Microbiology chapter 40

a person with type B blood contains antibody

A

a person with type O blood has antibody

A and B

symptoms include sneezing, wheezing, itching, and coughing, water eyes, nasal congestion, runny nose, and sinus headache. it is caused by pollen, dust, animal hair and dander, another environmental substances, release of mediators such as histamine

Allergic Rhinitis (hay fever)

a delayed type of hypersensitivity that affects the skin. This reaction is initiated by an allergen called a contact sensitizer that contacts the skin and sensitizes the immune system by generating T cells.

Allergic contact dermatitits (ACD) or contact sensitivity

Hypersensitivity type I reactions-immediate IgE-mediated

Allergic rhinitis, allergic asthma, allergic conjunctivitis, atopic dermatitis, urticaria, and food allergies

the formation of immune complexes at the site where the intradermal injection of the antigen combined with its preformed antibodies

Arthus Reaction

a common chronic inflammatory skin disease in childhood that is characterized by intense pruritis and cutaneous inflammation. Up to 50% of children go on to develop asthma. The pathogenesis involves genetic factors, skin barrier defects and immune dysregulation

Atopic Dermatitis

a person with type A blood contains antibody

B

coined the term "anaphylaxis" to characterize these reactions which are "against protection"

Charles Richet

include host cell material such as DNA which play a pivotal role in causing the disease systemic lupus erythematosus (SLE) commonly called Lupus.

Endogenous antigens

an occupational disease that occurs in certain sensitive individuals who have been exposed to moldy, rotting hay. The disease is characterized by a type of pneumonitis and results from type III immune complexes localizing in the respiratory tract mucosa

Farmer's lung

mast cells express high affinity for these receptors referred to as Fc epsilon RI (FceRI or CD23). the binding is irreversible. they also bind IgE antibodies that are not bound to antigen molecules

Fc receptor

occurs when a pregnant mother who is Rh- produces antibodies against her child's red blood cells because they are Rh+

Hemolytic disease of the newborn (HNDB) or erythroblastosis fetalis

antibodes in the serum (i.e., A, B, AB, and O) are of which Ig class

IgM

types of mast cells involved in type I hypersensitivity reactions

Mucosal mast cells (MMC) and connective tissue Mast cells (CTMC)

IgE bound to mast cells and basophils. Triggers degranulation and release of pharmacological active mediators examples include hay fever, asthma

Type I (anaphylatic reactions)

this type of hypersensitivity reaction is also referred to as immediate hypersensitivity because its manifestations occur with in seconds or minutes after a sensitized immune system is re-exposed to a foreign substance. examples include allergic rhinitis, allergic asthma, anaphylactic shock, and acute drug allergic reactions

Type I (anaphylaxis)

this type of hypersensitivity reaction occur when IgM or IgG antibodies bind to antigens on the membrane of cells and initiate the complement cascade which causes damage or destruction by several cytotoxic mechanisms. examples include: transfusion incompatibility and Rh incompatibility

Type II (Cytotoxic reactions)

Ig and complement lyse cells examples include transfusion incompatibility and Rh incompatibility

Type II (cytotoxic reactions)

immune complex deposition and complement activation mediate tissue destruction examples include arthus reaction serum sickness

Type III (immune complex)

this type of hypersensitivity reaction is initiated when antigens-antibody complexes are formed, accumulate, circulate, and then become trapped in tissues where they are activate the complement cascade. examples include arihus reaction, serum sickness

Type III (immune complex)

this type of hypersensitivity reaction is also referred to as cell-mediated hypersensitivity, are caused by cells and not antibodies. it has a delayed onset of about one to two days after initiation and hence the term delayed type hypersensitivity (DTH)

Type IV (cell mediated or delayed-type)

activated T lymphocytes triggers cell-mediated immune response examples include tuberculin reaction and contact dermatitis

Type IV (delayed)

known a delayed type hypersensitivity (DTH) because of the time period (24 - 72 h) it takes for the inflammatory reactions to occur

