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Agriculture1-troy

Henry

QuestionAnswer
The minimum hemogloblin concentration in a fingerstick from a male blood donor is: All donors, regardless of sex, require a minimum of hgb of 12.5 g/dL (125g/L). The value must not be performed on an earlobe stick.
A cause of permanent deferral of blood donation is: A history of jaundice of uncertain cause. Jaundice is a sign of liver impairment, which might be due to HBV or HCV. Infction with HBV and HCV is a cause for indefinite deferral.
Which of the following prospective donors would be accepted for donation? The receipt of blood products is a 6 month deferral, the deferral for travel to areas endemic for malaria is 12 months regardless of antimalarial prophylaxis, ans a peron taking antibiotics may have bacteremia. The requirement for temperature is not over
Which one of the following constitutes permanent rejection status of a donor? A positive test for HBsAg at any time is an indefinite deferral
According to AABB standards, which of the following donors may be accepted as a blood donor? A woman who had a spontaneous abortion at 2 months of pregnancy, 3 months previously would be acceptable. A donor is acceptable if she has not been pregnant in the previous 6 weeks
Generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. Hyaline casts
Which type of spectrophotometric blank should be used to account for absorbance differences caused by the specimen being tested: The serum blank is used to eliminate absorbance caused strictly by variations in the patients serum.
The Western Blot Assay is used as a confirmatory test for which of the following: Western blot testing is the gold standard for anti-HIV-1 confirmation.
Eosinophilia is commonly found in which of the following disorder(s): Eosinophilia is most commonly seen as a result of allergic reactions, medication reactions and parasitic infections.
To detect the presence of blocking antibodies fixed on the red cells of a newborn infant: Use the direct antiglobulin test
Which of the following parasites is not commonly found in the peripheral blood: Onchocerca volvulus. The microfiliariae of Onchocerca do not generally circulate in the peripheral blood. The diagnosis is made by demonstrating the microfiliariae in teased skin snips
Standard precautions means that: All specimens must be handled as if they are hazardous and infectious. According to the CDC, Standard Precautions must be used for the care of all patients, regardless of their diagnosis or presumed infection status. "Standard Precautions apply to 1)
Which of the following is used primarily for the treatment of manic-depression: Lithium is commonly used in the treatment of manic depressive patients. Lithium exerts a dual effect on receptors for the neurotransmitter glutamate; acting to keep the amount of glutamate active between cells at a stable, healthy level, neither too much
Which of the following procedures would you employ to monitor the precision of an assay: Run samples in duplicate. Precision is a measure of reproducibility of a test when it is repeated several times under the same conditions. It could be monitored by running samples in duplicate or triplicate.
Which of the following would not be detected by means of a major crossmatch: Misgrouping a group A patient as a group O
Which of the following methods would be employed to collect sweat for chloride analysis: Iontophoresis is the gold standard for the collection of sweat for sweat chloride analysis. Pilocarpine iontophoresis actually stimulates the production of sweat. Equal to or less than 39 mmol/L = Cystic Fibrosis is not likely to be present (rules-out CF
CPT (Current Procedural Terminology) codes: Provide a uniform method of coding medical, surgical, and diagnostic services
Which of the following statements about synovial fluid is true? Patients with gout involving joints will have markedly elevated neutrophils in their synovial fluid
Which of the following would you expect to find in the serum of a patient who has recovered from Hepatitis B infection within 6 months after infection? The anti-Hbs antibody is produced in response to HBV surface antigen. The anti-Hbs levels in the blood of patient who are infected with hepatitis B will rise during the recovery phase. This test in the laboratory is used to detect previous exposure to HBV
Which of the following RBC indices is expressed in femtoliters? MCV is the average volume of the RBC expressed as femtoliters or as cubic micrometers.
There is a broad based increase in the gamma band, corresponding to polyclonal hypergammaglobulinemia, as seen in chronic inflammation
The main purpose of using deglycerolized red cells is to: Prevent reactions in patients with antibodies to a high incidence antigen
Elevation in conjugated bilirubin is most likely to be found in which of the following conditions: Posthepatic jaundice is the result of bile duct obstruction, not impaired hepatic function. It will result in elevation of direct (conjugated) bilirubin.
The measurement of total glycosylated hemoglobin A1c is an effective means of assessing the average blood glucose levels: Over the past 2-3 months The concentration of hemoglobin A1c is directly proportional to the average plasma glucose level that the RBCs are exposed to during their 120 day life span.
