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Which of the following cells express HLA Class I molecules?

a) Only antigen-presenting cells
b) All nucleated cells and platelets
c) B lymphocytes and monocytes only
d) Red blood cells

b

HLA Class II proteins are primarily found on:

a) All cells
b) Cytotoxic T cells
c) Platelets
d) B lymphocytes, monocytes, dendritic cells

d

Which HLA antibody detection method uses fluorescent-labeled nucleotides and provides high-resolution typing?

a) Complement-dependent cytotoxicity (CDC)
b) Sequence-specific primers (SSP)
c) Sequence-based typing (SBT)
d) Panel reactive antibody (PRA)

c

What is the purpose of a virtual crossmatch in transplantation?

a) Physically mix recipient serum with donor cells
b) Predict compatibility based on HLA typing and antibody profile
c) Determine ABO compatibility only
d) Test for Rh antibody

b

Which HLA class is primarily responsible for immune platelet refractoriness?

a) Class I
b) Class II
c) Class III
d) ABO incompatibility

a

What is the clinical significance of detecting HLA antibodies before a transfusion or transplant?

a) Prevents anemia
b) Prevents hemophilia
c) Reduces graft rejection and platelet refractoriness
d) Prevents ABO mismatch

c

In which of the following reactions is HLA thought to play a key role?

a) Hemolytic transfusion reaction
b) TRALI and FNHTR
c) Iron overload
d) Anaphylaxis

b [HLA antibodies (especially against leukocytes) are linked to these conditions.]

A highly sensitized transplant recipient has a PRA of 80%. What does this indicate?

a) They are unlikely to reject any graft
b) 80% of donors will be incompatible
c) They only react to Class II antigens
d) They have low allosensitization

b [PRA reflects how likely a patient is to be incompatible with random donors.]

Which of the following tests can distinguish between IgG and IgM HLA antibodies?

a) CDC assay
b) Flow cytometry
c) Sequence-specific oligonucleotide test
d) Panel reactive antibody (PRA) test

b [Flow cytometry can detect antibody isotypes and even non-complement-fixing antibodies.]

What does the Panel Reactive Antibody (PRA) test measure?

a) ABO compatibility
b) Degree of antigen presentation
c) % of donor HLA types that react with patient antibodies
d) Strength of Rh antigen

c [Higher PRA = greater sensitization to HLA = harder to match.]

In hematopoietic stem cell transplantation, high-resolution HLA matching is done at which loci?

a) A, B, D
b) A, B, DR
c) A, B, C, DRB1, DQB1
d) A, DQ, DP

c [These are critical loci for HSCT matching to avoid rejection and GVHD.]

Which of the following is NOT a method for HLA genotyping?

a) SSO
b) SSP
c) CDC
d) SBT

c [CDC (complement-dependent cytotoxicity) is an antibody detection method, not genotyping.]

HLA typing is most helpful in diagnosing which of the following post-transfusion complications?

a) Hemolysis
b) Iron overload
c) Platelet refractoriness
d) Urticaria

c [Patients may not respond to platelet transfusion due to anti-HLA antibodies.]

In TRALI, which HLA-related mechanism is most commonly involved?

a) Anti-RBC antibody formation
b) IgA deficiency
c) Donor anti-HLA antibodies reacting with recipient leukocytes
d) Complement-mediated hemolysis

c [These cause pulmonary capillary damage and neutrophil aggregation.]

What term describes the phenomenon where HLA genes are inherited together more often than expected by chance?

a) Haplotype skipping
b) Crossmatching
c) Linkage disequilibrium
d) Autoimmunity

c [It explains why some HLA gene combinations are passed on as a set.]

A 35-year-old leukemia patient has received multiple random donor platelet transfusions, but her post-transfusion platelet counts remain low. She has no signs of active bleeding, sepsis, or splenomegaly.

Q1: What is the most likely explanation?
a) ABO incompatibility
b) HLA alloimmunization
c) Hemolytic transfusion reaction
d) Platelet contamination

b [Patients who receive repeated platelet transfusions may develop anti-HLA antibodies, which destroy transfused platelets.]

