OTHER BLOOD GROUP SYSTEMS PART 3 (LU) Flashcards
• (?) were first recognized in 1945 when (?) was discovered in a patient with lupus erythematosus diffusus after receiving a transfusion with blood carrying the low-incidence antigen.
Lutheran antigens
anti-Lua
was misinterpreted as Lutheran, derived from the donor’s name Luteran
• Anti-Lua
Subsequently, [?], the antithetical partner to Lua, was described in 1956.
anti-Lub
was described in 1961, demonstrating dominant inheritance, contrary to most null phenotypes at the time.
Lu(a-b-)
inherited as a recessive silent allele was identified.
Lu(a-b-)
were used to test antibodies to unknown high-incidence antigens.
Rare Lu(a-b-) RBCs
Some sera showed a phenotypic relationship to Lutheran, reacting with all RBCs except
Lu(a-b-)
These specificities were given numeric designations (?) to represent their association with the Lutheran system.
Lu4, Lu5, Lub, etc.
Three pairs of antithetical antigens (?) have been shown to be inherited at the Lutheran locus.
Lu6 and Lu9, Lu8 and Lu14, Lu18 and Lu19
Several antigens have been shown to be located on the Lutheran glycoprotein, while three antigens (?), often referred to as para-Lutheran, have limited evidence of belonging to the Lutheran system.
Lu11, Lu16, Lu17
• The ISBT designation of the Lutheran blood group system is
LU or 005.
• Allelic Codominant Genes: are, produced by allelic codominant genes.
Lua and Lub antigens
• Common Phenotypes: Most individuals express[?], while [?] phenotype is less common.
Lu(b)
Lu(a)
• Variable Expression: expression varies between individuals and even within an individual’s RBCs.
Lutheran antigen
strength has been confirmed to have low density
and variable expression.
Lub antigen
• Development: Antigens have been detected on fetal RBCs as early as [?], but they are poorly developed at birth and reach adult levels by age 15 years.
10 to 12 weeks of gestation
• Distribution: have not been found on platelets, lymphocytes, monocytes, or granulocytes.
Lutheran antigens
is widely distributed in tissues such as the brain, lung, pancreas, placenta, skeletal muscle, and hepatocytes, especially fetal hepatic epithelial cells.
Lutheran glycoprotein
Type: Most examples are IgM naturally_ occurring saline agglutinins. Some may also be IgA or IgG.
•Anti-Lua
Reactivity: They typically react better at room temperature than at 37°C, although some may react at 37°C by indirect antiglobulin test
Anti-Lua
are capable of binding complement, but in-vitro hemolysis has not been reported.
Anti-Lua
• Detection: often goes undetected in routine testing because most reagent cells are Lu(a).
Anti-Lua
It is more likely encountered as an incompatible crossmatch or during an antibody workup for another, specificity.
Anti-Lua
Experienced technologists recognize Lutheran antibodies by their characteristic loose, mixed-field reactivity in a test tube.
Anti-Lua
Effect of Enzymes: is not profoundly altered with common blood bank enzymes such as ficin and papain, but it can be destroyed with trypsin, chymotrypsin, pronase, AET, and DTT.
Anti-Lua
Most are clinically insignificant in transfusion.
Anti-Lua
There is one report of normal or near-normal survival of Lu(a) RBCs in a patient with
Anti-Lua
Immediate transfusion reactions due to are undocumented, and delayed reactions are rare and mild.
Anti-Lua
Hemolytic Disease of the Newborn (HDN): Because Lutheran antigens are poorly expressed on cord RBCs, cases of HDN associated with [?] are mild.
Anti-Lua
Infants may exhibit weakly positive or negative direct antiglobulin tests and mild to moderate elevations in bilirubin.
Anti-Lua
Many require no treatment, while others respond to simple phototherapy.
Anti-Lua
In one report of mild HDN, the mother’s antibody titer rose to 4096.
Anti-Lua
Although the first example of [?] was a room-temperature agglutinin, most [?] is gG and reactive at 37°C at the antiglobulin phase.
Anti-Lub
IgM and IgA antibodies have also been noted.
Anti-Lub
It is primarily made in response to pregnancy or transfusion.
Anti-Lub
reacts with all cells tested except the auto-control, and reactions are often weaker with Lu(a-b-) RBCs and cord RBCs.
Alloanti-Lub
Ficin or papain does not significantly alter reactivity.
