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Flashcards in Immunology Deck (30)
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1

A 48-year-man with chronic renal failure undergoes a cadaveric renal transplant. One week later, the patient has an elevated creatinine level. The surgical team is concerned about the possibility of acute transplant rejection. The cell type shown in the image is believed to be an important mediator of this process. In which of the following locations does this cell type complete maturation?

Thymus. Acute rejection is one complication of kidney transplantation. In acute rejection, the principal mediator is believed to be the cytotoxic T lymphocyte. Activated cytotoxic lymphocytes invade the tubular interstitium of the transplanted kidney, leading to tubulitis. In contrast, chronic rejection is mediated by antibody complex formation. Elevated creatinine levels allow early detection of acute rejection in the absence of clinical signs, which may include graft tenderness, oliguria, and fever. T lymphocytes mature in the thymus, where they undergo positive and negative selection. 

2

A 23-year-old man comes to the physician with a bacterial infection. On questioning the patient reveals a history of recurrent bacterial, fungal, and viral infections. Blood is drawn and sent for laboratory analysis, which reveals all levels of immune cells (eg., T lymphocytes, B lymphocytes) are low. Which of the following conditions is most likely to have caused the patient’s symptoms?

Severe combined immunodeficiency is a defect in early stem cell differentiation that can have many causes and leads to a total lack of a cellular immune system. The typical presentation of this disease includes recurrent bacterial, viral, protozoal, and fungal infections.

3

A 13-year-old boy is diagnosed with a hyperactive immune system. Normally an antigen will activate the immune system to trigger a pro-inflammatory response. Following the proinflam-matory response, anti-inflammatory signals then dampen the immune response to prevent it from causing damage. This patient has trouble dampening the immune response after it is no longer needed. Decreased activity in which of the following anti-inflammatory cytokines is most likely the basis for this boy’s condition?

Transforming growth factor- β. Mounting a strong immune response is crucial for the body to be able to fight off infections. However, reducing this response once the infection has been warded off is critical in order for the body to maintain its normal balance. Transforming growth factor- βis the cytokine that is responsible for dampening the immune response after it is no longer needed.

4

A 19-year-old man comes to the physician with a bacterial infection. Without treatment, the patient’s immune system will most likely be able to fight off the infection within a few days. One of the tools the patient’s body uses against the organism is the membrane attack complex. The membrane attack complex functions as which of the following?

A proteinaceous pore in the plasma membrane.The C5b, 6, 7, 8 complex guides the polymerization of C9 molecules in lipid bilayer of the target cell’s plasma membrane. C9 polymers form pores in the membrane, allowing the passage of ions andsmall molecules into the cell, causing the cell to lyse

5

To assess the risk of erythroblastosis fetalis occurring during the future pregnancy of an Rh-negative woman, a clinician sends a sample of serum for detection of anti Rh-blood group antibodies. The laboratory performs an indirect Coombs’ test by mixing the patient’s serum with Rh-positive RBCs and then adding an anti-IgG antibody. In doing so, the laboratory technician observes agglutination of the RBCs. After receiving this test result, the clinician would be correct to conclude which of the following?

The presence of anti-Rh antibodies in the patient’s serum suggests that she has been pregnant with an Rh-positive fetus When an Rh-negative mother gives birth to an Rh-positive fetus, fetal RBCs may enter the mother’s circulation, and the body may recognize the Rh antigen as

foreign and produce antibodies against it. As

maternal IgG freely crosses the placenta, any

subsequent Rh-positive fetus is at risk for hemo-

lytic disease. Thus, the indirect Coombs’ test is

an important laboratory tool to monitor for Rh

incompatibilities that may complicate fetal

health. The test result given in this question in-

dicates that the patient possesses anti-Rh anti-

bodies in her serum. Therefore, it would be

logical for the clinician to suspect previous

pregnancy with an Rh-positive fetus.

6

A newborn child is exposed to

Streptococcus

agalactiae

and subsequently develops meningi-

tis. Which of the following could have contrib-

uted to this child’s bacterial infection?

