer
***John Milton Hagen, CD59 (also absent from PNH III RBCs)
17
Q
Blood Group System: Congenital cataracts in Asians
A
I
18
Q
Blood Group System: Receptor E coli and parvovirus B19
A
GLOB
19
Q
Blood Group System: Hemolytic anemia, hereditary stomatocytosis
A
Rh-associated glycoprotein
20
Q
Blood Group System: Multiple small calcifications around the joints in the hand and ectopic calcification or mineralization in hips, feet, pubic symphysis, and lumbar discs
A
Augustine
21
Q
Blood Group System: Expressed on Tamm-Horsfall glycoprotein in urine that prevents adherence of pathogenic bacteria to urothelial cells
A
Sid
22
Q
Blood Group System: Deafness, choline deficiency disease
A
CTL2
23
Q
As of this writing, ____ blood group systems and _____ antigen collections are defined
A
39 blood group systems
5 antigen collections
24
Q
Most significant antigens in transfusion and
transplantation
A
ABO
Because A and B antigens also are expressed on most tissue cells, ABO compatibility is a significant consideration in solid-organ transplantation.
25
Most significant antigen after A and B
D
## Footnote
The antigens C, c, E, and e are less immunogenic
26
Important cause of DHTR
Kidd
27
# TRUE OR FALSE
Group A or B erythrocytes appear to have less H antigen than group O cells
TRUE
Group A or B erythrocytes appear to have less H antigen than group O cells
## Footnote
The sugars defining A and B antigens are added to carbohydrate chains carrying the H antigen (fucose), which is “hidden” by the A (GalNAc) or B (Gal) sugar.
28
# TRUE OR FALSE
Because A and B antigens also are exclusively expressed on RBCs, ABO compatibility has no role in solid-organ transplantation.
FALSE
Because A and B antigens also are expressed on most tissue cells, ABO compatibility is a significant consideration in **solid-organ transplantation.**
29
ABO incompatibility only rarely causes severe HDFN because antibodies directed against A and B antigens are predominantly immunoglobulin (Ig) ______, which do not cross the placenta
Immunoglobulin (Ig) M
30
The **second most important blood group system** in transfusion medicine because antigen-positive RBCs frequently immunize antigen-negative individuals through transfusion and pregnancy.
Rh system
31
Inheritance of **Rh antigens** is determined by a complex of two closely linked genes:
* Protein-carrying D antigen (RhD)
* Protein carrying C or c and E or e antigens (RhCE)
32
In the Rh system, _______ common antigen combinations or haplotypes are possible
Eight
33
Approximately_____% of the **white** population is Rh-positive, and _____% is Rh-negative.
85% Rh-positive
15% Rh-negative
34
A substance that can evoke an immune response when introduced into an immunocompetent host and react with the antibody produced from that immune response.
Antigen
35
The ability of an antigen to **stimulate an immune response** is called
Immunogenicity
36
Ability to react with an antibody
Antigenicity
37
# TRUE OR FALSE
Immunogenicity does not always correlate with the hemolytic potential of an antibody specificity
TRUE
Immunogenicity does not always correlate with the hemolytic potential of an antibody specificity
## Footnote
For example, K is more immunogenic than Jk a but anti-Jk a is more likely to cause hemolysis.
38
Order of immunogenicity
A and B, D, K
39
A, B, and H antigens can be detected at ______ weeks of gestation
5 to 6 weeks of gestation
40
Full expression of A, B, H, I, and Lewis antigens usually is present by age____ years, whereas full expression of P1 and Lutheran antigens may not occur until age ______years.
3 years
7 years
41
Examples of Carbohydrate Antigens:
* ABO
* H
* I
* LE
* P1PK
* GLO
* Sd
42
Protein structures that carry blood group antigens can be grouped into three categories:
(1) those that make a single pass through the erythrocyte membrane,
(2) those that make multiple passes through the membrane, and
(3) those that are attached to the membrane through a covalent linkage to lipid (GPI-linked).