The glycosylated hemoglobins result from glycosylation of serine, asparagine, and hydroxylysine residues in hemoglobin.
There are three glycosylated hemoglobins: Hb A1a, Hb A1b, and Hb A1c, of which Hb A1c constitutes 80%. Most methods measure total gycosylated hemoglobin, which has a high degree of correlation to Hb A1c, and may be reported as such after making the appropriate conversion.
Which factor(s) are important to consider in the validation of test results on acutely intoxicated patients: Condition of the specimen Quantity of specimen available Timing of the specimen Type of specimen submitted
Ionized calcium is most commonly measured using which of the following method: Ion Selective Electrodes, or ISEs, are the most common methodology used to detect calcium in various laboratory instruments. A calcium ISE has a PVC membrane, which is impregnated with an organic molecule that selectively binds and transports Ca++ ions
Which of the following patients represents an acceptable donor. With certain exceptions, blood donors must be at least 17, must have a hematocrit of at least 38%, must have a blood pressure no greater than 180 systolic, and no greater than 100 diastolic. Their pulse must be regular and between 50 and 100 beats per min
Howell-Jolly bodies are composed of: DNA Howell-Jolly bodies are residual fragments of DNA within erythrocytes. They may be seen in pernicious anemia and thalassemias.
Which one of the following organisms is sensitive to bacitracin: Group A Streptococcus is suseptible to bacitracin. Group B Streptococcus, Group D Streptococcus, and Staphylococci are resistant to bacitracin.
Most common methods for measuring bilirubin are based on the reaction of bilirubin with: Diazotized sulfanilic acid (diazo reagent) reacts with bilirubin to produce colored azodipyrroles, which are measured spectrophotometrically.
The generally accepted age range for homologous blood donation is: 17 - 65 years Prospective donors over 65 may be accepted at the discretion of the blood bank physician. Many donor centers safely involve elderly donors in their collection programs.
The iodine prep is most helpful to identify which of the following parasitic stages: Cysts
Which of the following are not appropriate indications for the use of fresh frozen plasma: Since each unit of fresh frozen plasma (FFP) carries with it the risk of transmitting blood borne pathogens, and other products which do not carry this risk are available, FFP should not be used as a volume expander.
Which of the following will give the best overall picture of a patient's iron stores: The concentration of circulating ferritin is proportional to the size of iron stores
Serum calcitonin is typically elevated in which of the following conditions: Serum calcitonin is normally produced by the C cells of the thyroid. It functions to reduce serum calcium by inhibiting release of calcium from bone. half life of approx 12 minutes. It is characteristically elevated in medullary carcinoma of the thyroid.
Which of the following is found in plasma but absent in serum: Fibrinogen Fibrinogen, is, of course, consumed during the clotting process.
After transfusion, a red cell sample from the donor unit, and the recipient's blood sample, must be kept for at least: Samples utilized for pre-transfustion compatibility testing must be kept for at least 7 days in the laboratory. This is to ensure that there is sample available should any tranfusion reaction occur; as post-tranfusion workups must be performed.
Which of the following is used primarily for the treatment of manic-depression: Lithium is commonly used in the treatment of manic depressive patients. Lithium exerts a dual effect on receptors for the neurotransmitter glutamate; acting to keep the amount of glutamate active between cells at a stable, healthy level, neither too much
Which of the following immunoglobulins is capable of fixing complement by the classical pathway: IgG1, IgG3, and IgM fix complement via the classical pathway. IgA fixes complement through the alternative pathway. Only IgG crossed the placental barrier.
The impedance principle shown in this illustration is best described by the following statement: Blood cells or other particles are counted and sized based on changes in electrical resistance as they pass between two electrodes.
The precursor of the platelet which is commonly only found in the bone marrow is: Platelets are formed by the fragmentation of megakaryocyte cytoplasm.
Which of the following is not associated with RBC macrocytosis? Thalassemia is usually associated with microcytosis. The other conditions like alcoholism, hypothyroidism and vit. B12 deficiency can cause macrocytosis of RBCs.
Rh immune globulin therapy in postpartum women provides: Passive protection Protection against alloimmunization is only for the recent pregnancy. There is of course no long term protection against the development of Rh antibodies if the patient is exposed again in the future.
What is a prominent morphologic feature of lead poisoning: Basophilic stippling is strongly associated with lead poisoning the lead toxicity can affect the bone marrow; causing this phenomenon.