7

Haemophilus infl

uenzae

and

Neisseria menin-

gitidis

both possess a polysaccharide outer cap-

sule. Effective vaccination against these species

results in the generation of antibodies that rec-

ognize this polysaccharide capsule. Which of

the following best explains why the childhood

vaccines for

H. infl

uenzae

type B and

N. men-

ingitidis

serogroup C are composed of a poly-

saccharide coat conjugated to a protein car-

rier?

8

A type B blood group, Rh-positive recipient is

mistakenly transplanted with a kidney from a

type A blood group, Rh-negative donor. Which

of the following best describes the mechanism

of transplant rejection that is most likely to en-

sue in this recipient?

9

A 12-year-old girl is brought to the pediatrician

by her mother because of a fever. The physi-

cian notes that the girl has features of albinism

and the mother states that her daughter has al-

ways looked the way she does. The physician

diagnoses the girl with a staphylococcal infec-

tion and prescribes a course of antibiotics.

Three months later, the child returns to the pe-

diatrician with another streptococcal infection.

The patient’s medical records indicate that she

has had repeated bouts of staphylococcal and

streptococcal infections for her entire life. This

patient most likely has which of the following

types of immune defi

ciency?

10

A 60-year-old post-menopausal woman presents

with fatigue, mild jaundice, and tingling in the

lower extremities. Laboratory studies show ele-

vated serum levels of homocysteine and methyl

malonic acid, and complete blood cell count

shows a mild thrombocytopenia. Which of the

following fi ndings would be expected on a pe-

ripheral blood smear from this patient?

11

Antigen processing and presentation within the

context of a major histocompatibility complex

(MHC) class I molecule is essential to generat-

ing a CD8

+

T-lymphocyte response. In which of

the diagramed subcellular locations is the self-

peptide loaded onto MHC class I molecules?

12

A 7-year-old boy presents to the clinic with a

staphylococcal infection. He is well known at

the clinic because he has had recurrent staphy-

lococcal infections for most of his life. He is

started on an antibiotic regimen and the infec-

tion subsides. Three weeks later, the boy is di-

agnosed with pruritic papulovesicular dermati-

tis. Which of the following immune defi

ciency

syndromes would account for this patient’s re-

current staphylococcal infections and pruritic

papulovesicular dermatitis?

13

Hyper-IgM syndrome usually presents with se-

vere pyogenic infections. The typical immuno-

globulin profi le in a patient with this disease

shows an elevated level of IgM in contrast to

the other immunoglobulin isotypes. Which of

the following is the etiology behind the in-

creased level of IgM in a patient with hyper-

IgM syndrome?

14

A 40-year-old man presents to his physician

with numbness and tingling on the dorsal sur-

face of his right hand and forearm and raised

“varicose veins” that are fi rm to the touch

along the same distribution. He also complains

of weight loss. His serum creatinine level is 2.0

mg/dL. He has no previous medical history of

signifi

cance. An immune complex disease is

suspected, and assays for autoantibodies in

neutrophils are conducted. What diseases are

associated with the identifi cation of anti-my-

eloperoxidase and anti-proteinase-3 antibodies,

respectively?

15

A 32-year-old man with Hodgkin’s lymphoma

is scheduled to undergo a bone marrow trans-

plant. HLA typing of his immediate family

shows that his identical twin brother is a suit-

able match for harvesting an allogenic bone

marrow graft. This type of graft can be classi-

fi ed as which of the following?

16

Patients sharing similar clinical symptoms and

disease pathology may nevertheless present dif-

ferently based upon age at disease onset. Adult-

onset rheumatoid arthritis (RA) and juvenile

rheumatoid arthritis (JRA) are both the result

of infl ammatory processes. How does the pre-

sentation of JRA differ from the presentation of

adult-onset RA?

17

A 37-year-old man comes to the physician with

recurrent viral infections. Blood studies show

normal levels of circulating lymphocytes and

neutrophils. A defi ciency in which of the fol-

lowing cytokines would most likely lead to this

man’s condition?

18

Cluster of differentiation (CD) antigens are

glycoproteins present on the cell surface of

many cell types involved in the immune sys-

tem. They are recognized by monoclonal anti-

bodies and aid in the identifi cation of various

cell types. Which of the following glycopro-

teins is present on the cell surface of all thymo-

cytes: helper T-cells, cytotoxic T-cells, and nat-

ural killer cells?