A 60-year-old male is being evaluated for a kidney transplant. His PRA is 85%, and a virtual crossmatch was performed.

Q2: What does this PRA value indicate?
a) He has a low risk of graft rejection
b) Most donors will be compatible
c) He is highly sensitized and hard to match
d) He has a perfect HLA match

c [A PRA of 85% means 85% of potential donor HLA types are incompatible.]

A patient develops acute respiratory distress 20 minutes after receiving a unit of plasma. Vitals show low blood pressure and hypoxia. No fever or allergic symptoms are present.

Q3: What is the most likely cause?
a) Anaphylaxis
b) TACO
c) TRALI
d) FNHTR

c [TRALI is caused by donor anti-HLA or anti-neutrophil antibodies reacting with recipient leukocytes, leading to pulmonary edema.]

A patient requires a bone marrow transplant. The donor match is assessed at the allele level using high-resolution typing.

Q4: Which HLA loci must be matched at high resolution for HSCT?
a) A, B, C only
b) A, B, C, DRB1, DQB1
c) A, DQ, DP
d) A and B only

b

A transplant candidate undergoes antibody screening. The lab uses flow cytometry to detect non-complement-fixing antibodies.

Q5: Which antibody class can flow cytometry distinguish?
a) IgG vs IgA
b) IgG vs IgM
c) IgE vs IgM
d) IgM vs complement

b [Flow cytometry can differentiate antibody classes and detect antibodies that do not activate complement.]

Which of the following viruses is NOT typically tested for in donor blood because the risk of transfusion is extremely low?

a) HIV
b) HBV
c) HAV
d) HCV

c [HAV is transmitted via the fecal-oral route and rarely through transfusion.]

What is the most common bacterial transfusion risk?

a) Contaminated RBCs
b) Contaminated cryoprecipitate
c) Bacterial contamination of platelets
d) Bacterial contamination of FFP

c [Platelets are stored at room temperature, which encourages bacterial growth.]

What is the purpose of a lookback procedure?

a) To find out which donors received infected blood
b) To track what patients received blood from an infected donor
c) To follow up with the hospital’s trace records
d) To confirm if a donor has been infected

b [Lookback starts with a donor → tracks recipients.]

Which virus is not effectively inactivated by solvent/detergent treatment of plasma?

a) HIV
b) HCV
c) HAV
d) HTLV

c [HAV is a non-lipid-enveloped virus, so it's resistant to these inactivation methods.]

Which transfusion-transmitted parasite is commonly associated with travel and mosquito exposure?

a) Toxoplasma gondii
b) Trypanosoma cruzi
c) Babesia microti
d) Plasmodium falciparum

D

What is the key lab test used to detect HCV RNA directly in blood donors?

a) ELISA
b) NAT
c) Western blot
d) Flow cytometry

b [Nucleic Acid Testing (NAT) detects viral RNA and helps shorten the window period.]

What is the difference between traceback and lookback in TTD investigations?

a) Traceback starts with a donor; lookback starts with a patient
b) Traceback is used only for bacterial contamination
c) Traceback starts with a patient; lookback starts with a donor
d) They are identical in process

c [Traceback = patient → donor; Lookback = donor → recipient]

Which virus is commonly latent and reactivates in immunocompromised patients, such as stem cell recipients?

a) HIV
b) CMV
c) EBV
d) Parvovirus B19

b [CMV stays dormant and can reactivate under immune suppression.]

Which TTD is caused by a prion and linked to contaminated human growth hormone treatments or beef products?

a) Toxoplasmosis
b) Babesiosis
c) Creutzfeldt-Jakob Disease (CJD)
d) Syphilis

c [CJD is a transmissible spongiform encephalopathy caused by prions.]

What is the best prevention for Chagas disease transmission via blood?

a) NAT testing
b) Vaccination
c) Bug eradication and donor history
d) Solvent-detergent plasma

c [No routine testing exists; preventing exposure and screening donors is key.]

A 64-year-old patient develops a high fever, hypotension, and signs of septic shock within 2 hours of receiving a unit of platelets. The unit appears discolored, and lab tests later confirm a gram-negative bacterial contaminant.

