Kell,Lutheren,HLA Flashcards
What antigens make up the Kell group? (6)
- K
- k
- Kp(a)
- Kp(b)
- Js(a)
- Js(b)
Where are Kell antigens expressed?
-What are alloantibodies capable of?
Mature RBCs and Erythroid precursors
-Suppressing erythropoiesis
The Kell antigens are expressed in covalent association with what antigen?
Kx antigen
What is the relative prevalence of K(KEL1), Kp(a), and Js(a)?
- K(KEL1) - 9%
- Kp(a) - 2%
- Js(a) - 0.1%
Which Kell antigens are found in high frequency (99% of donors)
- k
- Kp(b)
- Js(b)
What is k antigen also known as?
Cellano or KEL2
The Kell null phenotype results from what?
-What do RBCs express?
Homozygous inheritance of the amorph K0
-RBCs have no Kell antigens but have an abundance of Kx
McLeod phenotype:
- Gene mutation
- Inheritance
- RBC finding
McLeod phenotype:
- Kx encoding (XK) gene
- X-linked Recessive
- RBC show Acanthocytosis
The McLeod phenotype is frequently associated with what other diseases? (3)
- Chronic Granulomatous disease
- Muscular Dystrophy (late onset type; “neuroacanthocytosis”)
- Retinitis Pigmentosa
Anti-K antibodies:
- temp
- class
- acquisition
Anti-K antibodies:
- Warm
- IgG
- Acquired through exposure
Kell antigens are ________ by enzymes.
Unaffected
Kell antigen expression is diminished by agents that dissolve what bonds?
-Very sensitive to? (3)
Sulfhydryl bonds
- 2-mercaptoethanol
- ZZAP
- Dithiothrietol (DTT)
Kell related HDFN is characterized by what?
Suppression of erythropoiesis
Lutheran Antigens - Incidence.
-What are the phenotypes?
Lu(b) - High (99%)
Lu(a) - 7%
Lu(a-b+) - 93%
Lu(a+b+) - 7%
Lutheran antigen expression is increased on the surface of what type of RBCs?
Sickle Cells
Lutheran antigeniticity is ______ by enzymes.
Destroyed
What else destroys Lutheran antigenicity?
- 2-ME
- DTT
Lutheran antibodies:
- Specificity to
- Temp
- Class
- Clinical significance
Lutheran antibodies:
- Anti-Lu(a)
- Cold
- IgM
- Insignificant
What type of a reaction is a typical feature of Lutheran antibodies?
Mixed Field
Where is HLA encoded?
Major Histocompatibility complex (MHC)
-chr6p
MHC consists of what genes?
MHC
- class I
- class II
- class III
MHC class III genes encode for what?
Complement proteins
What is also embedded in the MHC region? (3)
- HFE gene
- 21-hydroxylase gene (CAD)
- TNF gene
Class I genes encode for HLA class I antigens:
- What cells
- Distributed among what 3 loci
- Surface of ALL cells
- HLA-A, HLA-B, HLA-C
HLA class I genes encode a single polypeptide chain that is… (2)
- Embedded as a transmembrane protein
- Noncovalently associated with a single molecule of a2-microglobulin
Young RBCs express class I antigens but lose them as they age, what is the exception?
Bg (Bennet Godspeed) Antigens
-Strongly expressed on Mature RBCs
*Rarely cause HTR
What are the major Bg antigens? (3)
- Bga (HLA-B7)
- Bgb (HLA-B17)
- Bgc (HLA-A28/A2)
T/F: Platelets have a generous amount of class I antigens.
True
Class II genes encode class II antigens:
- What cells (3)
- What 3 loci
- B-cells
- Macrophages
- Activated T-cells
HLA-DR
HLA-DP
HLA-DQ
Class II genes encode what?
2 polypeptide chains (alpha/beta)
- Each with 2 domains similar to the Ig light chains
- Transmembrane protein
T/F: Class II antigens are expressed on RBCs and Platelets.
FALSE
HLA plays a small role in RBC compatibility but is pivotal in what situations? (3)
- Platelet refractoriness
- Solid organ compatilibity
- Transfusion reactions (Febrile, TRALI, TAGVHD)
Since each MHC comple is closely linked and inherited en bloc, each parental chromosome can be thought of as a haplotype. One hyplotype is inherited from each parent.
- What is the chance that 2 siblings are HLA identical?
- What is the chance if you have 2,3 siblings?
25%
- 2 siblings - 45%
- 3 siblings - 60%
