Ch. 16 Disorders of the Immune Response Flashcards
What is innate immunity?
Able to recognize self/non-self
Reacts to microbes
Leukocyes, macrophages, NKC
Complement system
What is adaptive immunity?
Responds to antigens
infection, tumor cells, transplanted cells
What does the complement system do?
Assists antibodies and phagocytes to destroy pathogens.
What are B-cells and what is their job?
They are a type of WBC that is part of the adaptive immune system.
They secrete antibodies.
What are T-cells and what is their job?
They are part of the adaptive immune system and they direct B-cell activity.
What is hypersensitivity?
Excessive or inappropriate activation of the immune response
The body is damaged by the immune response, rather than by the antigen (often called allergen)
What is type I hypersensitivity?
Commonly called “allergic reactions”
Systemic or anaphylactic reactions.
Local or atopic reactions
What are five examples of local or atopic reactions?
Rhititis (hay fever) Food allergies Bronchial asthma Hives Atopic dermatitis
What is anaphylaxis?
Systemic response to the inflammatory mediators released in type I hypersensitivity.
What chemicals are released during an anaphylactic response that cause vasodilation?
Histamine, acetylchiline, kinins, leukotrienes, and prostaglandins (all cause vasodilation)
What chemicals are released during an anaphylactic response that cause bronchoconstriction?
Acetylchonline, kinins, leukotrienes, and prostaglandins
What is type II hypersensitivity?
Cytotoxic response involving IgG or IgM that attack antigens on cell surfaces.
What are the three things that result from a type II hypersensitivity reaction?
- Cell lysis
- Results in inflammatory process
- Results in cell dysfunction
What is opsonization?
Cell lysis
What are three examplse of type II hypersensitivity reactions that result in cell lysis?
Transfusion reactions
Rh disease (hemolytic disease of the newborn)
Drug reactions
What are two examples of type II hypersensitivity reactions that result in inflammatory process?
Gomerulonephritis
Transplant reaction
What are two examples of type II hypersensitivity reactions that result in cell dysfunction?
Graves disease
Myasthenia gravis
What is type III hypersensitivity?
Circulating inactive antigen + antibody immune complex that deposit on the walls of blood vessels and activate complement.
What are four examples of type III hypersensitivity reactions?
Autoimmune vasculitis
Glomerulonephritis
Systemic lupus erythemoatosus (SLE)
Serum sickness
What is a type IV hypersensitivity response?
Cell-mediated: sensitized T cells attack antigen and cell is damaged as a result. This occurs even if the pathogen is not harming the cell.
What is an example of type IV hypersensitivity?
Some types of hepatitis
What is direct cell-mediated cytotoxicity?
Type IV hypersensitivity - Viral reactions
What is delayed-type hypersensitivity? (two examples)
Type IV hypersensitivity - tuberculin test, allergic contact dermatitis
What is self-tolerance?
The ability to differentiate self from non-self
What maintains self-tolerance?
Central tolerance (deletes T&B cells in thymus and bone marrow) Peripheral tolerance (deletes activated T&B)
What are autoimmune diseases?
When the autoimmune system is unable to differentiate and body tissues are destroyed (impaired self-tolerance)
What is “central tolerance” (what does it do)?
Deletes T&B cells (in thymus, bone marrow)
What is “peripheral tolerance” (what does it do)?
Deletes unnecessarily activated T&B cells (stops hypersensitivity reaction)
What are primary immunodeficiency disorders?
B-cell deficiencies T-cell deficiencies - CD4 helper - CD8 cytotoxic Combined immunodeficiencies
What is an acquired immunodeficiency disorder?
AIDS
What causes AIDS?
Human Immunodeficiency Virus (HIV) attacking CD4 T lymphocytes
How does HIV attack CD4 T lymphocytes?
Attaches to CD4 T cell receptors.
Enters cell.
Attaches own RNA to cell’s DNA.
Uses cell’s energy to reproduce more viruses.
What does AIDS result in? (5)
Profound immunosuppression Malignancies Opportunistic infections Wasting CNS degeneration
How is HIV transmitted?
Blood/body fluids
- pre-ejaculate, semen, vaginal fluid (not saliva or urine)
- Breast milk
- Blood to blood contact
What are three ways HIV can be transmitted by blood to blood contact?
