Pathogenesis of AIDS Flashcards

1
Q

How are individuals staged after diagnosis of HIV?

A

Stage 0: early infection, recognized by HIV-test within 180 days of first HIVG+ test (acute retroviral syndrome)
Stage 1 - 3 based on age-specific CD4 t-cell count

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2
Q

Which stage is considered to be AIDS?

A

stage 3

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3
Q

Which two stages have no AIDS defining conditions?

A

Stage 1 and 2

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4
Q

When can staging be bi-directional?

A

When there is no AIDS-defining condition present

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5
Q

What are the phases of HIV infection?

A

1 Acute retroviral syndrome (weeks)

  1. Chronic HIV (years -decades)
  2. Aids (months to years)
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6
Q

In chronic HIV in which tissues are viruses trapped?

A

lymphoid tissue

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7
Q

During asymptomatic phases the HIV patient is not infectious. (T/F)

A

False. highly infectious

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8
Q

What are the most common presentation?

A

constitutional

Lymphatics

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9
Q

While in clinical latency, how does the viral load change in the blood?

A

load increase

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10
Q

What is AIDS dementia?

A

when the virus crosses the blood-brain barrier

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11
Q

What happens due to the loss of CD4 cells during chronic HIV?

A

loss of control of nonlymphoid cells, loss of DTH response»»control of bacteria, fungi and virus

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12
Q

What happens to the macrophages and dendritic cells during chronic HIV?

A

-macrophages carry HIV into CNS
-excess secretion of cytokines in lymph noes
Decreased:
- antigen presentation
-MHCII expression
chemotaxis
phagocytica ability
cytotoxic ability

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13
Q

What happens during AIDS dementia complex (ADC)?

A
memory loss
impaired cognition
impaired motor function
behavioral changes
apathy
depression
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14
Q

When does ADC (AIDS dementia complex) typically occur?

A

as CD4 count falls to < 200 cells/microliter

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15
Q

How does HIV evade the immune system?

A
  • antigenic drift of gp120 (evades antibody detection)
  • heavy glycosylation of gp120 (evasion of antibody detection)
  • infection of lymphocytes and macrophages (inactivation of ley element of immune defense)
  • inactivation of CD4 helper cells (loss of activator of the immune system and delayed-type hypersensitivity)
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16
Q

What is a rapid progressor?

A

AIDS in 2-3 years (probably CCR5)

17
Q

What is a typical progressor?

A

AIDS in 10 years

18
Q

What is a long-term nonprogressor

A

low HIV levels; normal CD4 cell; >10 years after HIV positive
HIV-2 (CXCR4)- less virulent

19
Q

What are the implications of R5 vs. X4 infection?

A

R5-(M-tropic) macrophages and DC are persistently infected
CD4 cells lyse - deplete Tcells in GALT

X4 - (T-tropic) occurs late and there is a change in receptor preference to CSCR4

  • mutation in env gene for gp120 shifts this tropism
  • development of AIDS
20
Q

Do some people possess natural immunity? why?

A

1 -CCR5-delta32 mutation
CXCR4 mutation
2 -HLA B57 - produce larger number of killer T Cells
3 - Some acquire specific immune defenses
4 - frequent sexual exposure to HIV