Hemolytic Disease of the Fetus and Newborn (HDFN), AIHA, and HLA Testing

Comprehensive practice flashcards covering Hemolytic Disease of the Fetus and Newborn (HDFN), Autoimmune Hemolytic Anemia (AIHA), HLA typing, and the use of blood group systems in medico-legal and paternity cases.

What is the definition of Hemolytic disease of the fetus and newborn (HDFN)?

A blood disorder that causes a baby’s red blood cells to break down quickly.

What is the term for the breakdown of red blood cells?

Hemolysis

What two conditions are caused by hemolysis in the first few days to weeks of a baby’s life?

Anemia (low number of red blood cells) and jaundice (increased bilirubin level).

What are two potential complications of untreated severe jaundice in HDFN?

Hearing problems/deafness and brain damage.

What biological situation triggers HDFN?

A mismatch between the mother’s and baby’s blood type and/or Rh factor during pregnancy.

What are five common symptoms associated with HDFN?

Pale skin, yellowing of skin or eyes (jaundice), very dark urine, increased fatigue or irritability, and rapid heart rate.

Which type of incompatibility generally requires more monitoring and treatment: Rh or ABO?

Rh incompatibility

When can a mother’s blood mix with the baby’s blood to cause a mismatch?

At birth, when the placenta breaks away, during a miscarriage, or during a prenatal test.

Why does HDFN typically not occur with the mother’s first pregnancy?

The baby is usually born before the mother has developed many of the antibodies against the baby's red blood cells.

What is the purpose of an Anatomy Ultrasound in diagnosing HDFN?

It is a high-resolution ultrasound used to assess for enlarged organs, which can indicate a fetus is anemic.

What is Amniocentesis?

A medical procedure where a small amount of amniotic fluid is extracted to screen for genetic abnormalities.

How does an Intrauterine blood transfusion help a fetus with HDFN?

It gives the baby new red blood cells to prevent severe anemia via a needle guided into the umbilical cord vein.

What is the role of a neonatologist in HDFN care?

They specialize in treating newborns and assess factors like breathing, heart rate, and other newborn health problems.

What does a Direct antiglobulin test (DAT) check for in a newborn?

It checks to see if there are antibodies against red blood cells.

What iron-rich protein is measured in a Complete blood count (CBC) to look for anemia?

Hemoglobin

What does a high Reticulocyte count indicates when hemoglobin is low?

The baby is making more new red blood cells.

What yellow substance is produced when red blood cells break down and must be processed by the liver?

Bilirubin

What treatment involves placing a baby under special lights to help remove extra bilirubin?

Phototherapy

What is the function of Intravenous immunoglobulin (IVIG) in HDFN treatment?

It contains antibodies from donors that help keep the baby from destroying their own red blood cells and lower bilirubin levels.

What is an Exchange transfusion?

A procedure that removes blood with high bilirubin and replaces it with blood that has normal bilirubin levels.

What complication can occur because the heart is not getting enough oxygen-rich hemoglobin due to severe anemia?

Heart failure

How long do the antibodies that destroy the baby's red blood cells usually last in the baby's life?

$8$ to $12$ weeks of life.

What is Autoimmune hemolytic anemia (AIHA)?

A rare form of anemia occurring when the immune system accidentally destroys the body's own red blood cells.

What is the difference between primary and secondary AIHA?

Primary AIHA has no known cause; secondary AIHA is caused by another issue like a virus or blood cancer.

Warm AIHA involves which type of immunoglobulin antibodies?

Immunoglobulin G ($IgG$)

At what temperature do Warm AIHA antibodies target red blood cells?

At or above $98.6\,^{\circ}F$ ($37\,^{\circ}C$).

Cold AIHA involves which type of immunoglobulin antibodies?

Immunoglobulin M ($IgM$)

What is another name for Cold AIHA used by healthcare providers?

Cold agglutin disease (CAD)

What are three symptoms specific to Cold AIHA that are not shared with Warm AIHA?

Chest pain, cold hands and feet, and pain in the back of the legs.

Which autoimmune diseases are linked to secondary AIHA?

Lupus, Hashimoto’s disease, and rheumatoid arthritis.

Which cancers are associated with secondary AIHA?

Chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma.

Name four types of blood tests used to diagnose AIHA.

Coombs test, LDH, Peripheral blood smear, and Reticulocyte count.

What medications are commonly used to treat Warm AIHA?

Immunosuppressants and corticosteroids.

