PATHO EXAM 1: HIV AND IMMUNE SYSTEM

What is HIV?

- retro virus

- slow progressing disease

- two main types: HIV1 (most common in US); HIV -2 (limited to west africa)

What is the transmission route of HIV?

• Blood

• Semen

• Vaginal fluids

• Transplacenta

• Breast milk

• Saliva (into open mouth wounds)

What cells does HIV attack?

CD4 cells and macrophages

How does HIV slowly debilitate the bodies immune system?

by attacking both T and B cell Immunity (humoral and cell- mediated immune reactions)

What cell servers as a reservoir for HIV?

macrophages; allows the virus to go undetected

What helps HIV spread?

macrophages since they are found in mucus membranes

What type of illness is HIV driven by?

its an enzyme driven illness

What cell does HIV attach itself too?

CD4 receptor cell

Reverse transcriptase

changes viral RNA into viral DNA

Integrase

allows viral DNA to be integrated into host DNA

Protease

helps assemble protein components to build new viruses

what happens to the cell once HIV take over?

- host cell becomes a factory for manufacturing more viruses

- after using host cell, the virus destroys the CD4 cell causing a weakend immune response

Who is most at risk of HIV?

- heterosexual females who have unprotected sex

- men who have sex with men (receptive partner)

Which men are most at risk for HIV?

hispanic and black men

Who is also at risk of HIV?

IV drug abusers

someone with a history of STD

frequent blood transfusions

offspring of infected mothers

what are the stages of HIV infection?

acute infection, chronic infection, and AIDS

Acute phase

• Presents like a flu-like virus

• similar to mononucleosis

• Symptoms include fever, headache, fatigue, pharyngitis ,lymphadenopathy, myalgia

• Occurs within 28 days of contracting the virus

• Lasts a couple of weeks and then resolves

• Symptoms are often disregarded

• After this stage resolves the patient becomes asymptomatic

-HIGHLY CONTAGIOUS AT THIS STAGE AND VIRUS IS REPRODUCING RAPIDLY

Why is HIV so hard to treat at an acute phase?

the person becomes asymptomatic after symptoms present themselves as a a common cold or flu. The virus can remain dormant in CD4 cells which is why it makes it hard to treat at an early stage.

Chronic Phase

• Known as the latent stage

• Can last from 6 months to 10 years

• Symptoms can range from mild to severe:

• Symptoms: Cough• Shortness of breath• Weight loss• Diarrhea• Fatigue

• Viral load is slowly increasing (virus is reproducing much slowly)

• CD4 count is decreasing

- STILL transmittable

AIDS phase

- CD4 count diminishes to 200 or less (leaves PT immunocompromised)

- symptoms: rapid weight loss, recurring fever or profuse night sweats, red rash that doesn't itch in the torso area, prolonged swelling of the lymph glands in the armpits, groin, or neck.

What are some complications of AIDS?

-kaposi sarcoma

-pneumocystis jirovecii pneumonia ( 75% of PT get this)

- other opportunistic infections

How do we diagnose HIV?

HIV RNA blood test

How long does it take for HIV to be detected in the bloodstream?

4-11 days after infection

What is considered low risk of HIV in a blood test?

less than 10,000 HIV RNA

what is considered at risk for HIV in a blood test?

more than 10,000 HIV RNA

How long does it take the immune system to develop antibodies to HIV?

2 weeks and 6 months

What is the most accurate measurement of impaired immune system?

- CD4 count

- If CD4 count drops below 200 cells/mm3 AND there is anopportunistic infection, then the diagnosis of AIDS ismade.

Normal CD4 count range

800- 1,200 cells/mm3

Impaired immunity CD4 count range

below 500 cells/mm3

How is HIV treated?

Antiretroviral therapy (ART) is the only long-term successful treatment

• Medications work by attacking the virus at various stages• Examples: protease inhibitors,transcriptase inhibitors, integraseinhibitors, fusion inhibitors

• Treatment be started as soon as possible

• Can live a long life if compliant withmedications

Why is treatment hard for HIV?

-latency phase

- immunocompromising patient

- HIV is a highly mutable virus

What are some common opportunistic infections HIV/AIDS patients get?

• Tuberculosis

• Candida (thrush)

• Pneumocystis jiroveci pneumonia (PJP)

• Toxoplasmosis

• Histoplasmosis

• Hepatitis A, B, C

what are some common cancerous seen in HIV patients?

• Kaposi sarcoma

• Non-Hodgkin's lymphoma

• Cervical cancer

• Anal cancer

PREP- PRE EXPOSURE PROPHYLAXIS

Uses antiviral medications in highly susceptible, uninfected individuals

• Examples: Truvada, Descovy

• Strategy used when one partner is HIV positive, and the other is HIV negative

• Must take the medication every single day

• Continue to use condoms

• Follow up with their health care provider every 3 months

PEP (post exposure prophylaxis)

• Uses antiviral medications after a single high-risk event to prevent contraction of HIV

• Must be started within 72 hours to be effective

• Includes a 28-day course of triple ART

-emergency use only! no long term

What cells are present in both adaptive and innate immunity?

T cells and Natural killer cells

what is the goal of adaptive immunity?

• recognize self from non-self (antigen)

• recognize and target a specific antigen

• limit its response

• development memory for future exposures (specificity)

Humoral B cell immunity

• Immunity is developed by B lymphocytes producing antibodies

• B cells are naïve or immature until they encounter antigens.

• After exposure to an antigen, B cells mature into plasma cells.

• Plasma cells have the ability to produce specific proteins called immunoglobulins (Igs), also called antibodies.

• Support is provided by helper T cells to help promote/escalation of immune response

-mature in bone marrow, spleen, and lymph nodes

-protect against extracellular pathogens

What are antibodies?

also called immunoglobulins

-Ex: IgG, IgA, IgE, IgM, IgD

• Specifically recognize and bind to particular antigens

Cell-mediated (T-cell) immunity

• Immune response without the use of antibodies

• Uses macrophages, T-lymphocytes, and cytotoxic cells for a direct approach at pathogen destruction

• Antigen provokes antigen presenting cell (APC) which processes antigen

• Stimulates T-helper cells and activates macrophages

• Antigen fragments are put on the surface of the APC, triggering CD8 cells known as cytotoxic cells

• CD8 cells destroy cell via apoptosis

- mature in the thymus gland

- found in the bloodstream and lymph nodes

protects against intracellular pathogens

active acquired immunity

• Obtained through exposure to an antigen or through immunization(vaccine).

• The patient's body has to synthesize specific immunoglobulins against an antigen.

• Either the patient contracts a disease and develops Igs and then recovers or the patient is given a vaccine.

• Both endow long-term immunity.

passive acquired immunity

• Pre-manufactured immunoglobulins are given or passed down.

• The body passively accepts immunoglobulins and the body DOES NOT have to manufacture them

.• This is short-term immunity.

• Administered when the patient needs IMMUNITY NOW because of being with close contacts or a family member who has the virus.

• Example: hepatitis B immunoglobulin(Hbig) and immunoglobulins in breast milk

What is a booster?

This is a repeated vaccine administered some time after the initial vaccine in order to"remind" the body to make immunoglobulins.

Antibody titer

confirm adequate immune protection by measuring IgM and IgG immunoglobulins

What does a negative titer mean?

• They have not been exposed to disease

• Never developed immunity

• Need vaccination/booster