43
Defective synthesis of the ________ is responsible for paroxysmal nocturnal hemoglobinuria (PNH)
GPI anchor
44
# TRUE OR FALSE
Protein antigens are direct gene products
Carbohydrate antigens, made by transferase action, are indirect gene products.
TRUE
Protein antigens are direct gene products
Carbohydrate antigens, made by transferase action, are indirect gene products.
45
Most blood group genes are located on autosomes; only two, _____________, are located on the X chromosome
Xg and XK
46
Blood group systems are present **only on RBCs**
Antigens in the RH and JK blood group
| RJK exclusive in RBC
47
**ABH** antigens have broad tissue distribution.
In embryos, A, B, and H antigens are detectable on all endothelial cells and all epithelial cells except those of the _______.
CNS
48
Antigens that are present in **plasma** and on **platelets** and **lymphocytes**
ABO, P1PK, LE, H, and I systems
| ABHI will take the PLE and will ace topics on plasma, platelets and lymp
## Footnote
ABH on platelets and lymphocytes may be acquired at least in part by adsorption from plasma.
**Secretions** (saliva, milk, sweat, semen, and urine, **but not cerebrospinal fluid**) contain soluble **A, B, H, I, and Le a and Le b** antigens but **no P1PK or GLOB** system antigens.
49
**Granulocytes** carry _____ antigen but **no ABH**
I antigen
| GI strong without ABO
50
**Sd** a antigen is found in most **body secretions**, with the greatest concentration in____________.
Urine
51
Blood group more common in persons with cancer of the salivary glands, stomach, colon, or ovary, and with thrombosis (because of higher levels of coagulation factors VIII, V, and IX)
Blood group A
52
Blood group more common in patients with duodenal and gastric ulcers, rheumatoid arthritis, and von Willebrand disease.
Blood group O
53
Blood group more common in patients with Escherichia coli urinary tract infection, gonorrhea
Group B
54
Blood group more common in patients with Sjögren syndrome
Le(a–b–)
55
Blood group more common in patients with Helicobacter pylori
Group O, Le(a–b+)
56
Blood group more common in patients with Parvovirus
Globoside
57
Blood group with resistance to Pyelonephritogenic infections of E. coli, parvovirus B
p (PP1Pk–)
58
Blood group with resistance to Plasmodium vivax, Plasmodium knowlesi
Fy(a–b–)
59
Blood group with resistance to Plasmodium falciparum
Tn–, Cad–, En(a–), U–, Ge–
60
Blood group associated with antibody production in Cold agglutinin disease
Anti-I, -IH, -i, -H, -Pr
61
Blood group associated with antibody production in Warm autoimmune hemolytic anemia
Anti-“Rh,” –“Kell,” -U, -Wr
62
Blood group associated with antibody production in Mycoplasma pneumoniae, chronic lymphocytic leukemia, Hodgkin lymphoma and non-Hodgkin
lymphomas
Anti-I
63
Blood group associated with antibody production in Infectious mononucleosis, reticuloendothelial diseases
Anti-i
64
Blood group associated with antibody production in Early spontaneous abortions
Anti-PP1P
65
Blood group associated with antibody production in Paroxysmal cold hemoglobinuria, early spontaneous abortions, lymphoma
Anti-P
66
Blood group associated with antibody production in Renal dialysis (formaldehyde exposure)
Anti-NF
67
Blood group associated with antibody production in Virally induced hemolysis
Anti-Rx
68
The critical receptor for P. vivax attachment
Fy6 antigen
## Footnote
Erythrocytes **lacking Fy a and Fy b antigens** are not infected by the malarial parasite **Plasmodium vivax** or by the simian malarial parasite **Plasmodium knowlesi**
69
Phenotype is associated with hereditary **stomatocytosis**, hemolytic anemia (usually mild and well compensated)
Rh null Syndrome
Most Rh null red cells are stomatocytes, or occasionally spherocytes, and demonstrate increased osmotic fragility, increased potassium permeability, and higher potassium pump activity.
70
Individuals have **acanthocytosis**, decreased RBC survival, very weak expression of **Kell** blood group antigens, lack of **Kx** antigen on RBCs, and a well-compensated hemolytic anemia.
