2.5.2 Diseases of Leukocyte Adhesion

Question 1

What is the role of CD18?

Answer 1

Adhesion of leukocytes to endothelial cells

Question 2

What is another term of CD21?

Answer 2

CR2

Question 3

What is another term of CD95?

Answer 3

Fas

Question 4

Answer

Answer 4

C

Question 5

What cell type represents the greatest fraction of the white blood cell count?

Answer 5

Neutrophils

Question 6

What is the role of G-CSF?

Answer 6

Stimulation of neutrophil production

Question 7

What type of bacteria induce a strong neutrophil response?

Answer 7

Pyogenic bacteria

Question 8

The neutrophil ligand CD15s (sialyl-Lewis) binds to what on endothelial cells?

Answer 8

CD62E (e-selectin) and CD62P (P-selectin)

Question 9

GlyCAM-1 and CD34 on the endothelium bind to what on the neutrophil?

Answer 9

CD-62L (L-selectin)

Question 10

What carries out the integrin-mediated tight adhesion?

Answer 10

CD11a/CD18 (LFA-1) and CD11b/CD18 (Mac-1, CR3) bind to CD54 (ICAM-1) and CD102 (ICAM-2) on the endothelium

Question 11

What carries out the process of diapedesis for neutrophils?

Answer 11

CD31 (PECAM-1) expressed by the emigrating neutrophil interacts with CD31 expressed at the endothelial cell-cell junction.

Question 12

What are some chemoattractants for neutrophils?

Answer 12

C5a, leukotrienes, and IL-8

Question 13

How can an infection change the distribution of neutrophils in the body?

Answer 13

Infection will cause neutrophils to be more in the tissue.

Question 14

How can epinephrine change the distribution of neutrophils in the body?

Answer 14

It can increase the circulating pool of neutrophils

Question 15

Steroids will have what effect on the distribution of neutrophils?

Answer 15

It will increase the circulating pool of neutrophils. Leading to slight depression of neutrophils in the bone marrow.

Question 16

What is the cause of neutropenia resulting from peripherial pooling?

Answer 16

Acute endotoxemia

Question 17

What are some causes of decreased production of neutrophils resulting in neutropenia?

Answer 17

Drug induced, aplastic anemia, folate deficiency, and Chediak-Higashi syndrome

Question 18

What are some common causes of neutrophilia?

Answer 18

Glucocorticoids, infection, inflammation, epinephrine, and stress

Question 19

What is chronic granulomatous disease?

Answer 19

Loss of a subunit of NADPH oxidase leading to decreased phagocyte function of neutrophils

Question 20

What is Chediak-Higashi Syndrome?

Answer 20

Reduced phagolysosome fusion

Defective egress from marrow

Question 21

What is the underlying cause of LAD - Type 1?

Answer 21

CD18 deficiency

Question 22

What is the underlying cause of LAD - Type 2?

Answer 22

Reduced expression of Sialyl-Lewis

Question 23

Test result of phagocytosis of fresh serum-opsonized staph is very low, what can this indicate?

Answer 23

There is a problem with complement-mediated phagocytosis

Question 24

What are these flow cytometry results indicative of?

Answer 24

Patient does not have any CD11 or CD18 protein.

Question 25

After review of these flow cytometry results what is a probable diagnosis?

Answer 25

LAD - Type 1 resulting from a CD18 deficiency. Neutrophils cannot adhere to the endothelium.

Question 26

Patient presents to clinic with numerous cotton-ball densities, and upon fine needle aspiration Apergillus fumigatus is cultured. Testing for reduction of dihydrorhodamine following C5a is impaired. What can be a possible cause?

Answer 26

There is a problem with the oxidative burst pathway. Particularily in NADPH oxidase. Chronic granulomatous disease.

Question 27

Would a patient with myeloperoxidase deficiency present in the same way a patient with chronic granulomatous disease would?

Answer 27

No, myeloperoxidase is downstream in the oxidative burst, so most bacteria can be taken out by the first two steps of the pathway. These patients can appear asymptomatic.