Chapter 19: Disorders Associated with the immune system

Question 1

Hypersensitivity

Answer 1

Immune system functioning and targeting NORMAL, but giving an undesirable response. (Excessive immune response)

Question 2

Autoimmunity

Answer 2

Immune system is functioning and targeting ABNORMALLY. (attacking self cells)

Question 3

Types of Hypersensitivity:
> Type l:

Answer 3

> > Anaphylactic Hypersensitivity:
- Less than 30 min.
- IgE binding to mast cells causes histamine release
- Localized anaphylaxis: Asthma, food allergies, hay fever
-Systemic anaphylaxis: bee stings, food (causes anaphylactic shock).

B cell activity

Question 4

Types of Hypersensitivity:
> Type ll:

Answer 4

> > Cytotoxic Hypersensitivity:
- 5-8 hrs.
- IgG + IgM causing MAC attack.
- ex. Rh factor newborn disease, thrombocytopenic purpura

Requires B cell activity; linked specifically to IgG

Question 5

Types of Hypersensitivity:
> Type lll:

Answer 5

> > Immune Complex Hypersensitivity:
- 2-8 hrs
- Antibody-antigen complex
- ex. serum sickness

** B cell activity
linked specifically to IgG**

Question 6

Types of Hypersensitivity:
> Type IV:

Answer 6

> > Delayed Hypersensitivities
- 1-2 days
- T cell response
- Causes cell lysis
- Ex. poison oak, poison ivy, cheap metal in jewelry.

dependent only on T cell activation

Question 7

How does the body normally respond to an injected antigen during a type l hypersensitivity?

Answer 7

Systemic anaphylaxis. Dilation of blood vessels and decrease of blood pressure. Fatal in minutes.

Question 8

Hygiene hypothesis

Answer 8

The idea that if a child is present in an environment that is too clean, he won’t have the opportunity to be exposed to many antigens, which would allow the immune system to develop by teaching the body (cell memory) to recognize pathogens and trigger a response. Being too clean can result in H & A’s.

Question 9

Types of autoimmunity:
> Type I:

Answer 9

> > Cytotoxic reaction:
- Antibodies bind to self antigens and cause cell death
Ex. Hemolytic anemia ( causes hemolysis)

Question 10

Types of autoimmunity:
> Type II:

Answer 10

> > Cytotoxic reaction:
- Antibodies bind to self antigens but do not kill, cell function altered.
Ex. Grave’s disease

Question 11

Types of autoimmunity:
> Type III:

Answer 11

> > Immune Complex Autoimmunity:
- Formation of large number of immune complexes that leads to tissue damage.
Ex. rheumatoid arthritis

Question 12

Types of autoimmunity:
> Type IV:

Answer 12

> > Cell-Mediated Reaction:
- Self- reactive CD8+ T cells kill cells of the body.
Ex. Psoriasis

Question 13

How are TH17 CD 4+ T cells related to the autoimmunities?

Answer 13

Cause excessive inflammation.

Question 14

What are a few suspected causes of hypersensitivity and autoimmunity?

Answer 14

• Presence of industrial pollutants
• Results of being too clean

Question 15

How does the hygiene hypothesis connect with H & A’s?

Answer 15

Being too clean does not allow the body to encounter pathogens to train the body and create memory cells.

Question 16

Is the immune system functioning normally during immunodeficiency?

Answer 16

No, some or all not working properly

Question 17

What are the two most common immunodeficiencies?

Answer 17

> Congenital: Disorders are inherited (selective IgA deficiency= frequent mucosal infections).

> Acquired: Disorders are not inherited (leukemia).

Question 18

What does the abbreviation SCID stand for?

Answer 18

Severe Combined Immunodeficiency
(Most severe immunodeficiency: 1 in 100,000)

Question 19

How does SCID affect the immune system?

Answer 19

A congenital immunodeficiency disorder. A mutation that results in the complete loss of B and T cells.

Question 20

What are the structural characteristics of HIV?

Answer 20

> Human Immunodeficiency Virus:
1. Virion is enveloped.
2. Virion has glycoprotein spikes.
3. Virion contains 2 pieces of ssRNA genome.
4. Virion contains the enzyme reverse transcriptase.

(starts as 2 ssRNA then double stranded dna)

Question 21

Which type of HIV is common in North America: U.S and Mexico?

Answer 21

HIV I, Group M, clade B.

Question 22

What allows HIV to change over the course of an infection?

Answer 22

Enzyme reverse transcriptase: creates stable cDNA

Question 23

What are the human host cell receptor and coreceptors that allow HIV to infect?

Answer 23

CD4 and Coreceptor for attachment is either CCR5 or CXCR4

Question 24

Which specific immune cell types are infected by HIV?

Answer 24

• CD4+ T cells
• Macrophages
• Dendritic cells

Question 25

How is the life cycle of HIV distinct from other viral families?

Answer 25

Gets in the cell and never leaves: provirus.

Question 26

Which body organ becomes infested with large amounts of HIV?

Answer 26

Lymph nodes

Question 27

How is HIV most likely to be transmitted?

Answer 27

Transfer of contaminated body fluids.
Blood, semen, saliva.

Question 28

HIV- Phase I:

Answer 28

> > Asymptomatic Phase:
- You have normal count of T cells (1000-800 CD4+ Tc)
- Might exhibit an early Acute Retroviral Symptom “ARS” (flu like sympt. 2-4 weeks after exposure.
- Circulating antibodies appear 1-10 weeks after infection
- ARS is followed by latent period lasting months/years

Question 29

HIV- Phase II:

Answer 29

> > Symptomatic Phase:
- Infections by opportunistic pathogens are more common.
- Shows early indication of immune system failure.
- Most HIV still latent
-800-200 CD4+ Tc

Question 30

HIV- Phase III:

Answer 30

> > AIDS (Acquired immunodeficiency syndrome)
- CD4+ Tc 200 or less
- Viral load is at least 100k viral mRANs per 1 ml blood plasma
- HIV infection progresses to AIDS in 10-12 years if left untreated.

Question 31

How does T cell number relate to disease progression?

Answer 31

T cell count goes down as disease progresses.
1. 1000-800 CD4+ Tc
2. 800-200 CD4+ Tc
3. CD4+ Tc 200 or less

Question 32

What is a noticeable indicator that HIV infection has progressed to phase 2?

Answer 32

Opportunistic pathogens become more common

Question 33

What does the abbreviation HAART stand for?
Why is treatment with HAART a challenge in developing countries?

Answer 33

> > Highly Active Antiretroviral Therapy.
keeps viral load to 0, meaning it cannot be transferred and stays in phase 1.

Too expensive.

Question 34

Which state has the most new HIV infections?

Answer 34

Florida

Question 35

Which state contains the greatest number of people living with HIV infections?

Answer 35

New York

Question 36

In the US, who is most at risk for becoming infected with HIV?

Answer 36

Homosexual/bisexual men.

Question 37

Globally, who is most at risk for becoming infected with HIV?

Answer 37

Adults (women)

Question 38

Difference between a person that is HIV positive and a person who has AIDS:

Answer 38

A person infected with HIV (phase 1) is not considered a person with AIDS. A person with HIV is considered to have progressed to AIDS when: the number of their CD4 cells falls below 200. The viral load is very high at this 3rd phase. AIDS is the disease caused by the damage that HIV does to your immune system