Which of the following options gives in order from most to least important, the factors you would use to select blood for a transfusion: ABO Type Specific Blood, Major Crossmatch Compatibility, Antigen Negative Blood for Patient with antibody reacting only at room temperature
Why would a unit of group O blood never be administered to a Bombay patient: Anti-H in recipient The classic Bombay phenotype (Oh) is characterized by the absence of A, B and H antigens, and the presence of anti-H, which will react from 4o to 37o C. Bombay patients must therefore be transfused pf the Bombay phenotype
Why would a unit of group O blood never be administered to a Bombay patient: Bombay patients must therefore be transfused only with blood from donors of the Bombay phenotype.
Gram positive organisms Gram positive organisms resist decolorization with acetone-alcohol. Gram negative organisms are decolorized, and subsequently stain with safranin.
Detection of a fruity odor in a fresh urine sample may be indicative of which of the following: Conditions such as starvation and diabetes mellitus can lead to an increase of ketones in the urine, giving the urine a "fruity", sweet type of odor.
Each of the following has been shown to induce platelet aggregation except:Epinephrine Serotonin Aspirin Thrombin Aspirin has been shown to inhibit platelet function.
Membrane covering the brain under the skull Meninges
Fluid accumulation due to a malfunction of ability to form and reabsorb fluid Transudate
nflammation of the pleural membranes Pleurisy
Excess accumulation of fluid within any of the body's serous cavities Effusion
The immunogenicity of an antigen is determined not only by certain innate characteristics of an antigen itself but also by the host's genetically immune responsiveness
antigenic determinants: epitopes- also the area where the antigen combines with specific antibody
most anitgenic blood groups A,B RhD antigens
next most antigenic after D antigen K antigen, followed by Fya and common Rh antigens
Approx. 50-75% of D negative individuals would produce anti-D if transfused with only 1 unit of D positive blood
Are well defined chemical groupings that are too small to be immunogenic by themselves but can induce an antibody response when attached to a carrier protein hapten
methods historically used to indirectly calculate the number of antigen sites on RBC membranes radioimmunoassay, enzyme-linked immunosorbent assay, electron microscopy using ferritin-labeled antiimmunoglobulin, and flow cytometry
the combining site of an antibody where it is in physical contact with the antigenic determinant or epitope is called paratope
Blood group antibodies are ussually classified as____, whic reacts with a foreign antigen not present on the patient's own erythrocytes alloantibody
is an antibody which reacts with an antigen on the paitent's on celss autoantibody
is the most common reason for complement activation on the RBC membrane in vivo antibody binding to RBC antigens
complement may also be activated on RBCs via carrier-hapten antibody complex suxh as penicillin-coated RBCs and antipenicillin antibodies
RBC-antibody complexes usually activate complement by what pathway classical pathway
clomplement-fixing IgG antibodies that can induce intravascular hemolysis anti-Kidd antibodies
membrane attact complex C5b6789- this complex polymerizes to form pores in the RBC membrane, so that extracellular fluid enters the cell, causing it to swell and burst by osmotice lysis.
Intravascular RBC hemolysis is usually caused by antibodies directed against what antigens? ABO antigens
type of antibodies that cause the majority of extravascular hemolysis via the RE system, which removes complement-coated RBCs IgG antibodies
C3 convertase C4b2b
factor that inhibits C3 convertase formation and by promoting C3 convertase degradation Decay accelerating factor (DAF)
on RBCs, CR1 (a cofactor) and DAF carry what blood group antigens Knops and Cromer blood group antigens, respectively
C33b/iC3b-coated RBCs are rapidly sequestered in the liver by monocytes and macrophages, which have receptors for C3b
In the absence of complement activation, IgG-coated RBCs are removed by phagocytic cells via Fcy receptors
ABO antigens are a major consideration in solid organ and bone marrow transplantation
ABO epitopes are found on many tissues and body fluids, including RBCs, platelets, and endothelial celss
ABO blood group systems consists of how many antigens and phenotypes? 2 antigens: A and B four phenotypes: A, B, AB, and O
A and B are autosomal codominant antigens
group O phenotype is an autosomal recessive phenoytype, reflecting the absence of a functional ABO gene.
