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LEUKOCYTE/ IMMUNE SYSTEM DISORDERS. VARIATIONS IN IMMUNE FUNCTION. Fetal and Neonatal Immune Function Antibody, phagocytic and complement functions deficient at birth. Maternal antibodies are protective 5- 6 months Immune Function in Elderly Diminished T cell and antibody response
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VARIATIONS IN IMMUNE FUNCTION • Fetal and Neonatal Immune Function • Antibody, phagocytic and complement functions deficient at birth. • Maternal antibodies are protective 5- 6 months • Immune Function in Elderly • Diminished T cell and antibody response • Increased auto antibodies
Factors Affecting System • Stress • Nutrition • Drugs • Other diseases • renal failure • malignancy • diabetes mellitus • systemic infections
HYPERSENSITIVITY DISORDERS • Type I Immediate—IgE mediated • Type II Sub-Acute—IgG or IgM • Type III Sub-Acute—IgG or IgM • Type IV—Delayed –T Cell mediated
Type I Hypersensitivity • Allergies, anaphylaxis, anaphylactic shock • anaphylactoid reactions • Occurs in seconds to minutes • IgE normally binds to surface of basophils and mast cells • Concentrates in lining of respiratory and GI tracts, skin
Type I Hypersensitivity • Offending antigen enters body—ingestion, injection, inhalation • Peanuts, walnuts, latex • Any insect venom (bee stings) • When appropriate antigen binds to 2 IgE molecules, they cross link • Histamine, leukotrienes, interleukins, kinins released
Type I Hypersensitivity • Get contraction smooth muscle, increased permeability of vessel walls • Fluid leaks into interstitial space, smooth muscle in respiratory and GI tracts spasms • Angioedema, esp of face, hands, feet • Vessels not damaged • If this is local, irritating but not likely to be fatal
Signs of Anaphylaxis begin within seconds to minutes • Body wide reaction to ingested, inhaled, injected ag • Acute systemic reaction due to IgE release • Urticaria • Itching, laryngeal edema, angioedema • Bronchospasm—may die from anoxia • Hypotension—may die from hypotensive shock • GI and UG cramping (least common) • Administer epinephrine, establish airway, give antihistamines and glucocorticoids
Atopy-chronic, inherited disorder • IgE at mucosal surfaces reacts with normally innocuous compounds • Pollen, animal dander, certain types of foods • Reaction is localized to surface stimulated • Multiple manifestations • Associated with increased incidence of allergic rhinitis and asthma
Atopic eczema (atopic dermatitis) • Associated with allergic rhinitis or asthma • T helper 2 cells overproduce IL 31 (believed to be underlying problem) • Weeping, eroded, red, scaly patches of skin • scalp, face, and diaper area most often affected • exacerbated by weather changes, drying from XS soap and water • severe itching2º bacterial infection
Atopic eczema (atopic dermatitis) • May spontaneously disappear as child ages • Other allergies commonly appear • Areas of knee, elbow, neck, etc. involved if continues • Points of flexion/extension • May spread over entire body in adults—remission rare • Treat with dietary restrictions (infants), moisturizers, antihistamines • Antibiotics for skin infections • Topical steroids/T cell modulators as needed
Allergic rhinitis—nasal allergy • Seen more in developed nations with high standards of cleanliness • less exposure to pathogens and more exposure to chronic irritants • Less development of the suppressor (regulatory)) T cells • May predispose person to developing asthma
Allergic Rhinitis--S&S • Stuffy, runny nose; red, weepy eyes; itching of eyes and nose • Dark circles under eyes, chronic sinusitis may develop • May report ringing in ears or sensation of pressure in ear • Eosinophils in nasal secretion distinguishes from infection
Subsets of allergies • Seasonal form (hay fever)—pollen, mold • Perennial allergies—more likely dust mites, animal dander
Cytotoxic (Type II) and Immune Complex (Type III) Diseases • Type II involves antibodies binding cells—tissue specific reaction—rapid • Type III involves antibodies binding soluble proteins—serum sickness • Develops 7-10 days after antigen is introduced • Urticaria, angioedema, fever, generalized lymphadenopathy • Activation of complement as complexes precipitate in capillaries • Joint pain, renal dysfunction, GI problems
Type IV Hypersensitivity—48-72 hours • Allergic Contact Eczema—delayed hypersensitivity T lymphocytes • Poison ivy, nickel allergies • Weeping, red, puritic vesicles at site of contact • Localized edema initially, thickening of skin if contact continues • avoid offender, steroids as needed
Type IV • Fig 8-6
AUTOIMMUNE DISORDERS #3 cause of death in the US
AI Disorders -- general • Immune system must tolerate normal antigens by removing all T and B cells that would react with self proteins • AI diseases occur when the immune system starts to attack the cell of the body—break in tolerance • Occur more frequently in females than males • Precise cause unknown—believe that foreign antigen resembles a self antigen • Several are associated with HLA antigens--see T 8-5 • Presence of one increases risk of others • Relapse and remission common • Seem to get worse when stressed
