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Questions and Answers
What significantly enhances the reactivity of Rh antibodies?
What significantly enhances the reactivity of Rh antibodies?
- Incubation with untreated red blood cells
- Incubation with enzyme-treated red blood cells (correct)
- Presence of complement proteins
- Exposure to heat-treated plasma
Which type of antibodies are formed after exposure to red blood cells?
Which type of antibodies are formed after exposure to red blood cells?
- Immunoglobulin M antibodies
- Complement antibodies
- Autoantibodies
- Alloantibodies (correct)
What is the most immunogenic Rh antigen?
What is the most immunogenic Rh antigen?
- Rh(E)
- Rh(C)
- Rh(c)
- Rh(D) (correct)
How long do Rh antibodies typically remain in circulation once formed?
How long do Rh antibodies typically remain in circulation once formed?
What is a common characteristic of individuals who develop one Rh antibody?
What is a common characteristic of individuals who develop one Rh antibody?
Why should Rh(D)-negative recipients receive red blood cells lacking the D antigen?
Why should Rh(D)-negative recipients receive red blood cells lacking the D antigen?
What is the most common phenotype with the highest number of D antigen sites?
What is the most common phenotype with the highest number of D antigen sites?
What condition can result from a CE deletion in Rh(D)-positive individuals?
What condition can result from a CE deletion in Rh(D)-positive individuals?
In what situation might a person's cells appear Rh(D) negative with some anti-D reagents?
In what situation might a person's cells appear Rh(D) negative with some anti-D reagents?
What is the relationship of the RHC gene to the RHD gene concerning D antigen expression?
What is the relationship of the RHC gene to the RHD gene concerning D antigen expression?
What results from the weakened D condition also known as Du?
What results from the weakened D condition also known as Du?
Which phenotype demonstrates a partial deletion leading to the most D antigen sites?
Which phenotype demonstrates a partial deletion leading to the most D antigen sites?
Where is weak D more commonly found?
Where is weak D more commonly found?
What is the main characteristic of weak D?
What is the main characteristic of weak D?
How do most partial D individuals react to Rh(D) typing?
How do most partial D individuals react to Rh(D) typing?
What testing method is involved in confirming weak D?
What testing method is involved in confirming weak D?
What is a potential consequence for Rh(D)-negative recipients of weak D or partial D blood?
What is a potential consequence for Rh(D)-negative recipients of weak D or partial D blood?
Why is the weak D test not routinely performed on patients?
Why is the weak D test not routinely performed on patients?
What characteristic is associated with most common partial D phenotype in individuals of European ethnicity?
What characteristic is associated with most common partial D phenotype in individuals of European ethnicity?
What precautions should be taken when transfusing patients with suspected weak or partial D?
What precautions should be taken when transfusing patients with suspected weak or partial D?
Why is antisera used in routine patient typing limited in specificity?
Why is antisera used in routine patient typing limited in specificity?
Which antigen is considered the most immunogenic among the Rh antigens?
Which antigen is considered the most immunogenic among the Rh antigens?
What determines the presence of the f antigen on a red blood cell?
What determines the presence of the f antigen on a red blood cell?
Which statement about the Cw antigen is true?
Which statement about the Cw antigen is true?
What is the primary immunoglobulin class of most Rh antibodies?
What is the primary immunoglobulin class of most Rh antibodies?
At which temperature can Rh antibodies typically be detected after incubation?
At which temperature can Rh antibodies typically be detected after incubation?
Which antigen is antithetical to the high-incidence antigen MAR?
Which antigen is antithetical to the high-incidence antigen MAR?
What is the immunogenicity order of common Rh antigens from most to least?
What is the immunogenicity order of common Rh antigens from most to least?
Which antigen is often found on red blood cells expressing the D or C antigen?
Which antigen is often found on red blood cells expressing the D or C antigen?
What is the primary purpose of weak D testing in Rh(D)-negative neonates?
What is the primary purpose of weak D testing in Rh(D)-negative neonates?
What is a hybridoma in the context of clonal antisera?
What is a hybridoma in the context of clonal antisera?
Which of the following is true about high-protein anti-D reagents?
Which of the following is true about high-protein anti-D reagents?
What differentiates low-protein antisera from high-protein antisera?
What differentiates low-protein antisera from high-protein antisera?
What is a major advantage of using clonal reagent anti-D over the historical human source antisera?
What is a major advantage of using clonal reagent anti-D over the historical human source antisera?
Why was a parallel control important when using high-protein anti-D reagents?
Why was a parallel control important when using high-protein anti-D reagents?
Which type of antisera utilizes IgG anti-D that has been chemically modified?
Which type of antisera utilizes IgG anti-D that has been chemically modified?
What characteristic of modern monoclonal blend reagents influences the requirement for a parallel control?
What characteristic of modern monoclonal blend reagents influences the requirement for a parallel control?
Study Notes
The D Antigen
- The D antigen is the strongest immunogenic antigen in the Rh system.
- Rh(D)-negative recipients should only receive Rh(D)-negative blood products.
- The D antigen does not express dosage, but Rh(D)-positive individuals express varying numbers of D antigen sites.
- R2R2 phenotype (most common) has 16,000 – 33,000 D antigen sites per red blood cell.
- D– – (rare) has 100,000–200,000 D antigen sites per red blood cell.
Weakened Expression of D
- Some individuals express weak D antigens, which are undetectable by some anti-D reagents.
- C antigen in the trans position to D can suppress D antigen expression.
- Weak D is a quantitative deficiency in D antigen expression.
- Partial D is a qualitative alteration of the D antigen.
- Weak D testing is performed on blood donors to label units correctly and on neonates born to Rh(D)-negative mothers to determine alloimmunization risk.
- Weak D testing can also resolve discrepancies in Rh typing.
Rh Antisera
- Clonal antisera has replaced human source antisera in most cases.
- Clonal antisera is usually a blend of monoclonal antibodies to detect more than one epitope of the D antigen.
- Anti-D reagents can be IgG, IgM, or a combination.
Other Cell Antigens
- The C, c, E, and e antigens are codominant and express dosage.
- The C/c antigens differ at position 103, and the E/e antigens differ at position 226.
- The G antigen is found on red blood cells that express D or C antigens.
- The Cw antigen is found in about 2% of people of European ethnicity.
- The f (ce) antigen is expressed when both c and e antigens are present on the red blood cell and the respective genes are in the cis position.
- The Ce antigen is expressed when C and e are found in the cis position.
Rh Antibodies
- Most Rh antibodies are IgG and react during the antiglobulin phase of testing.
- Rh antibodies are red blood cell stimulated.
- The Rh(D) antigen is the most immunogenic.
- Rh antibodies remain in circulation for long periods.
- Rh antibodies do not bind complement but cause extravascular hemolysis.
- Individuals who develop one Rh antibody are more likely to develop others.
- Some autoantibodies have apparent Rh specificity.
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Description
This quiz explores the D antigen and its significance within the Rh blood group system. It covers aspects such as immunogenicity, weak D expressions, and testing protocols for determining Rh typing. Test your knowledge on these essential concepts in transfusion medicine.