What is a common treatment for Cold AIHA besides staying warm?

Rituximab

Why might a doctor perform surgery to remove the spleen in a patient with AIHA?

The spleen is often where antibodies destroy red blood cells; removing it can protect the remaining cells.

What does HLA stand for?

Human Leukocyte Antigen

What is the primary function of HLA molecules?

To differentiate between the body’s own cells (“self”) and foreign invaders (“non-self”).

Why is HLA matching vital in organ transplantation?

To minimize the risk of the recipient’s immune system rejecting the transplanted organ.

In which medical process is determining an individual’s specific HLA antigens or alleles performed?

HLA typing

Which older method of HLA typing utilizes known antibodies reacting with specific antigens?

Serological Typing

What does PCR stand for in the context of molecular HLA typing?

Polymerase Chain Reaction

What technique provides a highly accurate identification of HLA alleles by determining the DNA sequence?

Next-Generation Sequencing (NGS)

What is paternity testing, in the context of parentage testing?

A genetic analysis used to establish a biological relationship between a father and a child.

Name three legal reasons why parentage testing is important.

Child custody, child support, and inheritance rights.

What role does HLA typing play in medical diagnostics for Type 1 Diabetes and Rheumatoid Arthritis?

Certain HLA types are associated with an increased risk for these diseases, aiding in risk assessment.

What are the two primary roles of blood group systems in medico-legal investigations?

Individual identification and establishing biological relationships.

What antigens and antibodies an individual with Type B blood has?

B antigens on red blood cells and anti-A antibodies in plasma.

What antigens and antibodies an individual with Type O blood has?

Neither A nor B antigens on red blood cells and both anti-A and anti-B antibodies in plasma.

Which blood type has both A and B antigens but no anti-A or anti-B antibodies?

Type AB

The Rh system is characterized by the presence or absence of which antigen?

D antigen

What are the possible genotypes for an Rh-positive individual?

$DD$ or $Dd$

What is the genotype for an Rh-negative individual?

$$dd$$

If a child is Rh-positive but both parents are Rh-negative, is this genetically possible?

No

How should dry bloodstains be collected at a crime scene?

They can be scraped or swabbed with sterile water.

Which technique is used for dried bloodstains where cell lysis has occurred?

Absorption-Elution Techniques

What is the genetic principle behind paternity exclusion?

A child inherits one set of alleles from each parent; if a child has an antigen neither parent possesses, the alleged parent is excluded.

A child is Type A (genotype $I^A I^A$ or $I^A i$) and the mother is Type O (genotype $ii$). What allele must the child have inherited from the father?

$$I^A$$

Can an alleged father with Type B blood (genotype $I^B I^B$ or $I^B i$) be the biological father of a Type A child born to a Type O mother?

No, because the father cannot provide the necessary $I^A$ allele.

If a child is Rh+ ($DD$ or $Dd$) and the mother is Rh- ($dd$), why is an Rh- alleged father excluded?

The child must have inherited a $D$ allele, which an Rh- father ($dd$) cannot provide.

What is required to identify a disaster victim via blood typing if visual identification is not possible?

Anti-mortem blood type records or comparison with family members' blood types.

What is the 'chain of custody' in forensic evidence?

A strict, unbroken record of who handled the evidence from collection to court presentation.

What is the ethical requirement for non-forensic testing, such as private paternity tests?

Informed consent

In HDFN, what is the significance of the umbilical cord vein?

It is the site where a needle is guided to give an intrauterine blood transfusion directly to the baby.

Why is early delivery sometimes necessary for babies with HDFN?

To prevent the condition from worsening once the baby is big enough.

What is the goal of discharge planning for a baby with HDFN who requires blood transfusions?

The hematology team at Nationwide Children's will assess labs once or twice a week to decide if further transfusions are needed.

What kind of specialist should be chosen for a baby’s routine checkups and immunizations after HDFN treatment?

A local pediatrician

Which virus examples are linked to secondary AIHA?

Cytomegalovirus, Epstein-Barr virus, hepatitis, and HIV.

In AIHA, what measurement does a bilirubin test provide?

It measures how much bilirubin is in the blood from red blood cell breakdown.

Which HLA typing method analyzes DNA using NEXT-Generation Sequencing (NGS)?

Molecular Typing

Why is the ABO system useful for narrowing down suspect pools in forensic investigations?

Because of its distinct antigen profiles and predictable inheritance patterns.