Immune system removes foreign compound first • Continued surveillance sees normal cell proteins presented by MHC I molecules as foreign, and attacks those cells • System eventually turns on to normal proteins • Some suggestion that may start if inflammation accompanies apoptosis reaction • AI diseases be cytotoxic T cell mediated or antigen-antibody reaction or both
Organ specific AI diseases Damage is limited to one organ/tissue Rest of the body suffers as a result of damage done to that organ/tissue
Examples • Idiopathic thrombocytopenic purpura • Autoimmune hemolytic anemia • Type I Diabetes Mellitus • Autoimmune thyroiditis • Addison’s Disease • Celiac Disease
Multiple organ system AI diseases Most of these involve antibodies that react with the body’s connective tissue
Examples • Rheumatoid arthritis • Systemic Lupus Erythematosis (SLE) • Scleroderma
Rheumatoid arthritis • In women 2.5X as often as in men, peak incidence 40-60 years; 1% all adults • Seems to have some association with HLA-DR4 (Minor HC) antigens (varies with ethnic group) • Production of multiple destructive enzymes: collagenase, protease • Attacks synovial membranes • Produces granulation tissue that extends into joints-pannus • Destruction of cartilage, ligaments, tendons, bones
Signs & Symptoms • Fever, fatigue, malaise • Swollen, painful joints; often bilateral • Hands, knees, feet • Morning stiffness that lasts > 1 hour • Deformed joints as cartilage is destroyed
Juvenile rheumatoid arthritis • Systemic onset—boys and girls equally—20% • poorest prognosis • Multiple organs, any age • Polyarticular onset—girls 2X as often as boys—40% • 5 or more joints, and age • Little involvement outside joints • Pauciarticular onset—girls 6X as often as boys—40% • best prognosis • Max of 4 joints, typically < 6 yrs old
Signs and symptoms of JRA • Fatigue, anorexia, weight loss, fever • Shifting, symmetrical polyarthritis; any diarthrotic joint is possible • Morning stiffness of joints > 1 hour • Erosive arthritis seen on X rays, followed by deformity
Both age groups • Rheumatoid nodules, usually indicates active or severe disease • Damage to other organs—heart, lungs, eyes, blood vessels • Normocytic, normochromic anemia if bone marrow is involved • Turbid, non-viscous synovial fluid with high WBC count • Increased T cell activity causes increased TNF, which causes increased osteoclast activity
Rheumatoid factor in 85 % of pts • IgM that reacts with altered human IgG • Anti-gamma globulin factor • Complexes ppt onto joint tissue, stim immune reaction • May show up in other AI connective tissue diseases • Seen in 5-20% of normal people • Increased incidence as get older
Systemic lupus erythematosis • Signs and symptoms are diverse, easily missed in early stages • Butterfly rash across face is classic sign (40% of cases) • AB form vs nucleic acids (anti-nuclear antibodies) • RBC, WBC, platelets, coagulation proteins, etc, • Mild to rapidly fatal • In US: incidence in Fe 10x M • Incidence in Black Fe 8x White Fe
Signs and symptoms of SLE • Symmetric arthritis or joint pain (90%)—not erosive or deforming • Fever, fatigue, weakness (50% have mild anemia), weight loss, possibly severe hair loss • Vasculitis (80%) with butterfly rash that gets worse if exposed to sunlight • Pleurisy chest pain; myocarditis, pericarditis • Anemia or other marrow deficiencies
Renal complications • Antinuclear antibodies attach to DNA, deposit in glomerulus • Complement attaches to immune complex, renal inflammation begins • 65% of SLE pts develop glomerulonephritis • 40% have clinical renal disease • 25% have severe renal damage (renal failure) • CNS complications usually fatal • Diagnose with + antinuclear antibody test
Scleroderma • Now called Progressive Systemic Sclerosis • Usually starts in 20‘s-40’s, least common of diseases mentioned here • Disease is overproduction of collagen, may be localized or systemic • Slow, progressive fibrosis of skin and other organs • Proliferation of collagen in walls of blood vessels—lose elasticity
Localized scleroderma—restricted to skin • May occur as result of repeated exposure to some chemicals • Milder, better prognosis
Generalized scleroderma • Limited cutaneous systemic sclerosis (Raynaud’s phenomenon) • Vasospasm when extremities are exposed to cold • Digits become white, then blue, then red in each attack • Thickening and tightening of skinsausage appearance • Diffuse cutaneous—CT of skin and viscera, rapid progression
Progression of Scleroderma • Gradually spreads up limbs, involves trunk, face • Very taut face, wrinkled mouth, smooth forehead • Arthritis, joint pain and stiffness common • Esophageal dysfunction, GI dysfunction • Decreased pulmonary volumes • Renal vessels damaged—proteinuria, hematuria, hypertension • Renal failure is leading cause of death for generalized scleroderma