group O individuals express what antigen H antigen, the biosythetic precursor of both A and B antigens
this group is the most frequent ABO phenotype in most populations tested, particularly among native americans group O
Which of the following immunoglobulins is capable of fixing complement by the classical pathway: IgG1, IgG3, and IgM fix complement via the classical pathway. IgA fixes complement through the alternative pathway. Only IgG crossed the placental barrier.
positive surface antigen indicates that the ____ is present which is associated with the acute, late incubation phase. hepatitis B virus
is the first antibody produced after infection with HBV and is used to detect acute infection (convalescent). The IgM antibody to the hepatitis B core antigen...Anti-Hbc IgM
is a test containing both IgM and IgG antibodies to hepatitis B core antigen.Can be used to help detect acute and chronic HBV infections as well as infection recovery The anti-HBc total
is an antibody produced in response to HBV surface antigen; levels in the blood rise during the recovery phase.is also used to detect previous exposure to HBV, such as from vaccination Anti-Hbs
An intact viral particle typically consists of a nucleoprotein core, capsomeres making up the capsid, and a lipid envelope (absent in some viruses). The symmetry of a virus is usually icosahedral, or helical.
The Rh nomenclature which uses the letters DCE is found in which of the following genetic models: Fisher and Race first proposed the existence of the three closely linked genes, and used the DCE terminology to describe their theory.
A simple check which can be employed to verify that hemoglobin and hematocrit values match Hemoglobin X 3 = hematocrit The hematocrit is equal to approximately 3 times the hemoglobin level.
IgM antibodies produced against red blood cells generally: IgM immunoglobulins, in general, tend to react best at room temperature. They are not involved in hypersensitivity reactions, are not identified using the AHG test, and do not react best at 37o C.
What principle(s) of flow cytometry are employed when performing immunophenotyping: Fluorescent antibody tagging and light scatter. Flow cytometry employs a combination of fluorescent antibody tagging of cells and analysis with laser light scatter.
are remnants of nuclear DNA - they may be seen after splenectomy, in hemolytic anemia, and in megaloblastic anemia Howell-Jolly bodies
A delayed hemolytic transfusion reaction is most likely to be the result of which antibodies Jka (Kidd) antibodies are very dangerous; they disappear from circulation quickly and can cause severe delayed transfusion reactions.
the immediate biosynthetic precursor of both A and B antigens. H antigen
H antigen is formed by the addition of what sugar in an alpha1-2 linkage, to a terminal galactose fucose (Fuc)
the product of the H or FUT1 gene, catalyzes the formation of type 2 chain H antigen Fucosyltransferase type 1 (FUT1)
the product of the Secretor gene, catalyses the transfer of fucose to type 1 chain precursors to form type 1 chain H or Le^d antigen Fucosyltransferase type 2 (FUT2)
Inactivating mutations of ___ are responsible for the Bombay and prar-Bombay phenotypes FUT1
The A antigen is formed by A gene glycosyltransferase, which adda an _____ in a alpha 1-3 linkage to the subterminal galactose of H antigen N-acetylgalactosamine (GalNac)
B anitgen is formed by the addition of an ____ to the same galactose by the B gene glycosytransferase alpha1-3 galactose
Biochemically, the A and B antigens are very similar, differing only by the presence of an N-acetyl group
Removal of the N-acetyl group on A antigen by circulating deacetylase enzymes is responsible for the acquired B phenotype
FUT1(H gene) and FUT2(Se gene) are located together on what chromosome position chromosome 19q13.3 and reflect a gene duplication.