McLeod Phenotype
## Footnote
RBCs with the McLeod phenotype show a defect in water transport, increased mobility of phosphatidylcholine across the membrane, and increased phosphorylation of protein band 3 and β-spectrin.
71
Rare people **lack A, B, and H antigens** and have naturally occurring anti-A, anti-B, and anti-H in their plasma.
Without Fuc, neutrophils **lack sialyl Le X** and thus cannot roll and ingest bacteria.
Has condition that is called **leukocyte adhesion deficiency II** or **congenital disorder of glycosylation II**
Bombay (O h ) Phenotype
## Footnote
All cells lack Fuc
These patients have a high white blood cell count and severe recurrent infections.
72
Alloantibodies:
Autoantibodies:
**Alloantibodies**: only react with antigens present on the RBCs of other people
**Autoantibodies**: react with self-antigens present on the patient’s own RBC
## Footnote
Alloantibodies also can be classified according to their mode of sensitization as **naturally occurring** (no apparent sensitization) or **immune** (after sensitization).
73
The predominant antibody made in an immune response and constitutes approximately 80% of total serum Ig
IgG
## Footnote
Most IgG antibodies sensitize RBCs at 37 °C and are detected with an antiglobulin reagent
IgG blood group antibodies also are capable of fixing **complement**, although some subclasses do so less efficiently than others: **IgG 3** > IgG 1 > IgG 2 > IgG 4
74
A **pentamer** of five basic units (having μ heavy chains plus a short J, or joining, chain) and makes up only approximately 4% of total serum Ig
First class of Ig produced by the fetus and is the predominant antibody in a primary immune response, but it does not cross the placenta
Because of their pentameric structure, even low-affinity IgM blood group antibodies can **agglutinate** RBCs and **activate complement**.
IgM
## Footnote
IgM antibodies of low affinity may agglutinate RBCs only at temperatures **below 37 °C**.
Because such IgM antibodies dissociate from RBCs at higher temperatures, their reactivity may be detected in routine antiglobulin tests (using polyspecific antiglobulin) by virtue of the complement components that remain bound to the red cell membrane.
75
The primary Ig in **body secretions**, where it exists predominantly as a **dimer** with a secretory component
IgA
## Footnote
Does not cross the placenta or fix complement, but aggregated IgA can activate the alternative pathway of complement, and IgA can trigger cell-mediated events
76
IgG levels rise significantly between _________ weeks of gestation as a selective transport system matures and maternal IgG is actively transported across the placenta.
20 and 33 weeks of gestation
77
Anti-A and anti-B usually are readily detected by age_________ months.
2 to 6 months
78
Blood bank standards testing on neonates younger than 4 months
The **mother’s serum** is used (and preferred) for identifying antibodies in a newborn and for crossmatching RBC components
79
**Naturally occurring alloantibodies** are commonly associated with the **carbohydrate** antigens of the _______________blood group systems.
ABO, H, LE, and P1PK blood group systems
80
Most naturally occurring antibodies are _______
IgM
81
# TRUE OR FALSE
Except for anti-A and anti-B, most common naturally occurring antibodies do not react at body temperature and are considered clinically insignificant.
TRUE
**Except for anti-A and anti-B**, most common **naturally occurring antibodies** do not react at body temperature and are considered **clinically insignificant.**
82
Immune antibodies are produced after exposure to foreign RBC antigens through:
Pregnancy or transfusion
## Footnote
**Immune antibodies are found more commonly in individuals who have been multiply transfused than in multiparous women**
This situation occurs because in pregnancy the immunizing dose of red cells often is too small to elicit a primary response and the foreign antigens are limited to those of the father.
83
Immune antibodies most often are
IgG
## Footnote
But may be IgM and sometimes are IgA
84
Antibodies that disappear after several months and are more commonly associated with d**elayed hemolytic transfusion reactions**
Kidd
85
The most common alloantibodies
Anti-C, anti-E, and anti-K
86
The most potent cause of immediate hemolytic reactions
ABO incompatibility
## Footnote
Because A and B antigens are strongly expressed on RBCs and the antibodies so efficiently bind complement.
