2.5.3 AIDS and Other Secondary Immune Deficiencies Flashcards
Is a CD4 level of 74 in a patient that is positive for HIV uncommon?
No
What is this an image of?
Pneumocystis jirovecii
What are risk factors of acquiring HIV/AIDS?
IV drug use and multiple partners
What are the qualifying criteria for diagnosing a patient with AIDS?
CD4 T cell count less than 200 and an AIDS defining illness
How does HIV infection begin?
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.
What is the mechanism of which HIV infects T cells?
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
What is the effect of HIV on DCs?
Decrease in number and function during primary HIV infection. Partial restoration with antiretroviral therapy.
What is the role of HIV and TLRs?
HIV activates DCs via TLR7 and 8. This increases cytokinds and also increases PDL-1 which binds to PD-1 on T cells
How can HIV infection affect NK cells?
This infection can lead to changes in NK gene expression, loss of function and increased cell death
How does HIV infection affect CD4 T cells?
HIV infected T cells have decreased triggers for proliferation, decreased IL-2, decreased IL-2R (CD25) expression, and decreased CD28
How can HIV affect CD8 T cells?
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
How can HIV infection lead to up-regulation of inflammation?
Elevated levels of pro-inflammation cytokines: IL-1, IL-6 and TNF-alpha
Th17 loss - important in gut mucosal immunity
The glycan shield on HIV protects it from what?
Prevents antibody binding
Can diabetes affect the immune system?
Yes, poor circulation can lead to poor lymphocyte infiltration.
What is the immune dysfunction that arisies due to a protein losing condition?
CVID
How can steroids affect immunity?
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
How can steroids affet leukocyte trafficking?
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.
How can steroids affects neutrophils?
Severely impair their migration into the tissues leaving them in the vasculature
How can steroids affect monocytes and macrophages?
Inhibition of phagocytic and microbicidal function - less killing and clearance
Decrease antigen presentation.
How can steroids affect eosinophils?
Promotion of apoptosis by attenuation of IL-5
How do steroids affect DCs?
suppression of antigen presentation - decreased MHC II
How do steroids affect T cells?
Lead to rapid depletion of T cells. Inhibit IL-2 production and IL-2 signaling and Induction of apoptosis.
Where can steroids be useful?
Autoimmune disease and GvH disease
Where can steroids be harmful?
Increased risk of infection and poor response to vaccination
What is Rituximab?
Monoclonal antibody against CD20
Why would a person with depleted B cells from Rituximab still be able to fight infection well?
Rituximab does not target plasma cells, so there are memory antibodies that can fight against most infections.
