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MMG Autoimmune Disease


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What are the four hypersensitivites?
*List from Type 1= 1, etc
1) Immediate hypersensitivity
2) Cytotoxic hypersensitivity
3) Immune-Complex Mediated hyperseneitivity
4) Delayed or cell-mediated hypersensitivity
How do malfunctions of immune system cause morbidity or martality?
*by overreaction or underreaction
-autoimmune diseases
-immunodeficiency diseases
What cells are involved in Type 1 hypersensitivity?
-mast cells, basophils, and eosinophils
-red blood cells
-activated T cells
Describe Type I hypersensitivity.
-localized (common) or systemic reactions that result from the release of inflammatory olecules in response to an antigen
-develop within seconds or minutes of antigen exposure (allergens)
What are some locations for localized allergic reactions?
-inhaled: respiratory tract response or lungs)
-local dermatitis
How do you treat allergic, localized reactions?
What is bad about systemic reactions in an allergic reaction?
-life threatening!
what happens in systemic allergic reactions?
-degranulation of many mast cells at once= release of lots of histamine and inflammatory mediators!
What can result from systemic allergic reactions?
-acute anaphylaxis or anaphylactic shock
What are signs of anaphylactic shock?
-bronchial smooth muscle contracts violently
-leakage of fluid from blood vessels may cuase swelling of laynx and other tissues
-contraction of smooth muscles of intestines and bladder
How do you treat systemic allergic reactions?
-treat promptly with epinephrine!
When does Type II hypersensitivity occur?
-results when cells are destroyed by an immune response
-often due to combined activites of complement and antibodies
Which Hypersensitivity is a component of many autoimmune diseases?
-Type II
What are two examples of Type II hypersensitivity?
-destruction of blood cells after incompatable blood transfustion
-destructions of fetal red blood cells in hemolytic disase of newborn
What type of blood is the universal donor?
What are the two antigens found in blood?
-A and B
How do complications arrive from wrong blood being donated?
-donors antigens atimulate production of antibodies in recipient which bind and destroy transfused cells by macrophage and neutrophil-based phagocytosis and by complement-based hemolysis
What happens if a recipient in blood transfusion already has preexisting antibodies to blood?
-immediate destruction of donated blood
What are immune-complexes?
-antigen-antibody complexes (important players in Type III)
In Type III hypersensitivity, what types of reactions can occur?
-systemic or localized
What conditions/diseases can Type III hypersensitivity cause?
-sequela disease
What is a sequela disease?
What is Glomerulonephritis a sequela disease from?
-disease caused by a preceding disease or injury in the same individual
-S. pyogenes
What is Glomerulonephritis?
immune complexes circulating in bloodstream are deposited on walls of glomeruli
-damage to these cells impedes blood filtration
-this results in kidney failure and death
Describe Type IV hypersensitivity.
-inflammation due to contact with certain antigens occurs after 12-24 hours
-delay reflects time it takes for macrophages and T cells to migrate to and proliferate at the site of the antigen
-ex; tuberculin response, graft rejection, allergic contact dermatitis
In the Tuberculin response, what does the skin react with?
-tuberculin (protein solution from Mycobacterium tuberculosis)
*only if exposed to tuberculosis or the vaccine!
What is a positive Tuberculin Response look like?
-red hard swelling develops
-Memory T cells secrete cytokines that attract more T cells and macrophages in a slow inflammatory response
*macrophages ingest and destroy tuberculin; back to normal
What does autoimmunity mean?
-body produces antibodies and cytotoxic T cells that target normal body cells
What are some common features of autoimmune disease?
-occur more often in older individuals
-more common in women than men
What happens in molecular mimicry?
-infectious agent has an antigenic determinant that is similar or identical to a self-antigen
-body produces autoantibodies (destroy body tissues)
What happens in Rheumatic Fever?
-antibodies generated against S pyogenes M protein cross-react with host tissues, especially heart valve tissue
What plays an important (though bad) role in immunodeficiency disease?
-opportunistic infections
What are the primary cause of immunodeficiency diseases?
-result from genetic or developmental defect in infants and young children
What is an acquired cause of immunodeficiency disease?
-direct consequence of some other recognized cause in later life
What are two causes of 'acquired cause' in immunodeficiency disease?
-severe stress; suppression of cell-mediated immunity results from an excess production of corticosteroids, which is toxic to T cells
-malnutrition and environmental factors; inhibits production of B cells and T cells
What must an individual have to be diagnosed with AIDS?
-tests positive for HIV or HIV antibodies
-low CD4 T-cell count
-one or more opportunistic infections or atypical cancers
What increases the chance of contracting AIDS?
-sexual promiscuity
-anal intercourse
-intravenous drug use
-sexual intercourse with anyone in previous categories
What are the three HIV ssRNA retroviruses?
Which is more virulent?
+HIV-1 (99% of global cases)
Where did HIV arise from?
-mutation of simian immunodeficiency virus in African chimpanzees in Cameroon
What does HIV attack in the body?
-cells displaying CD4 cell surface protein (macrophages and TH cells)
Where is HIV found?
-blood, semen, saliva, vagina secretions, breast milk
*blood and semen most effective
Describe how HIV infects CD4 cells.
-HIV gp120 interacts with macrophage CD4 protein
-this complex interacts with chemokine coreceptors
-complex forms docking site for HIV envelope-cell membrane fustion
What eventually kills the HIV host?
-loss of 70% of T-cell pool allows for opportunistic infections to kill host
In HIV, what are the chemokine coreceptors?
-CCR5 on macrophages
-CXCR4 on TH cells
What are the three main categories of Anti-HIV drugs?
-nucleoside analogs (such as AZT)
-non-nucleoside reverse transcriptase inhibitors (NNRTIs such as nevirapine)
-protease inhibitors such as saquinavir
What is the drug composition for HIV?
-a cocktail consisting of 1 protease inhibitor and 2 nucleoside analogs
HAART= highly active antiretroviral treatment
How do nucleoside analogs work?
-act as reverse transcriptase inhibitors
How do protease inhibitors work?
-inhibit HIV proteases and virus maturation

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