Alterations in Immune Function

innate immunity

bloodbourne and physical barriers

physical barriers

skin
mucous membranes
saliva
urine & tears
stomach acid

what do physical barriers do in innate immunity?

stops infection before it enters the body

T-cell immunity other term

cell-mediated immunity

B-cell immunity other term

humoral immunity

what are specific immune system mechanisms capable of

recognizing foreign invaders
destroying foreign invaders
retaining memory of the encounter

other words for specific immunity

acquired, adaptive

is specific immunity active or passive

active

what does adaptive immunity do?

confers a protected state attributable to body's immune response as a result of active infection/inflammation

what does the development of active immunity require?

the maturation & maintenance of memory B cells

passive adaptive immunity

transfer of plasma containing performed antibodies against specific antigen from a protected

pediatric considerations for adaptive immunity

infants have immature immune system
rely on maternal antibodies for protecting until they're own is mature
maternal IgG passed down through placenta & breast milk

geriatric considerations for adaptive immunity

Immune system has decreased ability to respond to antigenic stimulation
Can respond to infection w/memory T/B cells, but less able to react to new antigens
IgG production decreases
increased autoimmune disease risk

T helper cells

secrete cytokines

clonal expansion

B cell divides through T helper cell assistance, antigen binding

cytotoxic cells

CD8+
destroy target cells

regulatory T lymphocytes

suppress other immune cells

B lymphocytes

secrete antibodies, antibodies produced by B cells

IgG

most prevalent antibody (75%)

IgM

first produced on antigen exposure

IgA

found in body secretions

IgD

present on B-cell membrane, signal transduction

IgE

binds to basophil & mast cell membranes, mediates inflammation and allergy

active immunity

individuals exposed to antigen that stims their own lymphocytes to produce memory cells
Long-term protection, can take several weeks to develop

passive immunity

an impermanent form of acquired immunity in which antibodies against a disease are acquired naturally or artificially
immediate, but temp protection

example of passive immunity

placenta, transfer of antibodies

examples of active immunity

response to vaccine
response to disease
transplant rejection

immune system

defends body against infection by antigens
patrols for and destroys abnormal or damaged cells

excessive immune responses

altered immune response to an antigen
excessive immune response resulting in tissue damage or abnormal cell function

autoimmunity

immune system attacks own tissues; produces autoimmune disease or hypersensitivity reactions
polygenic and multifactorial

allergy

hypersensitivity to environmental (exogenous) antigens

alloimmunity

immune response to tissues of another person (transplantation)

antigenic mimicry

antigen that invades, mimics self to look like a person's cells
body doesn't react so it does damage

sequestered antigens

self antigens are isolated from the immune system within an organ during the neonatal period
occur in sites such as the cornea of the eye, the testicles, brain, or other areas not drained by lymphatics.
If and when these sites are damaged later in life, the hidden or sequestered proteins are exposed to the immune system, which does not recognize them as self; therefore the damaged cells are attacked

abnormal production of subclasses of T lymphocytes

autoimmunity
no cells = problem

development of abnormal B cells that don't respond to suppressor T-cell signals

no B cells communicating = no protection

genetic factors

female gender
MHC genes

MHC genes

major histocompatibility complex genes
human leukocyte antigen complex
cluster of genes on chromosome 6

MHC class I

Produced on endoplasmic reticulum, combined w/peptide fragments in cytoplasm (degradation of normal intracellular proteins)
Cycled to cell surface for inspection by T cells, if abnormal proteins produced, immune response will occur
Viral protein is a source of forgien antigen

MHC class II

T helper cells recognize foreign antigens bound, but only if physically bound to MHC II protein
Present antigens obtained from extracellular sources
Antigens engulfed by antigen-presenting cells

MHC class III

code for various proteins, important to inflammatory reactions (complement proteins)

environmental triggers

chronic or mult or viral bacterial infections
noninfectious environmental factors (autoimmunity)
environmental & occupational stress
autoantibodies injure body tissues through mechanisms of type II & type III hypersensitivity reactions

immunosuppressive therapy

corticosteroids, biological agents, immunomodulators, cytotoxins

purine analogs

inhibit the synthesis of DNA and are used in multiple autoimmune diseases

therapeutic plasmapheresis

analogous to dialysis and involves the selective filtering or removal of plasma or a plasma cell type as well as protein-bound toxic substances.

intravenous immunoglobulin

used to help with disorders
can neutralize a wide range of antigens
the further mechanism of activity may include decreased T-cell proliferation, reduced complement activation, and other possible pathways

hypersensitivity

normal immune response that is either inappropriately triggered, excessive, or produces undesirable effects on the body
specific to a particular antigen

type I hypersensitivity

IgE medicated
immediate allergic or anaphylactic
mast cell degranulation

mast cell degranulation

histamine, kinin, prostaglandins, interleukins, leukotrienes
increased vascular permeability, vasodilation, hypotension, urticaria, bronchoconstriction

type I hypersensitivity examples

seasonal & food allergies
bee stings
atopic dermatitis

type I clinical manifestations

hives (urticaria)
season allergic rhinitis
eczema
mild bronchoconstriction
angioedema (tightening of throat, localized edema, wheezing, tachycardia)
anaphylaxis (bee stings, seafood, peanut)

anaphylactic reaction causes

insect stings (bee, wasp, ant), medication reaction , food allergy

anaphylactic reaction symptoms

rapid onset
dyspnea (tight throat, laryngeal edema, bronchospasm)
feelings of apprehension
tingling/swelling in mouth, face, throat, tongue
itching
decreased BP
tachycardia
loss of consciousness (LOC)

