USMLE World-based Heme/Onc

Question 1

Deficiency causing hemolytic anemia due to failure of glycolysis and resultant failure to generate sufficient ATP to maintain RBC structure –> splenic hypertrophy due to increased work of splenic parenchyma that removes deformed RBCs from circulation

Answer 1

Pyruvate kinase deficiency

Question 2

Hematologic parameter not affected by methemoglobinemia

Answer 2

O2 partial pressure is a measure of O2 dissolved in plasma and is not related to hemoglobin function

Question 3

What type of mutation causes HbC?

Answer 3

Missense mutation (glutamate –> lysine in beta globin chain)

Question 4

Enzymes involved in the non oxidative reactions of HMP shunt

Answer 4

Transketolase

Transaldolase

Question 5

Mutation three bases upstream from the start codon (AUG) of the beta globin gene

Answer 5

Thalassemia intermedia; mutation interferes with mRNA binding to ribosomes

Question 6

Disseminated mycobacterial dz in infancy or early childhood

Answer 6

interferon-gamma signaling pathway defects

Question 7

recurrent lower respiratory tract and Giardia infections

Answer 7

X-linked agammaglobulinemia (XLA)

Question 8

Recurrent infections with encapsulated organisms

Answer 8

C3 deficiency

Question 9

Recurrent infections with Neisseria

Answer 9

C5-9 deficiency (components of MAC)

Question 10

delayed separation of the umbilical cord, recurrent cutaneous infections without pus formation, poor wound healing

Answer 10

Leukocyte adhesion deficiency

Question 11

Process that occurs in naive B-cells on initial exposure to antigen. It is primarily induced by CD40’s interaxn w/ its ligand and IL4 & IL5

Answer 11

Isotype switching

Question 12

infant w/ chronic diarrhea, failure to thrive, low T + Ig counts

Answer 12

SCID (x-linked, adenosine deaminase)

Question 13

hosts prevent reinfection w/ influenza with

Answer 13

anti-hemagglutinin IgG in circulation and mucosal anti-hemagglutinin IgA antibodies in nasopharynx

Question 14

Where does VDJ (heavy chains) + VJ (light chains) recombination occur?

Answer 14

Bone marrow

Question 15

Where does isotope switching occur

Answer 15

germinal centers of lymph nodes

Question 16

What do interferons alpha and beta do?

Answer 16

in response to viral infxn, tell neighboring cells to decrease protein synthesis

Question 17

what does inferno gamma do?

Answer 17

produced by NK and T cells; promotes TH1 differentiation, induces CLass II HMC expression, and activates macrophages

Question 18

What prevents systemic Candida infection?

Answer 18

Neutrophils

Question 19

CD14

Answer 19

macrophages

Question 20

obliterative vascular fibrosis of a donor kidney

Answer 20

chronic rejection

Question 21

CD55 + CD59 deficiency

Answer 21

PNH