The ABO gene locus is located on what chromosome position chromosome 9q34 and encodes the A and B glycosyltransferases
is the Amino acid that is absolutely critical in determining the activity and substrate specificity of the enzyme glycosyltransferase Amino acid 268
Substrate specificity is also influenced by amino acid residues 235 and 266
have been linked to ABO typing discrepancies by an absence of anti-A and/or anti-B in these individuals O03 and a related allele (Aw08)
phenotypes are associated with a single nucleotide deletion (nucleotide 1060) and frameshift,resulting in the loss of a stop codon and synthesis of a longer A enzyme with decreased enzyme activity the A2 and Ael phenotypes
Antibodies against these antigens are the most important antibodies in transfusion medicine. ABO antigens
All reagent cells in the antibody screen are of what group group O cells
ABO antibodies are weak or absent in the sera of newborns until at what age 3-6 months of age and reached in adult levels by 5 - 10 years of age
ABO antibodies are detected as room temperature, saline agglutinins with optimal reactivity at 4C
Most naturally occuring ABO antibodies are of what immunoglobulin isotype IgM isotype
Clinically, ABO antibodies are a cause of HTR and HDFN and are also a cause of rejection in solid organ transplantation
Solid organ transplants should be ABO compatible with the recipient's antisera
is a naturally occuring antibody found in the sera of some A2, A2B, and other weak A subtypes Anti-A1 hemagglutinates A1 RBCs, but not A2 and toher weak A phenotypes, been implicated in transfusion reactions and solid organ rejection, althoug uncommon
is usually a benign, naturally occurring antibody in the sera of A1 and A1B nonsecretors Anit-H, reacts most strongly with group O, followed by A2, B, A2B, A1 and A1B
Because H antigen is present to some degree on all RBCs, anti-H is an autoantibody in most individuals
Malaria has been shown to bind what group antigens A and B antigens with rosette formation, a possible risk factor in cerebral malaria
was the second blood group system identified after ABO MNSs blood group, antigens are expressed only on RBCs same as with Rh antigens
Three major null phenotypes are present in the MNSs system, they are U-, M^k, En (a-). The U- phenotype is the most common and is observed EXCLUSIVELY on blacks
In S-s-U- individuals, complete loss or a recombination of glycophorin B occurs, leading to altere expression of S/s and U antigens
Recombinant glycophorin B, such as the Henshaw phenotype, can react weakly with some exammples of human anti-U and are known as U variants (S-s-U^var)
this phenotype is the result of recombination between glycophorin A and B genes to form a Lepore-type A-B hybrid (exons A!-B2-B5) lacking most of glycophorin A (GYPA) En(a-) phenotype
this phenotype lacks all MNSs antigens, inculding En(a), as the result of recombination and deletion of glycophorins A and B (GYPA and GYPB). The M^kM^k phenotype
the M/N antigens reside on Glypcophorin A GYPA (CD235A), a major RBC membrane glycoprotein.
is the major sialomucin on RBCs and contributes significantly to the overall negative charge or zeta potential GYPA (Glycophorin A)
The S/s and U antigens reside on Glycophorin B (GYPB), a related RBC glycoprotien
The genes for GYPA and GYPB reside on what chromosome position chromosome 4q28-q31
Anti-M and Anti-N are naturally occurring antibodies of what type IgM isotype, usually detected as room temperature saline agglutinins
Because the M and N antigens reside on GYPA, the reactivity of anti-M and anti-N antigens is destroyed by pretreatment of RBCs with proteolytic enzymes or neuraminidase
Anti-M and Anti-N can be enhanced by acidification of serum to pH 6.5, use of albumin diluent, or preincubation of RBCs in a glucose-containin solution
Anti-M is a commonly encountered antibody in the blood bank. In contrast, anit-N is distinctly uncommon, despite the fact that 25% of patients are negative for N antigens
The rarity of anti-N is due to the presence of 'N'antigen on GYPB. When observed, anti-N is usually an autoantibody, reacting with both N and 'N'antigens
In general, anti-M and anti-N are clinically insignificant antibodies and on rarely cause HTR or HDFN. Unlike anti -M and anti-N, antibodies to S,s and U antigens are always clinically significant
Ani-S, anti-s and anti-U are all IgG isotype, reactive at 37c, arising from immune stimulation
are rich in O-glycans and sialic acid, they contribute significantly to the zeta potential of red cells, decreasing homotypic and heterotypic red cell adhesion they are GYPA and GYPB
GYPA also facilitates transport and expression of Band 3 (AE1/Diego), a critical protein in gas exchange
Increased Band 3 expression and osmotic resistance can be observed with Miltenberger type III red cells, a GYP-A-B hybrid
GYPA and GYPB may play a role in what infections Plasmodium falciparum infections. these parasite can adhere to RBCs via silaic acid, which is highly expressed on glycophorins
an example of glypophorin-deficient phenotype which are resistant to P. falciparum in vitro En(a-)
P blood group system historically consists of one antigen (P1, ISBT 003) and two members of the GOB collection, P^k and P (ISBT 028)
P blood group antigens are similar to Lewis system, consisting of an antigenically active carbohydrate moiety covalently linked to a ceramide lipid tail
P^k and P antigens are high freequency antigens on most donor RBCs >99%
RBCs are particularly rich in P antigen which makes up nearly 6% of the rotal RBC lipid.