Contaminated needles
Transfusions
During pregnancy or birth (in utero or labour and delivery)
What occurs during Stage 1 of HIV infection (Primary infection phase)?
Signs of systemic infection 1-4 weeks post exposure. (Typical signs of a viral infection, lasting 7-10 days)
Rapid viral replications decrease DC4 T-cell counts
What is seroconversion in HIV?
The immune system responds to the virus and antibodies against HIV appear. This takes 1-6 months.
What is the most contagious “window period” of HIV?
Primary stage, prior to seroconversion (first 1-6 months)
What occurs during Stage 2 of HIV infection (latent period)?
No signs/symptoms
Virus replicates
CD4 T-cell count decreases
Possible lymphadenopathy
What occurs during stage 3 of HIV infection (Overt AIDS)?
T-cell count is low
Death in 2-3 years without treatment
What are the three stages of AIDS?
Stage 1: primary phase
Stage 2: latent period
Stage 3: overt AIDS
What are opportunistic infections?
Infections caused by organisms that would normally not cause infection in a “healthy” person (without AIDS).
How are opportunistic infections categorized?
Categorized by organism type.
What three systems are often affected by opportunistic infections in a person with AIDS?
Respiratory
Gastrointestinal
Nervous system
What are the three typical opportunistic respiratory infections seen in a person with AIDS?
Bacterial pneumonia
P. Jiroveci pneumonia
Pulmonary tuberculosis
What are P. Jiroveci and P. Carinii?
They are both common fungus in the environment.
Multiply quickly in HIV infected lungs.
Foamy exudate form cysts in alveoli,
Manifestations: mild cough, fever, SOB, weight loss
What is the leading cause of death in HIV?
Tuberculosis
What organs can be infected by tuberculosis?
Usually lungs
Can also be kidneys, bone marrow, etc.
What are the manifestations of tuberculosis in an AIDS patient?
Fever
Night sweats
Cough
Weight loss
What are three typical gastrointestinal infections seen in individuals with AIDS?
Esophagitis
Aphthous ulcers (canker sores)
Gastroenteritis
What is esophagitis caused by? (3)
Esophageal candidiasis, chlamydial virus, herpes simplex
What are the manifestations of aphthous ulcers (canker sores)?
Pain (location)
Painful swallowing
Retrosternal pain (when in esophagus)
What is gastroenteritis?
Mild to severe diarrhea.
What does HANDS stand for?
HIV Associated Neurocognitive Disorders
What is HANDS?
Syndrome of cognitive and motor dysfunction, with behavioural and psychosocial symptoms.
What are the manifestations of HANDS?
Attention/concentration deficit, mental/motor slowing, apathy
What is toxoplasmosis?
A parasitic infection of the nervous system.
Parasite found in cat feces and raw meat.
What are the manifestations of toxoplasmosis?
Fever, headache, confusion, lethargy, visual disturbances, seizures
What is Progressive Multifocal Leukoencephalopathy?
Slow demyelination of white matter d/t virus
What are the manifestations of Progressive Multifocal Leukoencephalopathy?
Progressive limb weakness, hemi-paresis, ataxia
Sensory loss, visual disturbances
Mental status changes, seizures
What is Kaposi Sarcoma?
A common malignancy in AIDS patients of endothelial lining of blood vessels.
What are the manifestations of Kaposi Sarcoma?
Oral & skin lesions, GI tract, lungs Violet lesions enlarge, darken Often on trunk, neck, head, tip of nose Painless at first Invade tissue (late pulmonary invasion)
What are four common malignancies found in AIDS patients?
Kaposi Sarcoma
Non-Hodgkin lymphoma
Cervical carcinoma
Anal carcinoma
What is wasting syndrome?
Diagnosed in absence of opportunistic infection or malignancy. (In AIDS patients)
What causes wasting syndrome?
Malabsorption, endocrine dysfunction, etc.
What are the manifestations of wasting syndrome?
Involuntary weight loss >10% of baseline body weight
Diarrhea, multiple daily stool
Chronic weakness
Fever
What are some metabolic disorders that accompany AIDS?
Insulin resistance, diabetes, hyperlipidemia, lipodystrophy, mitochondrial disorders
What causes metabolic disorders in AIDS patients (most often)?
Treatment regimens (side effects)