Chapter 14

Asthma

An atopic disease characterised by episodes of impaired breathing due to severe bronchoconstriction.

Autoantibodies

Antibodies sensitized to your own antigen.

Chemical mediators

Histamine serotonin leukotriene platelet-activating factor prostaglandins bradykinin These are produced by mast cells and basophils.

Rheumatoid arthritis

IgM and IgG bound together form the rheumatoid factor. Causes chronic inflammation. Causes swelling, pain, locking of the joints. Epstein-Barr virus may be a cause; this virus also causes mono.

Autoimmune diseases

Individuals actually develop hypersensitivity to themselves. Can be genetically linked. Can result from certain types of infections. Mostly affects women. Types: Autoantibodies, systemic, organ specific.

Allergens

Innocuous substances that induce allergy in sensitive individuals. Proteins are more allergenic than carbs, fats, or nucleic acids.

Serotonin

Its role is uncertain, but its effect seem to complement those of histamine and bradykinin.

Immunodeficiency diseases/hyposensitivies

Primary immunodeficiencies, and secondary immunodeficiencies.

Epinephrine (adrenaline)

Reverses constriction of airways and slows the release of allergic mediators. Effect is short-lived.

Xenograft

Tissue exchange between individuals of a different species. Comes from pigs. Hearts and valves come from them, because of the similar anatomy and physiology.

Decoy allergy vaccines

Used for cat allergies. This allergy shot contains an innocuous molecule that resembles a bacterium. Immune system focus/respone is redirected.

Cutaneous anaphylaxis

Wheal and flare inflammatory reaction to the local injection of allergen.

Isograft

When you transplant tissue between identical twins. Does not stimulate a rejecting response.

Systemic

affect several major ogans in the body.

Cytotoxic reactions

aka type II reactions. IgG or IgM is antibodies involved with type II reactions. These antibodies can activate complement.

Bradykinin

causes prolonged smooth muscle contraction, contraction of arterioles, increased capillary permeability, and increased mucus secretion.

Type IV hypersensitivities

is a cell-mediated immune reaction. In other words, it does not involve the participation of antibodies but is due primarily to the interaction of T cells with antigens.

Leukotriene

is the slow-reacting. Constriction of bronchioles, airway obstruction: mucus buildup. Induces gradual contraction of smooth muscle. Responsible for prolonged bronchoplasm, vascular permeability, and mucus secretion of asthmatic individual

Histamine

most profuse and fastest-acting allergic mediator. Its actions vary according to location. Constricts or dilates smooth muscle, and cause wheal and flare skin reaction and itching (pruritus).

Immunopathology

the study of disease associated with the overreactivity or underactivity of the immune response.

Allograft

Exchanges between genetically different individuals belonging to same species. Most commone type. Usually stimulate a response.

Atopic dermatitis/eczema

Intensely itchy inflammatory condition of the skin. Sensitization occurs through ingestion, inhalation, and occasionaly, skin contact with allergens.

Multiple sclerosis

Is a neuromuscular autoimmunity. Is a paralyzing neuromuscular disease associated with lesions on the myelin sheath of nerves and white matter of the nervous system. T cells and autoantibodies damage cell nerves. Can be treated with immunosuppresants and interferon beta.

Drug allergy

Is a type I allergy. Reactions range from a mild rash to fatal anaphylaxis. The drug itself is not the allergen, but haptens that are given off when the liver processes the drug.

Hay Fever

Is an atopic disease. Is a generic term for allergic rhinitis; a seasonal or year-round reaction to airborne plant pollen or molds.

Type 1 diabetes

Is an autoimmunity of the endocrine glands. Cytotoxic cell destroys cells that secrete insulin (beta cells), so sugar stays in blood instead of being processed. Is present forever.

Four categories of hypersensitivity

Type I: Allergy and anaphylaxis/Immediate hypersensitivity Type II: IgG and IgM-mediated cell damage/Antibody-mediated Type III: immune complex-mediated Type IV: Delayed sensitivity/T-cell mediated

Anaphylaxis

aka anaphylactic shock, refers to a swift reaction to allergens. Two types: Cutaneous and systemic.

Desensitization (allergy vaccines)

aka hyposensitization, is a therapeutic way to prevent reactions between allergen, IgE, and mast cells. Allergen injection stimulates production of allergen-specific IgG that can remove allergen from the system. It is hypothesized that allergen binds with IgG itself, taking it out of circulation.