Type IV hypersensitivity

foreign substance that can provoke an allergic response is also referred to as

allergen

Binding of antibodies to target cells can also cause cell destruction by a process called

antibody dependent cell-mediated cytotoxicity (ADCC)

in type III hypersensitivity the antibody encounters and binds to its specific antigen and immune complex precipitate is formed that is referred to as

antigen-antibody (Ag-Ab) complex

mediator found in Mast cells: newly synthesized mediators

arachidonic acid; leukotrienes, prostaglandins, and thomboxanes

clinical manifestations of hypersensitive type III reactions

arthus reaction, serum sickness, farmer's lung

the activation phase in type I hypersensitivity involves

binding of allergen to IgE molecules on Mast Cells/Basophils, Cross-linking initiates degranulation of mast cells, how much of granule content is released during degranulation, and recovery of granules after degranulation

mediators found in Mast cells- primary (preformed) mediators

clinical manifestation of histamine, proteases, and TNF

hypersensitive III reactions caused by immune complexes

complement-mediated damage, thrombosis, and hemorrhaging

Cell destruction results from the activation of the complement system which produces components that create pores in the cell membrane and eventually lyses the cell

complement-mediated lysis

the effector phase in type I hypersensitivity involves

degranulation in the lungs, degranulation in blood vessels, and degranulation in the gastrointestinal tract

this hypersensitivity reaction take a slower time to develop about 24-72 hours

delayed hypersensitivity reaction

include microorganisms such as bacteria and viruses and material that can be injected into the recipient such as vaccine preparations

exogenous antigens

two types of antigen that can trigger the formation of immune complexes in type III hypersensitivity

exogenous antigens and endogenous antigens

when the immune system has enhanced or heightened (hyper) reactions or sensitivity to these substances which can produce damaging, destructive, and even fatal consequences and encompasses an altered state of immune response to foreign material

hypersensitivity or allergy

Types mediated by the production and action of antibodies

hypersensitivity reactions types I, II, and III

types mediated by a T cell response

hypersensitivity reactions types IV

two classes of hypersensitivity reaction

immediate hypersensitivity and delayed hypersensitivity

this hypersensitivity reaction occurs rapidly usually within minutes but less than 24 hours

immediate hypersensitivity reaction

this response of type I hypersensitivity reactions is initiated by the allergen being re-exposed to a sensitized system which results in mast cell activation and degranulation

immediate reaction

responses of type I hypersensitivity reactions

immediate reaction and late-phase reaction

this response of type I hypersensitivity reactions occurs about 8 hours but within 48 hours after the immediate response, is characterized by more exaggerated swelling and other manifestations of inflammation depending on the location of the mast cells and basophils

late-phase reaction

other factors other than allergens that can activate mast cells

lectins, strawberries, complement components such as C3a ad C5a, temperature and pressure, drugs such as codeine and morphine

a clinical manifestations of Type I hypersensitivity that is confined to a particular tissue or organ. Once the mast cell and basophils in these sites are triggered to degranulate, the released chemicals provoke the allergic symptoms in this region of the body. Examples include hay fever and asthma

localized anaphylaxis

clinical manifestations of Type I hypersensitivity include

localized anaphylaxis or systemic anaphylaxis

In this hypersensitive type III reactions the antigen-antibody complexes are formed at the particular localized site where the antigen is introduced.

localized type III reaction

cells involved in Type I hypersensitivity reactions

mast cells and basophils

a person with type AB blood contains antibody

none

This process of rendering cells susceptible to phagocytosis is referred to as

opsonization

common allergens involved in type I hypersensitivity

plant pollen, mold spores, animal hair and dander, dust mites, insect venom, and certain protein, foods, and drugs

a classic example of DTH affecting the skin. The leaves of the poison ivy plant secrete an oil that contains chemicals called catechols, specifically pentadecatechol. Once these chemicals contact and penetrate the outer layers of the skin, they begin the phase of sensitization.

poison ivy dermatitis

clinical manifestation of type IV reactions include

redness (erythema), formation of a hard bump (induration)

believed to be a type IV hypersensitive reaction however, the specific cause of the disease is not known. The disease is granulomatous in nature and can affect multiple organs but primarily the lungs. It usually occurs around 30 to 40 years of age and is clinically manifested as alveolitis and granulomas surrounded by monocytes and

sarcoidosis

The sensitization phase in type I hypersensitivity involves

sensitization of allergens and passive sensitization

triggering the type I hypersensitivity reactions involve 3 phases

sensitization phase, activation phase, and effector phase

mechanism of type IV hypersensitivity include

sensitization stage and elicitation stage

a clinical manifestations of Type I hypersensitivity is the classical anaphylaxis that was observed by Portier and Richet. the entire body of the individual is involved in the allergic response which is sudden and severe, and can be life threatening.

systemic anaphylaxis

In this type III hypersensitive reactions, Ag-Ab immune complexes are formed in the circulation where they are transported throughout the body and then deposited in various tissues and organs where they subsequently cause inflammatory reaction and tissue damage.

systemic type III reaction

In type III hypersensitive reactions, Sites Where Immune Complexes are Deposited

the kidneys, small blood vessels, skin, joints, and heart

commonly know as hives, is an inflammatory skin rash usually caused by allergic reactions

urticaria