P^k and P antigens are also expressed on nonerythroid cells, including.. lymphocytes, platelets, plasma, kidney, lung, heart, endothelium, plasma, uroepithelium, fibroblasts, and synovium
In contrast, P1 antigen is uniquely expressed on RBCs. Approx. 79% of Caucasian and 94% of black donors express P1 on their RBCs.
Because they lack P antigen, p and P^k individuals are resistant to what virus Parvovirus B19
Most commonly observed antibody of the P blood group antibodies Anti-P(1), which is naturally occuring antibody of IgM isotype and is often detected as weak, room temperature agglutinin
Anti-P(1) can bind complement and may be detected in the indirect agtigloblulin test if polyspecific antihuman globulin (AHG) is used
Anti-P1 titers are often elevated in patients with hydatid cyst disease or fascioliasis (liver fluke) , and in bird fanciers
Anti-P(1) in general is not clinically significant and its presence rarely requires transfusion of antigen-negative blood and is not a cause of HDFN
Wiener Nomenclatures for antigens of the Rh Blood group system Rho, rh', rh", hr', hr"
Fisher-Race D C E c e
Rosenfield RH1, RH2, RH3, RH4, RH5
RO is Dce, high frequency in Blacks
R1 is DCe, high frequency in Caucasians
R2 is DcE
Rz is DCE
r is ce
r'is Ce
r" is cE
ry is CE
historically known as anti-Tjâ is a separable mixture of anti-P, antiP1, anti-P^k in the sera of the individuals Anti-PP1P^k, are naturally occuring and may be IgM only or IgM plus IgG(IgG3), and are potent antibodies
In women, alloanti-PP1P^k and allonanti-P are associated with HDFN and spontaneous abortion
is also a naturally occuring IgM alloantibody in the serum of P^k (and p) individuals Alloanti-P, and is a potent hemolysis and can cause in vivo hemolysis following transufusion of P positive [P(1) and P(2)] RBCs
Alloanti-P is a cause of HDFN and is associated with spontaneous abortion
An autoantibody seen in patients with paroxysmal cold hemoglobinuria (PCH), a clinical syndrome that may occur in children followin viral infection Aunto-Anti-P (Donath-Landsteiner), an IgG, biphasic hemolysin capable of binding RBCs at colder temperature, followed by intravascular hemolysis at body temperature.
this antigen is a marker of apoptosis in germinal center B cells, Burkitt lymphoma, and lymphoblastic leukemia P^k antigen
is a marker of embryonic and mesenchymal stem cells and is implicated in adhesion, cell signaling, and metastasis in renal cell and breast carcinoma Luke (LKE) antigen
this antigen is the receptor for parvovirus B19, a single stranded DNA virus associated with multiple clinical sequelae, including aplastic crises. P blood group antigen
this antigen can bind human immunodefieciency virus (HIV) and may confer resistance to HIV infection P^k antigen, also serves as a receptor for Streptococcus suis and Pseudomonas aeruginosa
these antigens are receptors for shiga toxins, produced by shigella dysenteriae and enterohemorrhagic Escherichia coli (EHEC) strains P1 and P^k antigens
these blood group antigens on uroepithelium are cell receptors for P-fimbriae, a bacterial adhesin and colonixation factor expressed on uropathogenic E. coli strains P, P^k, and LKE blood group antigens
This investigator proposed a single locus inheritance system with eight alternative common alleles coding for two Rh agglutinogens, capable of expressing up to 3 different antigenic determinants Weiner
These investigators proposed a system of three closely linked loci or subloci on each chromosome, which were inherited as a block of genes (haplotype) Fisher and Race, they also annoucned the DCE nomenclature to name the alleles, including the use of "d" to deignate the lack of D locus
This investigator proposed a numeric system of naming the antigens in 1962, because the increasing number of Rh antigens rendered an alphabetic notation impractical Rosenfeld
It is now clear that Rh complex consist of three integral membrane proteins, they are RhD, RhCE, and Rh-associated glycoprotein (RhAg) and these are all erythroid-specific proteins
this may help maintain the phospholipid asymmetry of the RBC membrane Palmitoylation of the Rh proteins
is the most antigenic of all the Rh antigens, resides on the RHD protein D antigen
historically known as Dû, characterized by weak or absent RBC agglutination by anti-D during routine serologic testing Weak D
are RHD proteins with missing D epitopes Partial D antigens. Although type as D- postive , persons with partial D antigens can make alloanti-D antibodies reactive with allogeneic, but not autologous, RBCs
Rh ngative (D-) occurs in approximately what percentage in white donors 15%, almost always in association with a ce/ce or rr phenotype.
