WVU NSG 460 Immunology I Exam 5 Content

What is the overall purpose of the immune system?

-to distinguish self from non-self

-we do this through our WBCs

Three Main Problems

Immune System Doesn't Work

-example: AIDS or immunosuppression

Immune System Attacks Itself

-example: autoimmune disorder

Immune System Goes Overboard

-example: anaphylaxis

Who is considered immunosupressed?

-chemotherapy patients

-infants

^their immune system has not developed fully

-geriatrics

^have immuno-depression as they age

White Blood Cells

-normal WBC: 5,000-10,000 (may see 5 to 10)

-have differentials

^this means there are various forms of WBCs within our body

Differentials

Eosinophils

-involved with allergic reactions (neutralizes histamine)

-digests foreign proteins

^a way I remember is E-osinophils are involved with E-llergic reactions

Basophils

-contain histamine

-integral part of hypersensitivity reactions

-deal with our T & B Cells

Neutrophils

-arrive to the site of action FIRST

-you know there is an issue occurring within the body if this lab level is elevated

T and B Cells

B-Cells

-show up and make antibodies

-build up defenses and encourage chemical mediators

^they way I remember this is antibodies remind me of bodyguards (bodyguards defend)

T-Cells

-natural killers

-they kill whatever is at the site

^the way i remember this is T stands for "take-em out"

Neutrophils/PMN

-most common WBC

-crucial for fighting bacterial infections

AIDS

-first recognized in 1981

-caused by a retrovirus, otherwise known as Human Immunodeficiency Virus (HIV)

-affects both cellular and humoral immunity

Estimates of HIV/AIDS in 2018

-37.9 million people have it (down from 2005 when it was 40 million)

-1.2 million people in the US had HIV at the end of 2018

-770,000 people have died from AIDS-related illnesses since the start of the epidemic

-15,820 people died in 2018

*everyday 1,000 children become HIV (+)

HIV/AIDS in Comparison with Other Diseases

Influenza

-1918 to 1919

-US death toll: 650,000

-world death toll: 100 million

-more people died in one year than have died from AIDS so far

COVID-19

-2020 to present

-US death toll: 552,000

-world death toll: 2.82 million

HIV

-must invade the "T" lymphocyte to reproduce

^attacks CD4 cells primarily

^replicates and destroys host cells

Two Enzymes are Crucial to the Reproduction Process

1. reverse transcriptase

2. protease

-while the virus proliferates, the human cell dies

-CD4 begins to drop

Transmission of HIV

-unprotected sexual contact

-blood or blood products

-pregnancy, delivery, and breastfeeding

Main Transmission Fluids

-blood

-semen

-breast milk

-vaginal fluids

Can mosquitos transmit HIV?

-no they cannot

The Clinical Course of HIV

Acute HIV Infection

-a few weeks after contraction

-increased risk of passing HIV to other individuals

-s/sx: fever, HA, sore throat, rash, malaise

^these symptoms are viral, so the person may not think it is in response to HIV

Asymptomatic HIV

-can last between 7 to 10 years

-followed by progressive destruction of CD4 and immunocompromise correlating with decline CD4 counts and increasing viral loads

-as CD4 levels drop below 500, pts become symptomatic with characteristic infections

Symptomatic HIV

-s/sx: HA, visual changes, frequent oral/vaginal yeast infections, diarrhea, zoster, and/or weight loss

*as CD4 decreases, the risk to contract opportunistic infections increases

Is symptomatic HIV the same as AIDS?

-no they are not the same

AIDS Defining Conditions

-esophageal candidiasis

-cytomegalovirus, pneumocystis jiroveci (PCP), and mycobacterium avium complex (MAC)

-cervical cancer

-toxoplasmosis encephalitis

-wasting syndrome

-TB

-CD4 count < 200

*if you are HIV (+) and have one of these, you have AIDS

PJP

-a lung disease caused by a common organism previously called pneumocystis carinii; it has been renamed p. Jiroveci

-it was originally thought to be a protozoan, but research has found that it is an atypical fungus

-it does not cause problems in people with health immune systems

What is a tell-tale sign of severe zoster?