Organ specific

involves only one organ or tissue.

Note

phyiological events in systemic anaphylaxis and atopy are parallel, but the concentration of chemical mediators and the strength of the response are greatly amplified.

Serum sickness

systemic response. In cases of tetanus. Allergy to horse serum, so it's called serum sickness.

Autograft

when you move tissue from one side of the body to another side of the body. Does not stimulate a rejecting response.

Antihistamines

Most widley used medications for preventing symptoms of atopic allergy. Bind to histamine receptors on target organs.

Mechanism of Type I allergy

1) Mast cells are found in all tissues but particularly in lungs, skin, GI tract, and genitourinary tract. Basophils circulate in the blood but migrate readily into tissues. 2) Each cell carries thousands of receptors that bind IgE and degranulate, releasing inflammatory cytokines.

Secondary immunodefiencies

Acquired after birth and cause by natural or artificial agents. Caused by infection (HIV), organic disease (cancers that affect bone marrow), drug therapy, radiation (all types).

Type III reactions

Aka immune complex reactions. In this type of allergy, antigens are not attached to the surface of a cell. Free floating antigen-antibody complexes escape phagocytosis and deposit in the membranes of epithelial tissues. The complement is activated and triggers inflammation. Examples: arthus reaction, serum sickness.

Allergy

An exaggerated immune response that is manisfested by inflammation.

sensitization

An immunologic state or condition that is evidenced by the acquired ability of a cell or individual to detect the presence of a foreign substance upon reexposure to the substance and to react immunologically.

Lupus

Body makes an immune response/antibodies against your own DNA. Effects are variable. Marked with muscle pain, rash, GI problems, can affect cardiac muscle when severe. Afro-Americans are more prone to this disease. Need to get immune-suppressant therapy. can't turn off just the bad immune response.

Atopy

Chronic, local allergy such as hay fever or asthma.

Arthus reaction

Caused by two vaccines injected too close together.

Sytemic anaphylaxis

Characterized by sudden respiratory and circulatory disruption that can be fatal within minutes due to airway blockage. Result of sudden, massive release of chemicals into the tissues and blood which act rapidly on target organs. Route of entry of allergen vary, but bee stings and injection of antibiotics or serum are most commonly implicated.

Rh compatibility

If mom is Rh negative, and carries a Rh positive, could be problematic. If baby rbc gets into mom's blood, Rh + against Rh -, her body will respond with IgG. IgG will cross the placenta and destroy the baby's rbc.

Type I Allergic reactions

IgE-mediated; involves mast cells, basophils, and allergic mediators. Includes allergy and allergens. Two levels of severity: Atopy and Anaphylaxis

Food allergy

Most common food allergies come from peanuts, fish, milk, eggs, shellfish, and soybeans. Symptoms include vomiting, diarrhea, abdominal pain, potentially hives, rhinitis, asthma, and anaphylaxis.

Contact dermatitis

Most common reaction. Allergy to poison ivy, poison oak, haptens, drugs. Requires a sensitizing dose followed by a provocative dose. Allergen penetrates skin, and cause response from T cells, lymphocytes and macrophages. They release enzymes and cytokines that damage the epidermis and vicinity.

Symtpoms of multiple sclerosis

Muscle weakness, tremors, difficulties in speech and vision, paralysis.

Hypersensitivity

Overreactivity of the immune system that takes forms of allergy and autoimmunity. The tissues are innocent bystanders attacked by immunologic functions that can't distinguish one's own tissues from those expressing foreign material.

Prostraglandins

Powerful inflammatory agents. Responsible for vasodilation, dilated blood vessels, increased pain sensitivity (nerve), and constriction of bronchioles.

Organ transplantation

Rejection of tissue is due to cytotoxic T cells. Classes of grafts: Autograft, Isograft, allograft, Xenograft.

Anaphylaxis

Systemic, sometimes fatal reaction that involves airway obstruction and circulatory collapse.

Infectious allergy

TB Test. Acute skin inflammation at the infection site following an extract of m. tuberculosis. Helper T cells release cytokines and recruit inflammatory cells such as neutrophils, macrophages, and eosinophils.

Hyposensitivity or immunodeficiency

The immune system is incompletely developed, suppresed, or destroy

Primary Immunodeficiencies

You are born with. Inherited abnormality. Lymphocytes are absent, present at a low level, or don't function normally. Absences of T or B cells or both.