Anti-Lub
AET or DTT should destroy Lub antgen through disruption of the disulfide bond of the glycoprotein, but this may require optimal conditions.
Anti-Lub
Autologous RBCs will test [?] if typing sera are available.
Lu(a)
has been implicated with shortened survival of transfused cells and post-transfusion jaundice, but severe or acute hemolysis has not been reported
Anti-Lub
Chromium survival studies demonstrate a rapid initial clearance of some Lu(b-) RBCs but much slower removal of those remaining
Anti-Lub
may be regarded as clinically significant, but blood should not be withheld in emergency situations just because compatible units cannot be found
Anti-Lub
is associated with only mild cases of HDN.
anti-Lua, anti-Lub
This type of Lu(a-b-) phenotype is the result of a rare dominant regulator gene, which suppresses the expression of Lutheran antigens.
• Dominant In(Lu) Type
Blood donor screenings have shown the frequency of this type of Lutheran null to be relatively rare.
• Dominant In(Lu) Type
Individuals with this phenotype do not make anti-Lu3.
• Dominant In(Lu) Type
In some families, the Lu(a-b-) phenotype demonstrates recessive inheritance, resulting from having two rare silent alleles at the Lutheran locus.
• Recessive Lulu Type
Individuals with this phenotype truly lack all Lutheran antigens and can make an inseparable anti-Luab called anti-Lu3.
• Recessive Lulu Type
This rare Lu(a-b-) phenotype, observed in a large Australian family, is thought to be the result of an X-borne inhibitor to Lutheran.
• Recessive X-Linked Inhibitor Type
All Lu(a-b-) family members were male and carried trace amounts of Lub detected by adsorption-elution.
• Recessive X-Linked Inhibitor Type
Lu(a-b-w) individuals with weakened Lutheran antigens, also known as Lu(w), may result from In(Lu) with a lesser degree of penetrance or an allele to In(Lu) that causes less suppression.
• Lu(w) Phenotype
is a rare antibody that reacts with all RBCs except those testing Lu(a-b-).
Anti-Lu3
It is usually antiglobulin-reactive.
Anti-Lu3
This antibody is made only by Lulu individuals, i.e., the recessive type of Lu(a-b-).
Anti-Lu3
It is associated with only mild cases of HDN.
Anti-Lu3
RBCs from dominant and X-linked type Lu(a-b-) individuals can be safely transfused to patients with anti-Lu3.
Anti-Lu3
Other Lutheran Antigens:
• Lu4, Lu5, Lu7, Lu12, Lu13, and Lu20
• Lu11. Lu16, and Lu17
are antigens of very high incidence that are absent from Lu(a-b-) RBCs.
• Lu4, Lu5, Lu7, Lu12, Lu13, and Lu20
They are located on the Lutheran glycoprotein and have not been shown to be inherited at the Lu locus.
• Lu4, Lu5, Lu7, Lu12, Lu13, and Lu20
are high-incidence antigens phenotypically related to Lutheran but have not been shown to be located on the Lutheran glydoprotein nor have they been shown to be inherited.
• Lu11, Lu16, and Lu17
The Lutheran (Lu) system comprises two major antigens, [?], giving rise to four possible phenotypes:
Lu(a+b-), Lu(a+b+), Lu(a-b+), and Lu(a-b-).
Lua and Lub
Among these, [?] is the most common phenotype.
Lu(a-b+)
• The genes encoding for the Lu antigens are linked to the
Se (secretor) genes
• Both antibodies are rare.
anti-Lua, and anti-Lub
react best at 37°C and often give a mixed field agglutination reaction
Lua
react best at 37°C in the antiglobulin phase of testing.
Lub
can cause mild hemolytic transfusion reactions (HTR), but they only rarely cause mild hemoiytic disease of the newborn (HDN)
• Lu antibodies
[?] are often naturally occurring, while [?] typically develop after RBC stimulation by transfusion or pregnancy.
Lua antibodies
Lub antibodies
may manifest as a naturally occurring saline agglutinin that reacts optimally at room temperature.
• Anti-Lub
is typically an IgG antibody reactive at the antiglobulin phase
• Anti-Lub
usually produced in response to foreign RBC exposure during pregnancy or transfusion.
• Anti-Lub
is rare and may result from three different genetic backgrounds, including dominant In(Lu) type, recessive Lulu type, and recessive X-linked inhibitor type
Lu(a-b-)