19

A 2-year-old girl with a lifelong history of mal-

absorptive and foul-smelling diarrhea, weak-

ness, and general failure to thrive has just un-

dergone a small intestine biopsy (see image).

Her parents believe her problems began at 6

months of age, when she started eating solid

foods, but have signifi cantly worsened over the

past few months. The only recent change in

her diet is that she eats a bowl of cereal every

morning with her parents before they go to

work. She tried a dairy-free diet a month ago,

but it did not improve her symptoms. Which of

the following is the most likely diagnosis

20

A pediatrician becomes concerned after learn-

ing the family and medical history of an infant

who is currently suffering from pneumonia,

with a presumed diagnosis of

Streptococcus

pneumoniae

infection. Over the past year, the

patient has suffered from erysipelas as well as a

previous bout of pneumococcal pneumonia;

both were treated successfully with antibiotics.

The patient’s mother says that her son’s mater-

nal uncle also suffered from repeated bacterial

infections and was successfully treated with an-

tibiotics. On physical examination, it appears

that the patient does not have tonsils. His

mother denies a previous tonsillectomy. Analy-

sis of the boy’s serum would most likely yield

which of the following results?

21

A 25-year-old man presents to his doctor with a

2-day history of blood in his urine. A kidney bi-

opsy is obtained. When the tissue is stained

with fl uorescent anti-IgG antibodies, the stain-

ing reveals a linear pattern. Which of the fol-

lowing is the most likely diagnosis?

22

A clinician is concerned that an Rh-negative

mother may be pregnant with an Rh-positive

fetus. The potential pathology that the clini-

cian is concerned about is classifi ed as which

of the following immune reactions?

23

A 14-year-old boy presents to the physician with

recurrent pyogenic infections. Physical exami-

nation shows that the boy has pruritic papulo-

vesicular dermatitis. Blood is drawn and sent for

laboratory evaluation of platelets and immuno-

globulin levels. The results show a markedly low

platelet count, a low serum IgM level, and an

elevated IgA level. This patient most likely has

which of the following conditions?

24

A 32-year-old woman comes to the emergency

department complaining of sudden blindness.

On obtaining a thorough history, it is learned

that the patient’s right leg has “given out” from

time to time, causing the patient to have epi-

sodes of weakness and falling. Periventricular

white matter plaques are found on MRI.

Which of the following cells are primarily

damaged in this disease?

25

Women have about a 2.7 times greater lifetime

risk of developing at least one autoimmune dis-

ease than men. Which of the following state-

ments, if true, would support the higher rate of

systemic lupus erythematosus in women than

in men?

26

A 2-year-old boy is brought to the physician by

his parents because of recurrent sinus infec-

tions. The parents also state that the boy has

had multiple lung infections. Which of the fol-

lowing results would most likely be found on

further testing?

27

A 50-year-old man presents to his clinician be-

cause of bilateral itching, burning, and redness

of the lower extremities. He states that he wore

shorts while gardening outside his house re-

cently and could have come in contact with

poison ivy. Which of the following statements

regarding this patient’s immune response is

most correct?

28

Antibodies are one of the major players in the

adaptive immune response. All antibody mole-

cules consist of two heavy chains and two light

chains, and the specifi

c type of heavy and light

chain will determine the antigen binding site.

In all antibodies, the two heavy chains and the

two light chains are identical. Like most pro-

teins, much of their functional capabilities and

antigen binding characteristics stem from their

three-dimensional structure. Which of the fol-

lowing holds the heavy and light chains to-

gether to make the three-dimensional structure

of the antibody?

29

A 23-year-old woman comes to the physician

for a routine checkup. She has generally been

well over the past year, although she notes that

she has “had a few falls lately.” On physical ex-

amination, the lesion shown in the image is

found on her skin. Blood is drawn for labora-

tory evaluation. The results show that the

woman has very low levels of IgA. Based on her

presentation, this patient will most likely also

present with which of the following symptoms?

30

A 50-year-old man comes to the physician with

hemoptysis and diffuse joint pain. He states

that both his father and cousin had similar

symptoms and were diagnosed with micro-

scopic polyangiitis, a disease affecting medium-

to small-sized arteries that is believed to have

an autoimmune component to its pathogene-

sis. Which of the following autoantibodies

might be present in this patient?