Immune Disorders

7/18/2019 Immune Disorders

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Disorders of the ImmuneSystem



Disorders of Immune System

• Defenses against infection

• Immune system disorders

– Autoimmune diseases

– Immunodeficiency



Defenses Against Infection

• Barriers (non-specific)

– Skin

– Mechanical removal (coughing, vomiting,

diarrhea, skin sloughing)

– ormal flora

– Antimicro!ial secretions

• Inflammation (non-specific)

• Immunity (specific)



Immune Response

• atural vs" Ac#uired

• Active vs" $assive

• $rimary vs" Secondary

• %umoral vs" &ell-Mediated



Humoral Immunity

• B 'ymphocytes ($lasma &ells)

– $roduced in !one marro

– Make anti!odies (immunoglo!ulins)



Antibodies

• $rotein molecules produced !y B-cells

• Specific shapes allo !inding to specific

molecules (antigens)• Allo !ody to respond defensively to

presence of specific potential threats



Antibody Types

• Ig

• IgM

•IgA

• IgD

• Ig*



IgG

• Most common anti!ody type

• +nly anti!ody that crosses placenta

•

$rime mediator of secondary immuneresponse

• $rincipal defender against !acteria,

viruses, and toins



IgM

• Macroglo!ulin

• &onfined to !loodstream

•

irst anti!ody to appear in response topresence of antigen

• Agent of primary immune response



IgA

• Secretory anti!ody

• ound in saliva, tears, respiratory

secretions, I tract secretions

• rontline !acterial, viral defense



IgD

• .ole not fully understood

• 'o serum levels

•

%igh concentrations on B-cells• May act as receptors that trigger

production of other anti!odies



IgE

• /ery lo serum levels

• $rimarily !ound to mast cells in tissues

•

&ontrols allergic response• $revents parasitic infections



Antigen-antibody binding initiates

reactions that• eutrali0e !acterial toins

• eutrali0e viruses

• $romote phagocytosis

• Activate components of inflammatory

response



!ell-Mediated Immunity

• 1 'ymphocytes

– +riginate in !one marro

– Altered !y passage through thymus

– .esponsi!le for mediation of cellular

immunity



T "ymphocyte Types

• %elper cells (12 cells)

• &ytotoic cells (3iller 1 cells)

• Suppressor cells• Memory cells



Helper T-!ells

• Master 4on-sitch5 of immune system

• .ecogni0e antigens

• Secrete lymphokines that activate allother immune system cells

• Stimulate B-cells to !egin anti!ody

production



!ytoto#ic $%iller& T-!ells

• .espond to presence of antigens and

lymphokines produced !y 1-2 cells

•

Seek out, !ind to, and destroy6 – &ells infected !y viruses

– Some tumor cells

– &ells of tissue transplants

• &an deliver lethal hits on multiple cells in

se#uence



Suppressor T-!ells

• $roduce lymphokines that inhi!it

proliferation of B and 1 cells

•

Donregulate or dampen immuneresponse



Memory T-!ells

• %ave previously encountered

specific antigens

•

.espond in enhanced fashion onsu!se#uent eposures

• Induce secondary immune response



Inflammation

• +ccurs in vasculari0ed tissue

• onspecific response to in7ury

•

.esponse is same regardless of agent thatinitiates it



Inflammation 'hysiology

• 1riggered !y cellular in7ury

• In7ury activates mast cells

•

Mast cells release chemical mediators6 – %istamine

– %eparin

–

'eukotrienes (S.S-A) – *osinophil chemotactic factor





Inflammation 'urposes

• &onfines in7urious agents

• Increases !lood cell, plasma

movement to in7ured areas• *nhances immune response

• Destroys in7urious agents

• $romotes healing



Inflammation !ellular

!omponents• eutrophils

– $hagocytic cells

– *ngulf foreign material9organisms

– Arrive early

– Short-lived




!omponents• Macrophages

– $hagocytic cells

– *ngulf foreign material9organisms

– Arrive later

– 'ong-lived

– 1ransfer antigens !ack to 12 cells

– %elp initiate immune response to specific

agents




!omponents

• *osinophils

–

Secrete caustic proteins – Dissolve surface mem!ranes of parasites



Disorders of Immunity



Autoimmune Disease

• &linical disorder produced !y an

immune response to a normal tissue

component of a patient:s !ody



Autoimmune Diseases

• %yperthyroidism

• $rimary myedema

• 1ype I dia!etes• Addison:s disease

• Multiple sclerosis

• Myasthenia gravis



Autoimmune Diseases

• .heumatic fever

• &rohn:s disease

•

;lcerative colitis• .heumatoid arthritis

• Systemic lupus erythematosis



Systemic "upus Erythematosis

• $rimarily occurs in <=- to 2=-year old females

• Also in children and older adults

• >=? of patients are female

• Autoimmune reaction to host DA

• Mortality after diagnosis averages @? per year




• Signs9Symptoms – acial rash9skin rash

triggered !y sunlight

eposure

– +ral9nasopharyngeal ulcers

– ever

–

Arthritis




• Signs9Symptoms

– Serositis (pleurisy, pericarditis)

–

.enal in7ury9failure – &S involvement ith

sei0ures9psychosis

– $eripheral vasculitis9gangrene

– %emolytic anemia




• &hronic management

– Anti-inflammatory drugs

•

Aspirin• I!uprofen

• &orticosteroids

– Avoidance of emotional stress,

physical fatigue, ecessive sun

eposure



Disorders of Immunity

Immunodeficiency Diseases




• &ongenital

• Ac#uired




!ongenital• B cell deficiency

– Agammaglo!ulinemia

– %ypogammaglo!ulinemia




!ongenital• 1 cell deficiency

• IgA deficiency

• Severe com!ined immune deficiency

syndrome (B and 1 cell deficiency)




Ac(uired• utritional deficiency

• Iatrogenic (drugs, radiation)

• 1rauma (prolonged hypoperfusion)

• Stress

•

Infection (AIDS)

Documents

Immune Disorders