is a high frequency antigen present on virtually all D-positive and C-positive RBCs G antigen (RH12), has been identified as Ser103, a C-type antigen, on RHD and RHCE protiens
lack all Rh antigens as a result of an apparent absence of RhD and RhCE proteins Rh(null) erythrocytes. lack the high frequency antigens Fy5 and LW and may have markedly decreased expression of S/s and U antigens
have markedly decreased Rh and RhAg expression, detectable only by careful adsorption and elution studies Rh(mod) RBCs
is the most immunogenic Rh agntigen, followed by c, E, C and e D antigen
antibodies against Rh antigens are the result of immune stimulation by transfusion or pregnancy
antiC^w and anti-E can be naturally occuring
Most antibodies against Rh antigens are of what isotype IgG, although rare examples of IgM and IgA are known
Anti-Rh antibodies are reactive at what temp 37C and are usually detected in the AHG phase of testing. The reactivity of anti-Rh can be enhanced with enzyme-treated RBCs
this method is extremely sensitive for the detection of Rh antibodies gel method
Rh antibodies do not fix complement. Imcompatible RBCs are almost always cleared through extravascular destruction
R1R1(DCe/DCe) patients are at increased risk of delayed hemolytic transfusion reactions because of subsequent development of anti-c, many blood bankers advocate transfusion only R1R1 units to R1R1 patients.
Antibodies against Rh antigens are also a major cause of HDFN. All Rh-negative women should receive Rh immune globulin (IgG anti-D) prophylactically in midpregnancy, following an invasive procedure (i.e.,amniocentesis), and immediately after delivery to prevent alloimmunization
Rh immune globulin prophylaxis is also recommended in women with partial d phenotypes because these women can be at risk for D alloimmunization
Rh immune globulin may also be given following transfusion of RhD+ platelet concentrates or after accidental transfusion of RhD+ RBCs
Administration of one vial of Rh immune globulin is recommended for every 30 mL whole blood or 15 mL packed RBCs transfused
Rh immune globulin should be given within how many hours of exposure within 72 hours of exposure to prevent active immunization
Rh immune globulin is not given to Rh negative women who are already immunized to D antigen (i.e., have anti-D)
It is also recommended to give Rh immunemglobulin to Rh-negative women with anti-G alloantibodies.As stated earlier,anti-G behaves as an anti-C + anti-D because of recognition of a Ser103 or C-type antigen on both RhD and RhCE proteins
One clue suggesting the presence of anti-G is an anti-C titer at least fourfold higher than anti-D
Lutheran appears on red cells at what stage of hemopoiesis at the orthochromatic erythroblast stage, concurrent with binding of red cells to laminin
Lutheran antigens are ubiquitously expressed on human tissues including colon, small intestine, ovary, testis, prostate, thymus, spleen, pancreas, kidney, skeletal muscle,liver,lung, placenta, brain, heart, and bone marrow
Lutheran antibodies are not clinically significant and are only rarely associated with HDFN and HTR
is the most common Lutheran alloantibody encountered in the blood bank and is often an IgM, room temp agglutinin Anti-Lu^a
Antibodies against Lu^b and other Lutheran antigens are most often of what isotype IgG isotype, reacting best in the IAT
Reactivity of anit-Lu^a, Lu^b, and other Lutheran antibodies can be inhibited by pretreatment of RBCs with chymotrypsin, trypsin, 2-aminoethylisothiouronium bromide (AET), and dithithreitol (DTT)
Biologically, Lutheran is a high-affinity receptor for laminin, a basement membrane protein involved in cell differentiation, adhesion, migration, and proliferation
In sickle cells, increased expression of this antigen on reticulocytes and sickle celss may contribute to the pathophysiology of vaso-occlusive crises Lutheran
Kell antigen is found on RBCs, erythroid and megakaryocyte progenitors, skeletal muscle, and testis
is an autosomal recessive, null phenotype that completely lacks all Kell antigens KoKo, these individuals can make an alloantibody to the Kell glycoprotein (anti-Ku)
KoKo red cells can be produced in the laboratory by treating Kell-positive RBCs with sulfhydryl-reducing agents
Kell antigens are significantly depressed/absent on McLeod RBCs, an X-linked recessive phenotype characterized by the absence of XK protein on RBCs, acanthocytes, and neuromuscular disorders
McLeod individuals are incompatible with both Kell-positive and KoKo RBCs
The McLeod phenotype can also be associated with chronic granulomatous disease (CGD), a functional neutrophil defect resulting in severe, recurrent, life-threatening bacterial infections
The Lewis blood group system is unusual in that the Lewis antigens are NOT of erythroid origin. Primarily consists of two antigens: Lewis^a (Le^a) and Lewis^b (Le^b)
On RBCs, the Lewis antigens reside on glycosphingolipids
Lewis antigens are synthesized in the gastrointestinal tract and passively adsorbed onto RBCs from a soluble pool of secreted Lewis substance in plasma.
