Immune System Flashcards
Discuss the function of immune system / Compare and contrast the innate and adaptive immunity / Discuss the cells involved in innate and adaptive immunity / Discuss the etiology, pathogenesis, clinical manifestations of HIV & AIDS / Discuss other immune disorders like hypersensitive disorders
1
Q
Immune System
Any foreign substance that does not have the characteristic cell surface markers of an individual and is capable of eliciting an immune response = ?
A
Antigens: Any foreign substance that does not have the characteristic cell surface markers of an individual and is capable of eliciting an immune response.
- Antigens are recognized by specific receptors present on them by lymphocytes/ antibodies
2
Q
Immune System
Produced in response to an antigen, are protein molecules structured in such a way that they only interact with the antigen that induce their synthesis = ?
A
Antibody: Produced in response to an antigen, are protein molecules structured in such a way that they only interact with the antigen that induce their synthesis
3
Q
Immune System
Two distinct and specialized processes of immunity= ?
A
(1) Innate immunity (natural/ native)
- First responders to insult
- Response is rapid and same at all times
- Nonspecific: does not distinguish between different types of invaders (bacteria, virus)
- Non adaptive: does not remember the previous encounter
(2) Acquired / adaptive immunity
- Slower response; when reintroduced then rapid and intense immune response
- Diversity: Recognize and destroy foreign material like bacteria, fungi
- Specificity: targeted response to a distinct antigen
- Memory: when same organism enters again, body respond’s more rapidly to it and with a stronger reaction
- Self and non-self-recognition
4
Q
Immune System
How can adaptive immunity be acquired ?
A
Active adaptive immunity can be acquired in different ways:
- Active acquired immunity
- Development of antibodies in response to an antigen
- Introduction of antigen by either naturally from environmental exposure or artificially by vaccination
Passive acquired immunity:
- When antibodies produced by one person are transferred to another person either naturally (mother to fetus) or inoculation of antibody
Adaptive / Acquired Immunity
5
Q
Immune System
How does passive acquired immunity occur ?
A
Passive acquired immunity:
- When antibodies produced by one person are transferred to another person either naturally (mother to fetus) or inoculation of antibody
Adaptive / Acquired Immunity
6
Q
Immune System
T and B cells migrate throughout the body through ?
A
- Humoral = B cells
- Cell mediated = Tcells
- Response from these two types of immunity overlap andinteract considerably.
- T and B cells migrate throughout the body via blood, lymph, and lymph nodes.
Adaptive / Acquired Immunity
7
Q
Immune System
Humoral / B Cells = ?
A
Humoral / B Cells:
- Involving antibodies / immunoglobulins
- B lymphocytes: originate and mature in bone marrow
- B cells are very effective against organisms that are free floating in the body that can very easily be reached and neutralized.
- B lymphocyte-plasma cellcan produce5 types of antibodies
- IgG
- IgM
- IgA
- IgD
- IgE
8
Q
Immune System
T lymphocytes originate in ?
A
(a) T lymphocytes:
- Originate in bone marrow andmature in Thymus
- T cells can recognize the hidden organisms, searchthem out and destroy on acell-to-cellbasis
- Helper T cells (T4 lymphocyte, CD4 lymphocyte), 75% of T cells
- Assist B cells to mature and produce antibodies
- Activating macrophages and helping them destroy large bacteria
- Helping other T lymphocytes (cytotoxic T cells/ CD8 cells) recognize and destroy virally infected cells
- HIV destroys these helper T cells and leaves the body at risk of infections
- Suppressor T cells: suppresses the activation of immune system
- Cytotoxic T cells (CD8): Toxic to the antigens; killing the antigens
- Memory T cells: Remember what they crossed paths with in the body
Cell Mediated Immunity: T Cells
9
Q
Immune System
Factors altering the immune system = ?
A
- Aging
- Nutrition:
- Deficits in calories, protein intake or vitamins like A and E can cause deficiency in T cell function and numbers.