Q1. What is the most likely cause of this reaction?
a) Febrile non-hemolytic reaction
b) Transfusion-related acute lung injury (TRALI)
c) Bacterial contamination
d) Delayed hemolytic transfusion reaction

c [Rapid onset, platelets stored at room temperature, and septic signs are key clues.]

A donor is found to be positive for HBsAg and HBcAb on post-donation screening.

Q2. What is the next appropriate action?
a) Perform a traceback
b) Begin a lookback investigation
c) Retest the donor after 1 year
d) Discard the positive units and release the rest

b [Infected donor → lookback to identify any recipients of their blood.]

A patient develops a malaria-like illness after a transfusion. On questioning, the donor recently returned from a trip to sub-Saharan Africa.

Q3. What organism is most likely responsible?
a) Toxoplasma gondii
b) Plasmodium falciparum
c) Babesia microti
d) Trypanosoma cruzi

b

Match the disease to the correct description:

Disease	Description
A. CMV	1. Parasite transmitted by sandflies; rare in Canada
B. HIV	2. Reactivates in immunocompromised patients; use leukoreduced blood
C. Leishmaniasis	3. Retrovirus causing immunodeficiency; confirmed by Western Blot
D. Parvovirus B19	4. Non-enveloped virus; not inactivated by solvent/detergent treatment

• A → 2 (CMV reactivates and requires leukoreduction)

• B → 3 (HIV is a retrovirus, confirmed by WB)

• C → 1 (Leishmaniasis is spread by sandflies)

• D → 4 (Parvovirus B19 resists standard inactivation methods)

During mosquito season, a blood donor tests positive on NAT pooled sample for West Nile Virus (WNV). The sample is confirmed upon individual testing.

Q1. What is the next appropriate step regarding this donation?
a) Issue the component with caution
b) Retest the unit after 48 hours
c) Discard the unit and defer the donor temporarily
d) Send the unit for irradiation

c [WNV is transmissible via blood; positive units are discarded to protect recipients.]

A 40-year-old multiparous female donates plasma. The recipient of her donation later develops acute respiratory distress, and testing reveals the presence of anti-HLA antibodies in the donor.

Q2. What is the diagnosis and action for future donations?
a) Febrile reaction; donor can continue donating
b) TRALI; permanently defer donor from plasma donations
c) TACO; encourage slower transfusion
d) FNHTR; give acetaminophen to recipient in future

b [TRALI can be triggered by anti-HLA antibodies, common in women with multiple pregnancies.]

A donor from South America unknowingly carries Trypanosoma cruzi. A patient develops chronic cardiac issues months after transfusion.

Q3. Which disease is involved, and what is the prevention strategy?
a) Babesiosis; leukoreduction
b) Malaria; platelet filters
c) Chagas disease; donor history and regional screening
d) Toxoplasmosis; CMV negative blood

c; Chagas is caused by T. cruzi and is preventable through travel history screening.

Match each pathogen to its key feature or transmission mode:

Pathogen	Description
A. HTLV I/II	1. Linked to adult T-cell leukemia and tropical spastic paraparesis
B. Babesia microti	2. Tick-borne protozoan causing malaria-like illness
C. Epstein-Barr Virus	3. Herpes virus linked to infectious mononucleosis
D. Hepatitis B Virus	4. Transmitted via blood, sexual contact, and persists on surfaces for a week

• A → 1 (HTLV is associated with adult T-cell leukemia)

• B → 2 (Babesia causes malaria-like symptoms, spread by ticks)

• C → 3 (EBV = infectious mononucleosis, "kissing disease")

• D → 4 (HBV is highly stable and transmissible)

Which of the following is most commonly associated with Warm Autoimmune Hemolytic Anemia (WAIHA)?

a) IgM antibodies reacting below 30°C
b) IgG antibodies reacting at 37°C
c) Drug-dependent cold antibodies
d) Negative DAT

b [Warm AIHA is usually caused by IgG antibodies that react best at body temperature.]