Tissues and fluids expressing Lewis include plasma, saliva, RBCs, platelets, lymphocytes, endothelium, uroepithelium, and bowel mucosa
Three Lewis phenotypes are observed in adults Le(a+b-), Le(a-b+), Le(a-b-). The Le(a+b+) is only rarely observed, usually on RBCs of very young children and some individuals of Polynesian, Janpanese, or Taiwanese ancestry
Le(a-b-) phenotype is 5 times more common in blacks than in Caucasians. also increased in neonates owing to the developmentally delayed expression of the Lewis and Secretor genes
Because Lea and Leb are glycosphingolipids, antibody reactivity can be enhanced by pretreatment of RBCs with enzymes
Anti-Leb can be observed in individuals of Le (a+b-) or Le (a-b-)phenotype, whereas anti-Lea is observed only in Le (a-b-) individuals
Anti-Lea is not observed in the Le (a−b+)phenotype because these individuals synthesize a small amount of Le^a
Lewis antibodies are not associated with HDFN and are only rarely associated with hemolytic transfusion reactions
For transfusion, patients with anti-Lewis antibodies reactive only at room temperature may be safely transfused with crossmatch–compatible RBCs. In contrast, rare examples of anti-Lea or anti-Leb that are hemolytic in vitro should receive antigen-negative, crossmatch–compatible RBC
The Lewis blood group antigens play an important role in disease. Helicobacter pylori, a causative agent of gastritis and ulcers, binds H, Leb, and Ley antigens via BabA recognition of a terminal Fucá1–2Gal epitope
A Lewis null and/or nonsecretor phenotype has also been linked with a higher incidence of recurrent Candida vaginitis and urinary tract infection
A Le (a−b−) phenotype is associated with an increased incidence of heart disease. Conversely,a nonsecretor phenotype protects against Norovirus infection, a highly contagious RNA virus responsible for 23 million gastrointestinal infections a year
Sialyl-Lea is also the epitope for the tumor marker CA 19-9, a useful serologic marker for monitoring patients with gastrointestinal and other malignancies.
Duffy (FY) blood group system contains five antigens: Fy^a, Fy^b, Fy3, Fy5, and Fy6
Fya and Fyb are autosomal codominant antigens, whereas Fy3, Fy5, and Fy6 are high incidence antigens present on all RBCs except the Duffy null phenotype
Fya and Fyb antigens are common in Caucasians, whereas the Duffy null or Fy (a−b−) phenotype is the predominant phenotype in blacks
In addition to RBCs, the Duffy antigens are expressed on cerebellar Purkinje cells and postcapillary venule endothelial cells
The Duffy antigens reside on DARC or Duffy antigen receptor for chemokines
The Fya, Fyb, and Fy6 antigens reside on the amino-terminal domain of DARC and are sensitive to proteolytic cleavage. The amino-terminal domain is also the binding site for P. vivax and plays a role in chemokine binding
Antibodies against Fya, Fyb, and other Duffy antigens are clinically significant.They are associated with HDFN and both immediate and delayed hemolytic transfusion reactions. They are usually of IgG isotype, reactive at 37° C, and are detected only in the IAT
Antibodies against Fya, Fyb,and Fy6 antigens, which reside on the long amino-terminal domain of DARC, can be inhibited by prior protease digestion of RBCs
Fy5 and Fy3 antigens are relatively resistant to protease digestion
Anti- Fy6 has not been observed clinically but is the epitope for an anti-Duffy monoclonal antibody that blocks P. vivax binding
DARC is also the receptor for P. vivax, which binds DARC at the Fy6 epitope. Fynull individuals are resistant to most P. vivax strains, providing a selective advantage to populations living in malaria endemic areas
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