- Zinc deficiency: impairs T and B cell function
- Burns:
- Decrease external defense, decrease neutrophil function, decreased cell mediated and humoral responses
- Sleep disturbances
- Presence of concurrent illness and disease like malignancy, diabetes, HIV infection
- Drugs:
- Immunosuppressive drugs, cancer chemotherapeutic drugs suppress the immune response
- Surgery / anesthesia:
- Suppresses T and B cell function up to 1 month post operatively (Splenectomy).
10
Q
Immune System
Central immune structures include bone marrow and the thymus.
- What are their functions in regard to immune defense = ?
Function of Immune Defense Components
A
Bone Marrow:
- Production of lymphocytes
- Maturation of B lymphocytes
Thymus:
- Gland located in the mediastinum
- Differentiation and maturation of lymphocytes
11
Q
Immune System
Peripheral immune structures include lymphnodes, spleen, and other lymphatic mucosal tissues such as the tonsils, peyer patches, appendix.
- What are their functions in regard to immune defense = ?
A
Lymphnodes:
- Round masses of lymphatic tissue
- Spread out among lymphatic vessels
Spleen:
- Site of lymphatic migration
Lymphatic mucosal tissue (tonsils, peyer patches, appendix):
- Site of lymphatic aggregation
12
Q
Immune System
The primary cellular components involved in immune defense include T Lymphocytes and B Lymphocytes.
- What are their functions in regard to immune defense = ?
A
T Lymphocytes:
- Matured in thymus
- Essential in adapative cell-mediated immunity
- Desctruction of cellular antigens
- Promote antibody production by B Lymphocytes
- Account for 60% of blood lymphocytes.
B Lymphocytes:
- Matured in bone marrow
- Essential in mediating adaptive humoral immunity
- Production of antibodies/immunoglobulins
- Account for 10-20% of blood lymphocytes
13
Q
Immune System
Accessory cellular components involved in immune defense include:
- Macrophages
- Neutrophils
- Dendritic cells
What are their functions in regard to immune defense?
A
Macrophages:
- Essential in mediating innate immunity
Neutrophils:
- Bind invading microbes to cell surface receptors
Dendritic cells:
- Process and present antigen to T and B lymphocytes, stimulating adaptive immune response.
- Phagocytosis to prevent colonization, entry, and spread of microbes
14
Q
Immune System
What should we know about exercise immunology?
A
- Depending upon the intensity, activity or exercise can enhance or suppress the immune function.
- Moderate intensity exercise- enhances immune system = 50-70% of the maximal heart rate.
- Strenuous/ intense/ long duration exercise impairs the immune system= Leave host open to microbial agents during open window
15
Q
Immune System
Impact of exercise on:
- Neutrophils
- NK cells, and
- Lymphocytes
A
Neutrophils:
- Exercise: rise in blood levels of neutrophils.
- After brief gentle exercise- count returns to baseline.
- After strenuous exercise- return to normal may take 6-24 hours.
NK cells:
- Once the person is accustomed to a given exercise level, the NK enhancement falls off.
- After intense exercise, number and activity of NK cells decline, maximum reduction occurs 2-4 hours after the exercise, return to baseline soon
Lymphocytes:
- Increase but decrease below normal for several hours after intense exercise
16
Q
Immune System
Primary and secondary immunodeficiency disorders result from ?
A
(a) Immunodeficiency disorders:
- Immune response is absent / depressed
- B cell, T cell, combined B and T cell deficiency, NK cells, phagocyte cells.
(b) Primary: Defect involving the cells
- Genetic
(c) Secondary: Results from an underlying disease / factor:
- HIV-AIDS
- Malnutrition/ alcoholism
- Ageing
- Autoimmune disease
- Cancer
- Steroids
- Chemotherapy
- Radiation therapy
17
Q
Immune System
AIDS = ?
- What does it infect?
