Porth Chapter 16 Flashcards
Characteristics of AIDS
Profound immunosuppression
Associated opportunistic infections
Malignancies
Wasting
Central nervous system degeneration
AIDS Epidemic and Transmission of HIV
Caused by HIV
Occurs worldwide
There is no cure.
Transmitted through blood, semen, vaginal fluids, and breast milk
Not spread by casual contact or insects
Is infectious, even if the person is asymptomatic
Cells Affected by the HIV
A subset of lymphocytes called CD4+ T lymphocytes (also known as T-helper cells or CD4+ T cells)
Macrophages
Dendritic cells
Functions of the CD4+ T Cells
Necessary for normal immune function
Recognizes foreign antigens
Helps activate antibody-producing B lymphocytes
Orchestrates cell-mediated immunity
Influences the phagocytic function of monocytes and macrophages
Life Cycle of the HIV-1
Attachment of the HIV to CD4+ receptor
Internalization and uncoating of the virus with viral RNA and reverse transcriptase
Reverse transcription, which produces a mirror image of the viral RNA and double-standard DNA molecule
Integration of viral DNA into host DNA using the integrase enzyme
Transcription of the inserted viral DNA to produce viral messenger RNA
Translation of viral messenger RNA to create viral polyprotein
Cleavage of viral polyprotein into individual viral proteins that make up the new virus
Assembly and release of the new virus from the host cell
Three Phases of HIV Infection
Primary infection phase
Chronic asymptomatic or latency phase
Overt AIDS phase
CDC HIV/AIDS Classification System
The clinical importance of the CD4+ cell count in the categorization of HIV-related clinical conditions
Category 1: >500 cells/μL
Category 2: 200 to 499 cells/μL
Category 3: <200 cells/μL
Unique Opportunity for Treatment in the Primary Infection Phase
Reduce the number of long-living HIV-infected cells (e.g., CD4+ memory cells)
Protect the functioning of HIV-infected CD4+ T cells and cytotoxic T cells
Help maintain a homogeneous viral population that will be better controlled by antiretroviral therapy and the immune system
Typical progressors
60% to 70% acquire AIDS 10 to 11 years after infection
Rapid progressors
10% to 20% progress rapidly and acquire AIDS in less than 5 years
Slow progressors
5% to 15% are slow progressors, who do not progress to AIDS for more than 15 years
Long-term nonprogressors
1% have been infected for at least 8 years, are antiretroviral naive, have high CD4+ cell counts, and have usually very low viral loads
Consequences of CD4+ Death
Opportunistic infections
Malignant tumors
Nervous system manifestations
The wasting syndrome
Metabolic disorders
Bacterial Opportunistic Infections
Bacterial pneumonia, TB, Salmonella bacteremia, Mycobacterium avium–intracellulare complex (MAC)
Fungal Opportunistic Infections
Candidiasis, coccidiomycosis, cryptococcosis, and histoplasmosis