type II hypersensitivity

tissue macrophages
IgG IgM
immediate

alloimmunity

the immune system reacts against antigens on tissues from other members of the same species

autoimmunity

production of antibodies against the tissues of your own body

type IIa

transfusion reaction (alloi)
hemolytic disease of newborn (alloi)
myasthenia gravis (auto)
hyperacute graft reaction (alloi)

type IIb

grave's disease (auto)

describe type II blood transfusion reaction

a person has type A blood and anti-B antibodies
there is a blood transfusion with type B blood
antibodies bind with with the type B blood
1 way: binding by macrophage followed by cell phagocytosis (eaten)
other way: complement activation followed by cell lysis

myasthenia gravis

a chronic progressive disease characterized by chronic fatigue and muscular weakness
limited receptors available for AcH impairs neuromuscular transmission

transfusion reaction

reaction of the body to a transfusion of blood that is not compatible with its own blood
type II
surface antigens + opposing antibodies --> agglutination (clumping) and hemolysis (cells break)

transfusion reaction allergic symptoms

flushing, hives/rash, increase anxiety, wheezing dippnea, decreased blood pressure, puritis, shortness of breath

transfusion reaction labs and treatment

CBC (complete blood count)
Bilirubin
Fluids
Symptom management

transfusion reaction febrile symptoms

fever, chills, tachycardia, headache, anxiety, tachypnea, flushing

transfusion reaction hemolytic symptoms

hemogloblinuria, chest pain, apprehension, low back pain, chills, fever, tachycardia, decreased BP, inc resp rate, inc anxiety, hypotension, tachypnea

hemolytic disease of the newborn

Rh negative mother & Rh pos father
mother has Rh pos baby
bay's blood cells enter mother's bloodstream during delivery, invading Rh pos cells cause the production of Rh antibodies
in a later pregnancy, Rh antibodies attack baby's blood cells, causing Rh disease (fatal)

type III hypersensitivity

immune complex mediated
antigen-antibody complexes deposited in tissue, result in activation of complement and subsequent tissue inflammation & destrution
neutrophils
IgG IgM
immediate

type III hypersensitivity examples

tissue deposition, immune complex glomerulonephritis, systemic lupus erythematosus

systemic lupus erythematosus SLE

chronic multisystem inflammatory disease
autoantibodies against: nucleic acids, erythrocytes, coagulation proteins, phospholipids, lymphocytes, platelets
circulating immune complexes containing antibody against host DNA are deposited in organs

SLE treatment

NSAIDs
corticosteroids for serious disease
immunosuppressant drugs
protection from sun exposure
IVIg

SLE symptoms

tachypnea, cough, pleural inflammation/effusion
butterfly rash over cheeks & nose, erythematous rash to areas exposed to sunlight
weight loss
fatigue
fever inc infection
arthritis
depression
hematologic and neurologic disorders
raynaud's (finger and toes turn purple)
pericarditis
vascular inflammation
lupus nephritis
proteinuria
hematuria

type IV hypersensitivity

cell mediated
tissue destruction caused by toxins from CD8 T cells
Th (helper) cells produce cytokines that recruit phagocytes (lymphocytes and macrophages)
no antibody
delayed

graft rejection

organ transplantation MHC/HLA matching
organ should come from another family member bc you don't want rejection

hyperacute transplant rejection

immediate and rare
preexisting antibody to the antigens of the graft

acute transplant rejection

cell-mediated immune response against unmatched HLA antigens

chronic transplant rejection

months or years
inflammatory damage to endothelial cells of vessels as a result of a weak cell-mediated reaction against minor HLA antigens

which hypersensitivity types involve activation of complement?

types II and III

all hypersensitivities EXCEPT this one involve antibodies

type IV

which hypersensitivities involve cell membrane antigens?

types II and IV

all hypersensitivities EXCEPT this one may be autoimmune

type I

these hypersensitivities may involve foreign antigens

types I,II,III,IV

what hypersensitivity type is graft-versus-host disease?

type IV (delayed) reaction

the antibody type IgE is involved with which type of hypersensitivity reaction?

type I (anaphylactic) reaction

antibodies are the mediators of all of the hypersensitivity reactions except?

type IV (delayed) reaction

the first type of antibody to be secreted on initial exposure to an antigen is

IgM

rheumatoid arthritis hypersensitivity type

type III, autoimmune

asthma hypersensitivity type

type I, NOT autoimmune

graves disease hypersensitivity type

type IIb, autoimmune

hemolytic disease of the newborn hypersensitivity type

type II, NOT auto

contact dermatitis

type IV, NOT auto

post-streptococcal glomerulonephritis

type III, NOT auto

type I DM hypersensitivity type

type II, autoimmune

systematic lupus erythematous

type III, autoimmune

allergic rhinitis hypersensitivity type

type I, NOT auto

myasthenia gravis hypersensitivity type

type II, autoimmune

deficient immune responses

result from functional decrease in one or more components of immune system
failure of immune response --> inc susceptibility to infections

primary deficient immune response

congenital, genetic, acquired defects
predisposed to multiple deficiencies
development of unusual/recurrent severe infections

secondary deficient immune response

non-immune system disorders (cancer, pregnancy, drugs, infection, aging)
treatments that secondarily affect immune function
more common than primary
come from problems in neuroendocrine and immune system interactions
environmental or psychologic stress
neuroendocrine response to stress with increased corticosteroid production inc risk of infection

severe combined immunodeficiency

a congenital disease affecting T cells that can result from a mutation in any one of several different genes
infants can easily die from this

DiGeorge syndrome

t-cell disorder, poor development of body systems, heart defects