-follows a dermatome

-should never cross midline of the spinal column

What disease is rare, but can occur in people with HIV/AIDS?

-Kaposi's Sarcoma

^occurs when you're immunosuppressed

Diagnostic Tests for HIV

ELISA

-cheap and quick

-can get a false (+)

-if you tested negative, you can follow up in 3 to 6 months (may be too early to show up as a positive)

Western Blot

-slower and more expensive

-more specific test

-not as many false (+)

Newest HIV Tests

-to help expedite the results of HIV tests and scale up HIV testing, AIDS antibody tests can provide results in under 20 minutes

-these tests detect antibodies in the blood or in saliva

-oral HIV tests work by swabbing the inside of the cheek and identifying antibodies in saliva

Other Diagnostic Tests for HIV/AIDS

CD4 Count

-predicts susceptibility to opportunistic infections (OIs)

-decreases with progression

Viral Load

-predictor of progression to AIDS

-increases with progression

Pharmacology Overview for HIV/AIDS

-multiple drug therapy

-HAART: highly active antiretroviral therapy

-never implement monotherapy

^type of therapy that only uses one type of medication

What are two medication types that are used to counteract HIV replication

-reverse transcriptase inhibitor agents

-protease inhibitors

Anti-Retroviral Agents (AIDS Medications)

Reverse Transcriptase Inhibitors

-Zidovudine (retrovir)

-formerly AZT

-can be used on pregnant women to block the transmission of the virus to the fetus

Protease Inhibitors

-INDINAVIR (crixivan)

*these ones are most commonly used

^limits the ability for the virus to replicate, and limits the destruction of WBCs

Goal of Antiretroviral Agents

-maintain a CD4 >500 and have an undetectable viral load

Integrase Inhibitors

Isentress (raltegravir)

-HIV's DNA must be incorporated into the CD4 cell's DNA

^this is known as integration

-as their name implies, integrase inhibitors work by blocking the process

*this medication is somewhat experimental

Enfuvirtide (fuzeon)

-prevents HIV from entering and taking over the cells in your body

-usually given after other medications have been tried without successful treatment of HIV

What is the main side effect of reverse transcriptase inhibtors?

-bone marrow supression

What is the main side effect of protease inhibitors?

-liver damage

Opportunistic Infections Overview

-correlate with the CD4 count

-reason for admission to the hospital/death

-unusual organisms

-treatment similar to non-AIDS patient

Examples of Opportunistic Infections

-TB

-toxoplasmosis

-PCP

-MAC

-herpes

-candida

Safersex.org

-the proper and consistent use of latex condoms when engaging in sexual intercourse (vaginal, anal, or oral), can greatly reduce a person's risk of acquiring STDs, including HIV infection

What precautions do we use when someone with HIV/AIDS is admitted to the hospital?

-standard precautions

Standard Precautions

-wash hands

-gloves for blood, excretions, and secretions

-mask, face, and eye shield if needed

-clean equipment, etc.

-sharps!

Three Questions for Health Care Worker Exposure

Exposure Code

-what substance? (blood, semen, vaginal fluid, etc.)

-how much of the substance?

Surface Exposed

-did it enter the eyes, mouth, nose, etc.

HIV Status Code

-source HIV (+) or (-)

Health Care Worker Exposure

-risk of contracting HIV from known HIV (+) patient with average needle stick is 1/300

-if treated with AZT/indinavir, it decreases your risk by half

-best treated within one hour

Post-Exposure Prophylactic

-consult recommendation (PEP)

-antiretroviral therapy if necessary (2 to 3 meds)

-can take one dose while source blood is being tested

-if single use diagnostic system (SUDS) is available, you can get results in 30 minutes