2.5.3 AIDS and Other Secondary Immune Deficiencies

Question 1

Is a CD4 level of 74 in a patient that is positive for HIV uncommon?

Answer 1

No

Question 2

What is this an image of?

Answer 2

Pneumocystis jirovecii

Question 3

What are risk factors of acquiring HIV/AIDS?

Answer 3

IV drug use and multiple partners

Question 4

What are the qualifying criteria for diagnosing a patient with AIDS?

Answer 4

CD4 T cell count less than 200 and an AIDS defining illness

Question 5

How does HIV infection begin?

Answer 5

Dendritic cells are believed to be infected at the mucosal site. The infected DC then migrates to LN.This allows HIV to then infect CD4+ cells.

Question 6

What is the mechanism of which HIV infects T cells?

Answer 6

gp120 binds to cellular receptor CD4 causing a conformational shift and binding of coreceptor CCR5 or CXCR4. This allows the fusion into the host and then reverse transcriptase creates DNA from HIV RNA

Question 7

What is the effect of HIV on DCs?

Answer 7

Decrease in number and function during primary HIV infection. Partial restoration with antiretroviral therapy.

Question 8

What is the role of HIV and TLRs?

Answer 8

HIV activates DCs via TLR7 and 8. This increases cytokinds and also increases PDL-1 which binds to PD-1 on T cells

Question 9

How can HIV infection affect NK cells?

Answer 9

This infection can lead to changes in NK gene expression, loss of function and increased cell death

Question 10

How does HIV infection affect CD4 T cells?

Answer 10

HIV infected T cells have decreased triggers for proliferation, decreased IL-2, decreased IL-2R (CD25) expression, and decreased CD28

Question 11

How can HIV affect CD8 T cells?

Answer 11

HIV can mutate so the CD8 T cells lack recognition on MHC I. Higher expression of PD-1 may affect the CTL ability to respond

Question 12

How can HIV infection lead to up-regulation of inflammation?

Answer 12

Elevated levels of pro-inflammation cytokines: IL-1, IL-6 and TNF-alpha

Th17 loss - important in gut mucosal immunity

Question 13

The glycan shield on HIV protects it from what?

Answer 13

Prevents antibody binding

Question 14

Can diabetes affect the immune system?

Answer 14

Yes, poor circulation can lead to poor lymphocyte infiltration.

Question 15

What is the immune dysfunction that arisies due to a protein losing condition?

Answer 15

CVID

Question 16

How can steroids affect immunity?

Answer 16

Decreasing IL-1

IkB enhancing leading to inactivation of NF-kB

Diminish stability of mRNA for IL-1, 2, 6, 78, TNF, and GM-CSF

Question 17

How can steroids affet leukocyte trafficking?

Answer 17

It can reduce adherence to vascualr endothelium caused by direct effects on expression of adhesion molecules on leukocytes and endothelial cells. Indirect effects on cytokine inhibition.

Question 18

How can steroids affects neutrophils?

Answer 18

Severely impair their migration into the tissues leaving them in the vasculature

Question 19

How can steroids affect monocytes and macrophages?

Answer 19

Inhibition of phagocytic and microbicidal function - less killing and clearance

Decrease antigen presentation.

Question 20

How can steroids affect eosinophils?

Answer 20

Promotion of apoptosis by attenuation of IL-5

Question 21

How do steroids affect DCs?

Answer 21

suppression of antigen presentation - decreased MHC II

Question 22

How do steroids affect T cells?

Answer 22

Lead to rapid depletion of T cells. Inhibit IL-2 production and IL-2 signaling and Induction of apoptosis.

Question 23

Where can steroids be useful?

Answer 23

Autoimmune disease and GvH disease

Question 24

Where can steroids be harmful?

Answer 24

Increased risk of infection and poor response to vaccination

Question 25

What is Rituximab?

Answer 25

Monoclonal antibody against CD20

Question 26

Why would a person with depleted B cells from Rituximab still be able to fight infection well?

Answer 26

Rituximab does not target plasma cells, so there are memory antibodies that can fight against most infections.