A
- Infection of immune system, resulting in progressive and profound immune suppression
- Infects selectively CD4 (cluster of differentiation) helper T lymphocytes, dendritic cells and macrophages
- Characterized by progressive destruction of T cell mediated immunity and changes in humoral immunity
- Resultant immunodeficiency- opportunistic infections including unusual cancers, tuberculosis
18
Q
Immune System
AIDS Pathophysiology
A
- Transmitted through blood-blood contact, sexual contact (semen, vaginal secretions), perinatally (amniotic fluids, breast milk)
- Infection can occur across mucosal surfaces including vagina, cervix and anus
(a) High risk behaviors =
- Unprotected anal/ oral / vaginal sex
- Sexual activity with someone known to carry HIV
- Injecting drugs
- Blood transfusions
(b) Risk factors
- Poverty
- Illegal drug use
- Not good access to health care system
19
Q
Immune System
HIV is a _ virus?
(genetic material in RNA)
A
- HIV is a retrovirus (genetic material in RNA).
- Attacks CD4+ T lymphocytes cells, destroys and inactivates them; macrophages and dendritic cells are also affected.
- HIV has high mutation rate even within a single individual, to fight for survival.
Pathogenesis
20
Q
Immune System
9 steps in HIV Pathogenesis = ?
A
- Binding of virus to CD4+ cells after it enters the blood steam
- Fusion and contents of the viral core enter host cells
- Reverse transcription, genetic information of the virus from viral RNA to double stranded DNA, Reverse transcriptase
- Integrated into host DNA and replicated many times
- Transcription: double stranded DNA to single stranded RNA
- Translation: proteins
- Assembly: new HIV proteins and RNA assemble and move to the surface of the cells
- Budding and release of mature virion
- HIV replication: killing of CD4+ cells- release of HIV copies into the bloodstream- viral particles invade other CD4+ cells- infection progresses
21
Q
Immune System
HIV infection involves full spectrum illness:
- Asymptomatic HIV seropositive CD4 count = ?
- Symptomatic HIV count = ?
- HIV advanced disease (AIDS) count = ?
A
(a) HIV infection involves full spectrum illness:
- Asymptomatic HIV seropositive (positive for HIV antibodies; CD4 count > 500 cells/mm^3
- Symptomatic HIV (CD4 count between 200-500 cells/mm^3
- HIV advanced disease (AIDS) < 200 cells/mm^3
(b) CDC definition of AIDS =
- HIV-1 (type 1 retrovirus) and CD4 lymphocyte count below 200 (normal: 600-1200)
- Development of opportunistic infections
22
Q
Immune System
Asymptomatic HIV disease: CD4 > or = ?
A
(a) Asymptomatic HIV disease: CD4 > or = 500 cells/mm3
- Positive for antibodies
- Asymptomatic between 1-20 years
- Clinically healthy, normal ADLs, unrestricted level and duration of exercise
- Fatigue, swollen and firm lymph glands
23
Q
Immune System
Symptomatic HIV disease
CD count between = ?
A
(a) Symptomatic HIV disease
- CD count between 200-500 cells/mm3.
- Viral load goes up and CD4 count goes down
- Generalized adenopathy (swollen lymph nodes)
- Nonspecific symptoms like diarrhea, weight loss, fatigue, night sweats, fever, report fatigue that limits physical and exertional activities, opportunistic infections as cell mediated immunity is low, pneumonia
24
Q
Immune System
HIV advanced disease (AIDS), CD4+ cell count = ?
A
(a) HIV advanced disease (AIDS)
- CD4+ cell count = <200 cells/mm3
(b) Neurologic involvement (central, peripheral, autonomic)
- HIV encephalopathy (gait disturbances, intention tremors)
- HIV associated dementia (apathy, lethargy, social withdrawal, depression, memory impairment)
- Peripheral neuropathies: pain, sensory loss, motor deficits, gait disturbances
Opportunistic infections:
- P. carinii pneumonia (fungal infection of lungs, risk for pneumonia, cough, shortness of breath, fever)
- Malignancies (Kaposi sarcoma, lymphoma)
25
# *Immune System*
Clinical manifestations of HIV advanced disease (AIDS) include ?