Which of the following symptoms is most characteristic of Cold AIHA?

a) Splenomegaly and anemia only
b) Hemoglobinuria and acrocyanosis in cold weather
c) Petechiae and ecchymosis
d) Sore throat and skin rash

b (Cold AIHA often presents with cold-induced symptoms like blue fingers, hemoglobin in urine.]

In Drug-Induced AIHA, the DAT result is typically:

a) Positive with IgG only
b) Negative
c) Positive with complement only
d) Depends on the mechanism (hapten, immune complex, etc.)

d (Some drug-induced AIHAs show IgG or C3 depending on how the drug interacts with RBCs.)

A patient with Cold Agglutinin Disease has a DAT that is:

a) Negative
b) Positive with IgG
c) Positive with C3 only
d) Positive with both IgG and C3

c [Cold-reactive IgM fixes complement but is often not detected by the DAT itself.]

Which of the following is least likely a feature of Warm AIHA?

a) Splenomegaly
b) Polychromasia and spherocytes
c) Positive DAT with IgG
d) Hemolysis triggered by cold exposure

d [That’s more typical of Cold AIHA. Warm AIHA does not depend on temperature exposure.]

What is the treatment of choice for symptomatic Warm AIHA?

a) Plasmapheresis
b) Iron chelation
c) Corticosteroids
d) IVIG

c [Steroids are first-line therapy for warm AIHA to suppress antibody production.]

A patient develops fever, chills, back pain, and dark urine within 30 minutes of transfusion. What reaction is most likely?

a) Febrile non-hemolytic reaction
b) Acute hemolytic transfusion reaction (AHTR)
c) TACO
d) TRALI

b [Classic signs: rapid onset, hemoglobinemia/hemoglobinuria, flank pain.]

What is the most appropriate first step when any serious transfusion reaction is suspected?

a) Administer antihistamines
b) Stop the transfusion and keep IV open with saline
c) Call the blood bank in 30 minutes
d) Increase transfusion rate to flush the system

b [This is always the priority action to prevent further reaction.]

TRALI most often presents with which of the following signs?

a) Hypertension and jaundice
b) Urticaria and itching
c) Sudden respiratory distress and pulmonary edema
d) Fever and delayed bleeding

c [TRALI is non-cardiogenic pulmonary edema caused by leukocyte antibodies.]

Which patient is at highest risk of TACO (transfusion-associated circulatory overload)?

a) 25-year-old trauma patient
b) 18-year-old with ITP
c) Elderly patient with CHF
d) Healthy pregnant woman

c [At-risk groups include the elderly, children, and those with cardiac disease]

Which of the following is a key finding in febrile non-hemolytic transfusion reactions (FNHTR)?

a) Positive DAT
b) Hemoglobinemia
c) Fever >1°C rise, chills
d) Respiratory failure

c (FNHTRs are due to cytokine release from donor leukocytes.)

A 35-year-old woman with IgA deficiency develops hypotension, wheezing, and shock after transfusion. What is the most likely cause?

a) TRALI
b) Bacterial contamination
c) Anaphylactic reaction
d) Delayed hemolytic reaction

c [Often seen in IgA-deficient individuals with anti-IgA antibodies.]

Which of the following adverse reactions is classified as delayed and immunologic?

a) Citrate toxicity
b) Iron overload
c) Delayed hemolytic transfusion reaction (DHTR)
d) Allergic urticaria

c [Occurs 3–10 days post-transfusion due to anamnestic antibody response.]

What lab test is used to confirm an immune-mediated hemolytic reaction?

a) Hematocrit
b) ABO forward grouping
c) Direct Antiglobulin Test (DAT)
d) PT/INR

c [DAT detects antibodies or complement bound to RBCs.]

What is the treatment for Post-Transfusion Purpura (PTP)?

a) Iron supplements
b) Exchange transfusion or IVIG
c) Platelet transfusion
d) Corticosteroids only

b [PTP is caused by anti-platelet antibodies; IVIG is the mainstay of treatment.]

Which reaction is best prevented by using leukoreduced blood components?

a) Iron overload
b) Febrile non-hemolytic transfusion reaction
c) Anaphylactic reaction
d) Hemochromatosis

b (Leukoreduction removes donor white cells that cause cytokine release)