Lutheran Flashcards
What are the Lu first?
- 1st autosomal linkage discovered in humans was Se and Lu
- 1st crossing over
- 1st unlinked dominate suppressor gene
- 1st x-linked dominate suppressor gene
- 1st blood group with 3 different backgrounds for negative phenotype
How many antigens are in Lu system?
20 antigens Lua/Lub Lu6/Lu9 High/Low Lu8/Lu14 High/Low Lu18/Lu19 = Aua/Aub
What is frequency of Lua and Lub?
Lua 8% are positive
Lub is high freq
Lub negative 0.2% of most popuations
Lu3 is present when either Lua or Lub is present
What are the characteristics of Lu antigens?
Weak on cord cells; mild or no HDFN
Present on other tissues but not plasma, PLT’s, or WBC
Fragile when stored
Resistant to papain and ficin
Destroyed by trypsin, Chymotrypsin, Pronase AET, and DTT
How does DTT/AET affect Lu antigens?
DTT and AET destroy disulfide bond IgSF that carry LU antigens
How many Lu antigens are the RBC membrane?
Number of antigens vary depending on phenotype and person. may seen MF agglutination.
Lu(a+b-) and In(Lu) only has 500 antigen sites
Lub is weakend with Lua is present
What are the characteristics of anti-Lua?
IgG, IgM, IgA, rarely binds complement
May be naturally occuring IgM
may be reactive at lower temps (18C)
Often seen MF reaction
Moslty benign antibody; rare cause of HTR
HDFN is no or milk due Lu antigen on placenta
What are the characteristics of anti-Lub?
More clinically significant that anti-Lua
mostly IgG ; rarely C’
Can cause mild HTR with jaundice and slow clearance of RBC’s
Mild HDFN
What is Anti-Lu3
IgG; rarely binds C’
Reacts with all Lua or Lub positive cells
Made by LuLu recessive people = Lu(a-b-)
How do identify anti-Lub?
DTT destroys (also Detroys Kell, JMH, DO, and KN)
What are the characteristics of Lu 4-20 antigens?
NOt fully developed at birth
Resistant to ficin and papain
Sensitive to DTT and AET
Relatively few reports of each antibody specificity
What is the LuLu phenotype?
Recessive inheritance of 2 Lu null gene
Very rare
No Lu antigens = make anti-Lu3
Red cells will not adsorb/elute Lu antibodies
What is the In(Lu) dominate inhibitor?
In(Lu) is a DOMINATE gene located at another locus that inhibits Lu antigen expression
Caused by mutation in KLF1 gene
May see abnormal RBC morph = acantocytes
Can absorb/elute Lu antibody = small amt of antigen
Homozygous inheritance is not compatible with life
What other antigens are weakend in the In(Lu) phenotype?
P1, i, IN (CD44), AnWj, Knops, Csa, MER2
Think of family studies if parents are typing as P1 negative and child types as P1 positive. Its because parents P1 was suppressed. Child inherited normal Lu and P1 gene and expressed both.
What is the Lu(mod) x linked inhibitor?
Mutation in GATA-1 an x linked transcription factor
Causes Lu(a-b-) phenotype but Lub can be absorbed and eluted off
Found in Males
RBC have weak P and I but increased i
