Immunodeficiency, Autoimmune diseases, and hypersensitivities Flashcards
primary immunodeficiency
- congenital immunodeficiency
- inborn error that affects 1 or more immune factors and leads to deficient immunity
- rare
secondary immunodeficiency
- acquired immunodeficiency
- more common
- patient starts out with a normal immune system and then experiences a decline in immune system rigor
causes of secondary immunodeficiencies
- age
- certain infectious agents
- medical interventions
- systemic disorders
aging
- associated with increased susceptibility to infections
- associated with worse prognosis following infection and a longer recovery time
- aging is associated with reduced response to vaccination
inflammaging
balance between anti-inflammatory and pro-inflammatory becomes unbalanced, favoriting pro-inflammatory
immune senescence
- occurs during aging
- immune stimulation at the basal level leads to failure to respond to acute stimuli
- decline of output from the bone marrow of some cells
- function of cells declines
- causes decline of memory cells
immunodeficiencies caused by infectious agents
- many pathogens have virulence factors that directly inhibit host immune defenses
- some break down antibodies, interfere with cellular signaling, or directly infect immune system cells
how does HIV destroy the immune system?
- infects and kills CD4 T helper cells
- causes a decrease in the cell mediated and humoral branches of adaptive immunity
what are the consequences from HIV of destruction of immune function
- AIDS
- increased susceptibility to opportunistic function
secondary immune deficiencies: nutrition
- metabolism and nutrition are closely linked
- starvation and malnutrition can suppress immune function and increase susceptibility to infections
- obesity is associated with aberrant immune activity
- increasing risk for associated inflammatory diseases
- balanced nutritional and metabolic homeostasis are crucial for appropriate immune function
what can lack of self tolerance lead to
autoimmune disorders
rheumatoid arthritis
cartilage destruction, bone erosions, inflammation, impaired joint function, and pain
dermatomyositis
- endothelial cell swelling and necrosis, vessel wall membrane attack complex deposition, and myocyte-specific MHC-1 up-regulation
- cell mediated and innate immune system dysfunction
interstitial bladder cystitis/ mastocytosis
elevated levels of mast cell mediators in the urine such as interleukin and histamine cause vasodilation, bladder mucosa damage, inflammatory cell inflitrate
systemic lupus erythematosus
global loss of self-tolerance, overactive T and B cells, joint, skin, kidneys, blood cells, brain, heart and lungs
steps of systemic lupus erythematosus
- production of autoantibody
- immune complex formation between circulating DNA and antibodies to DNA
- presentation of autoantigen to T cells
- inflammatory cytokine production
Type 1 diabetes implicated infectious agent
coxsackievirus B
guillian-barre syndrome implicated infectious agent
campylobacter jejuni
rheumatic heart disease implicated infectious agent
streptococcus pyogenes
multiple sclerosis implicated infectious agent
over 20 have been identified
- mainly herpesvirus 6 and epstein-barr virus
are there cures or preventions for autoimmune disorders
NO
hypersensitivity
an inappropriate immune response
Type 1 hypersensitivity
- Allergies
- driven by IgE
- NOT associated with autoimmunity
- ex. atopic asthma and atopic dermatitis
development of Type 1 hypersenstivities
- sensitization stage: allergens trigger IgE production, IgE binds to the surface of mast cells
- post-sensitization exposure: a person is exposed to the allergen after sensitization, the allergen binds to IgE on mast cell, which triggers degranulation
Type II hypersenstivities
- cytotoxic
- driven by IgG or IgM interacting with antigens on cell surfaces or extracellular antigens
- associated with autoimmunity
erythroblastosis fetalis (Type II hypersensitivity)
- the mother has Rh- blood and the fetus has Rh+ blood, during labor, the fetal Rh+ blood with enter the mothers system, and she will develop anti-Rh antibodies
- This is only a problem if the mother becomes pregnant with another Rh+ baby, the mother anti-Rh antibodies will attack the fetus, leads to hemolytic disease of the newborn (HDN)
Type III Hypersensitivities
- Immune complex
- driven by IgG or IgM interacting with soluble antigens
- associated with autoimmunity
Type IV Hypersensitivities
- Delayed hypersenstivity
- driven by T cells interacting with soluble or cell- or matrix- bound antigens
- associated with autoimmunity