The severity of the reaction varies with antigen density and antibody characteristics.
87
Antibodies commonly associated with **intravascular hemolysis**:
Anti-A, anti-B, anti-Jka, and anti-Jkb
88
Antibodies commonly associated with **extravascular hemolysis**:
Rh, Kidd, Kell, Duffy, or Ss antigens
## Footnote
Occurs with **IgG1 and IgG3** antibodies that react at body temperature
89
Most commonly seen HDFN
ABO HDFN
## Footnote
Clinically mild, presumably because the antigens are not fully expressed at birth
90
Cause severe HDFN, and fetal health should be carefully monitored when anti-D titers are greater than **16**
D antigen
91
# AHA Antibodies
Warm autoantibodies:
Cold-reactive autoantibodies:
Paroxysmal cold hemoglobinuria (“Donath-Landsteiner” antibody:
Warm autoantibodies: **Rh** protein, Wrb, Kell, Kidd, and U
Cold-reactive autoantibodies: **anti-I** , i, H, Pr, P
Paroxysmal cold hemoglobinuria (“Donath-Landsteiner” antibody: antigen P (GLOB)
92
The single most important test performed in the transfusion service because it is the fundamental basis for determining blood compatibility
ABO
## Footnote
The D type is the next most important test performed for blood compatibility.
93
Testing RBCs with licensed antisera to identify the A or B antigens they carry
Forward, or cell, grouping
94
Testing the corresponding serum or plasma with known A and B cells to identify the antibodies
Reverse, or serum, grouping
95
If the ABO group of a patient cannot be determined, group ______ blood can be used for transfusion
Group O blood
96
# TRUE OR FALSE
Donors with weak D antigen are considered Rh-positive.
TRUE
Donors with weak D antigen are considered Rh-positive.
97
Detects **“atypical” or “unexpected” antibodies** in the serum (ie, other than anti-A and anti-B) using **group O reagent red cells** that are known to carry various combinations of antigens
Antibody screen, or indirect antiglobulin test
## Footnote
The antibody screen will not detect all atypical antibodies in serum, such as antibodies to low-prevalence antigens not present on screening cells and antibodies that are not apparent at 37 °C and in the antiglobulin phase.
98
A test detects antibody or complement bound to RBCs in vivo
Direct antiglobulin test (often referred to as the direct Coombs test
## Footnote
Positive direct antiglobulin test results are associated with the following:
* (a) transfusion reactions, in which recipient alloantibody coats transfused donor RBCs or transfused donor antibody coats recipient RBCs;
* (b) HDFN, in which maternal antibody crosses the placenta and coats fetal RBCs;
* (c) autoimmune hemolytic anemias, in which autoantibody coats the patient’s own RBCs;
* (d) drug or drug–antibody complex interactions with RBCs that sometimes lead to hemolysis;
* (e) passenger lymphocyte syndrome, in which transient antibody produced by passenger lymphocytes from a transplanted organ coats recipient RBCs; and
* (f) hypergammaglobulinemia, in which Ig nonspecifically adsorb onto circulating RBCs.
**A positive direct antiglobulin test result does not always indicate decreased red cell survival.**
99
Refers to a set of donor and recipient tests that are performed before red cell transfusion
Compatibility testing
## Footnote
Routine recipient testing includes an **ABO, D, and antibody screening** on a blood sample collected within **three days** of the intended transfusion.
**Repeat donor testing and crossmatching are not performed for plasma and platelet components**, but the **recipient’s ABO and Rh phenotypes must be known** for appropriate selection of components.
100
# TRUE OR FALSE
The chance of finding compatible units usually reflects the antigen prevalence in the population.
TRUE
The chance of finding compatible units usually reflects the antigen prevalence in the population.
101
A panel of 8 to 16 different group O red cells that have been typed for antigens corresponding to clinically significant antibodies
Antibody identification
## Footnote
Absence of reactivity with autologous cells implies the antibody is an alloantibody, whereas a positive result suggests autoantibody or a positive direct antiglobulin test result