(a) **Dermatologic conditions**:
* Hair loss
* Rash
* Delayed wound healing
* Bacterial, viral infection, fungal infections, dry flaking skin, thinning of skin/ hair
(b) **Kaposi Sarcoma**:
* Cancer that forms in the lining of blood and lymph vessels
* lesions to grow in the skin, lymph nodes, internal organs, and mucous membranes lining the mouth, nose, and throat
* Painless purplish spots are common signs
* + Pain associated with HIV infection, immunosuppression, opportunistic infections, comorbidities
(c) **Pain syndromes**:
* Painful peripheral neuropathy, arthralgia's (joint pain/ swelling)
* Myalgias (muscle aches/pain)
* Abdominal pain, chest pain.
* + Musculoskeletal pain syndromes associated with HIV wasting syndrome unwanted weight loss of more than 10 percent of a person's body weight
* weight loss, diarrhea, weakness, fever, mineral/ vitamin deficiencies
(d) Neuro-musculoskeletal diseases: osteomyelitis, myositis, arthritis, myopathy
(e) **Lipodystrophy**:
* Defective fat metabolism, dyslipidemia (elevated cholesterol/ fat), insulin resistance, visceral and central fat deposition in abdomen, breasts, back; loss of fat in arms, legs and face.
* Side effect of treatment
26
# *Immune System*
Antigen produced with HIV infection = **?**
**P24** is the antigen produced with HIV infection.
27
# *Immune System*
HIV/AIDS treatment = **?**
* No cure, current medications decrease the amount of virus in the body.
* **HAART**: highly active antiretroviral therapy – recommended
* Disease went from death sentence to chronic illness
* Resistance to drug therapy is the primary concern
* According to the symptoms NSAIDS and pain medications
* Vaccines under investigation
28
# *Immune System*
Keys to HIV and rehabilitative therapy = **?**
(a) Management of physical dysfunctions
* Functional capacity is reduced
* Low intensity exercise
* + Regular exercise encouraged
(B) Collaborate with physician
* Pain control
* Energy conservation
* Maximize functional ability
(c) Address impairments / limitations
* Progressive resistance exercise
* Avoid strenuous exercise
* Recovery periods will be longer
* Monitor the response to exercise
* Acute polymyositis/ myopathy: avoid strenuous/ resisted exercise
* Acute inflammatory arthralgia- joint protection and rest
* Individual with advanced HIV – immuno-deficient- prevent infection for that person
29
# *Immune System*
Post exposure prophylaxis
(a) **Occupational exposure**:
* Urgent medical concern
* Call CDC/ state health, medical evaluation, counselling, antiretroviral medications, follow up.
(b) **PEP**:
* Consist of 28 day course of ***HAART***, initiated within hours.
* Advised to use precautions to prevent secondary transmission esp, during the first 6-12 weeks of post exposure (avoid blood/ tissue donations, breastfeeding or pregnancy).
30
# *Immune System*
Abnormal and excessive response of the activated immune system that causes injury and damage to the tissues = **?**
**Hypersensitivity Reactions / Allergy**:
* Abnormal and excessive response of the activated immune system that causes injury and damage to the tissues.
* Response varies from mild, to severe, and potentially life threatening.
* Allergens = pollen, dust, food products, drug components.
31
# *Immune System*
4 classifications of hypersensitivity disorders = **?**
4 classifications of hypersensitivity disorders:
**Type 1**:
* IgE mediated
**Type 2**:
* IgG, IgM mediated
**Type 3**:
* IgG, IgM mediated
* Antigens and antibodies
* Lupus
**Type 4**:
* T cell mediated
* TB skin test reactions
32
# *Immune System*
Classifications of Hypersensitivity Disorders:
* Type 1 = **?**
Classification of Hypersensitivity Disorders:
**Type 1: IgE mediated**
* Most common, immediate
* Develops rapidly upon exposure (first-second exposure), classic allergic response (inflammation - histamine released - dilation and bronchospasm - edema, rash, difficulty breathing, asthma, diarrhea, allergic rhinitis, itchy watery eyes).
* Severe - anaphylactic shock - BP drops and airways narrow.
* Treatment: antihistamines, corticosteroids, epinephrine (Epipen, constrict blood vessels).
33
# *Immune System*
Classifications of Hypersensitivity Disorders:
* Type 2 = **?**
Classifications of Hypersensitivity Disorders:
**Type 2: IgG, IgM mediated**
* Antibody mediated
* Directed against target antigens on specific host cell tissues
* Basis of autoimmune diseases
**Autoimmune Disorders - Type 2**:
* **Addison’s disease**: A disorder where the adrenal glands don't produce enough hormones, leading to symptoms like fatigue, weight loss, and low blood pressure.
* **Crohn’s disease**: An inflammatory bowel disease causing inflammation in the digestive tract, leading to symptoms like abdominal pain, diarrhea, and weight loss.
* **Type 1 diabetes mellitus**: A chronic condition where the pancreas produces little to no insulin, requiring lifelong insulin injections for blood sugar control.
* **Polymyositis/dermatomyositis**: Autoimmune diseases causing inflammation of muscles (polymyositis) and skin (dermatomyositis), leading to muscle weakness and skin rashes.
* **Thyroiditis**: Inflammation of the thyroid gland, affecting thyroid function and potentially causing symptoms like fatigue, weight changes, and mood swings.
* **Ulcerative colitis**: An inflammatory bowel disease causing inflammation and ulcers in the colon, leading to symptoms like abdominal pain and bloody diarrhea.
* **MS (Multiple Sclerosis)**: A neurological condition where the immune system attacks the protective covering of nerves, causing communication problems between the brain and the rest of the body.
* **MG (Myasthenia Gravis)**: A neuromuscular disorder causing muscle weakness and fatigue, often affecting the eyes and facial muscles.
* **RA (Rheumatoid Arthritis)**: An autoimmune disease causing joint inflammation, pain, and deformity.
34
# *Immune System*
Classifications of Hypersensitivity Disorders:
* Type 3 = **?**
Classifications of Hypersensitivity Disorders:
**Type 3: IgG, IgM mediated; complement mediated**:
* Example: formation of antigen-antibody immune complexes in the blood stream, later deposited in vascular epithelium or extravascular tissues.
* Massive inflammatory response - injury.
**Systemic Lupus Erythematosus** (SLE):
* Type 3 systemic reaction, autoimmune disease - autoantibodies against self antigens - binding of antigens with antibodies.
* Antigen antibody complex deposition and inflammation.
* Chronic systemic disease that can damage a wide range of cell types and locations, symptoms depend upon location.
* Women common.
35
# *Immune System*
Classifications of Hypersensitivity Disorders:
* Type 4 = **?**
Classifications of Hypersensitivity Disorders:
**Type 4: T cell mediated**:
* Delayed (TB skin test)
* Transplant rejection
36
# *Immune System*
Systemic Lupus Erythematosus:
* Clinical features = **?**
* Treatment = **?**
**Systemic Lupus Erythematosus** (SLE):
* There are exacerbations and quiescence ( = inactivity or dormancy).
**Common organs affected**:
* Skin
* Kidneys
* MSK
**Less commonly affected**:
* Neurologic
* Pulmonary
* Cardiac
**Clinical Features** (C/F):
* Joint pain
* Swelling
* Arthritis
* Skin rashes (butterfly rash)
* Pericarditis
* Pericardial effusion
* Pleural effusion
**Treatment**:
* Anti-inflammatory: NSAIDs
* Immunosuppressive: corticosteroids
