1 / 57

MICROBIOLOGY- ALCAMO

MICROBIOLOGY- ALCAMO. LECTURE: IMMUNE DISORDERS. IMMUNE DISORDERS. Faulty immune system can either: Over-react or Under-react. Introduction – Hay Fever. Hay fever – not dangerous, but causes great discomfort and inconvenience

tulia
Download Presentation

MICROBIOLOGY- ALCAMO

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MICROBIOLOGY- ALCAMO LECTURE: IMMUNE DISORDERS

  2. IMMUNE DISORDERS • Faulty immune system can either: • Over-react or • Under-react

  3. Introduction – Hay Fever • Hay fever – not dangerous, but causes great discomfort and inconvenience • 1870’s – British scientist Charles Blackley found that pollen grains could: • When placed in the eyes of some people, cause swelling • When rubbed into a skin scratch produce a local reaction

  4. Introduction Hay Fever • Now a known disorder of the immune system • About 35 million Americans suffer from hay fever • Thousands more are allergic to foods, cosmetics, leather or metals, and pets • Approximately 40-50 million people in the U.S. have some type of allergy

  5. Introduction – Hay Fever • The common denominator among allergies is hypersensitivity • Hypersensitivity stems from the activity of the immune system and involves both • Antibody mediated immunity • Cellular aspects of immunity • Currently intense research is going on to find ways to alleviate allergy symptoms

  6. Hypersensitivity • Multi-step phenomenon requiring: • Initial exposure to an antigen • Dormant stage when person is sensitized • Reaction to a second exposure to antigen • Reaction can be: • Immediate – response by antibodies within minutes • Delayed - cell mediated response over 2-3 days

  7. Hypersensitivity • Early 1970’s Gell and Coombs further classified Hypersensitivities • Immediate Hypersensitivity • 1. Type I Anaphylactic Hypersensitivity • 2. Type II Cytotoxic Hypersensitivity • 3. Type III Immune Complex Hypersensitivity • Delayed Hypersensitivity • 4. Type IV Cellular Hypersensitivity

  8. TYPE 1 ANAPHYLACTIC HYPERSENSITIVITY • Begins with entry of antigenic substance (allergens – bee venom, serum proteins, drugs, etc) • Sensitizing Dose – smallest dose of an allergen that sensitizes a person to cause a reaction (can be as low as 0.001 mg) • Immune system responds and B-lymphocytes produce IgE

  9. TYPE 1 ANAPHYLACTIC HYPERSENSITIVITY • IgE enters circulation and attaches to thousands of: • Mast cells (connective tissue cells with granules) • Basophils (white blood cells with granules) • Granules are released, flow into extracellular fluids and emit mediators: • Histamine • Serotonin

  10. TYPE 1 ANAPHYLACTIC HYPERSENSITIVITY • Mediators – principal activity is to contract smooth muscles in the body - Anaphylaxis • This constricts veins and capillaries and forces fluid out into the tissues • The skin becomes swollen around the eyes, wrists and ankles – called edema • This is accompanied by a hive-like rash and burning and itching of the skin as nerves are excited

  11. TYPE 1 ANAPHYLACTIC HYPERSENSITIVITY • Contractions also occur in the gastrointestinal tract (causes sharp cramps) and bronchial muscles (causes shortness of breath) • Person inhales rapidly, but can’t exhale to get rid of CO2 • Death can occur within 10-15 minutes due to asphyxiation

  12. WHOLE BODY INVOLVEDGet medical help fast!!!!!

  13. Medical Help • Adrenalin – stabilizes basophils and mast cells, opens air passages and constricts capillaries • Muscle relaxer – opens air passages, stops cramping • Antihistamine – competes with histamine for active sites on smooth muscle cells and inhibits histamine’s actions • If all else fails - tracheostomy

  14. TYPE 1 ANAPHYLACTIC HYPERSENSITIVITY • Desensitization – therapy used to reduce the possibility of anaphylaxis • Short-term - can inject tiny but increasing amounts of allergen over a period of hours to induce a gradual reduction of granules rather than a later massive degranulation • Long-term - can give a series of injections of allergen over a few weeks and the exposure causes immune system to produce IgG which can neutralize sensitized cells.

  15. Atopic Disease/Allergy • Also Type I Hypersensitivity, but in localized areas • Hay Fever: • immune stimulation by pollen antigens leads to IgE production • sensitization of mast cells in the eyes, nose and upper respiratory tract • Subsequent exposure causes the all too familiar sneezing, tearing and swollen mucous membranes

  16. Asthma • Asthma attacks are triggered by allergic reactions • Characterized by wheezing and stressed breathing • 15 million Americans suffer from asthma • Doctors usually prescribe bronchodilators and/or anti-inflammatory agents (steroids)

  17. Food Allergies • Characterized by symptoms in the gastrointestinal tract • Swollen lips • Abdominal cramps • Nausea and diarrhea • May develop urticaria – rash containing hives • Allergenic foods – chocolate, strawberries, oranges, cow’s milk and fish

  18. Why Me???? • Almost 20 % of Americans have some sort of allergy • Allergic individuals have 100 times the IgE level of normal individuals • Hypotheses: • IgA levels are greatly reduced in people with allergies. In normal people IgA may shield IgE lymphocytes from antigenic stimulation • Immune system feedback mechanisms are defective in allergic individuals (suppressor T-lymphocytes)

  19. Type II Cytotoxic Hypersensitivity • Cell-destroying reaction that occurs when IgG reacts with antigens on the surface of target cells • Transfusion reaction – mixing incompatible blood types • Human Blood Types: A, B, AB and O • Each type has antigens on the surface of RBC’s • If given the wrong blood type, a person’s antibodies will react with the antigens and agglutination (clumping) occurs

  20. Hemolytic or Rh Disease • 85-90% of Americans’ RBC’s have a surface antigen (Rh) and are Rh+ • If an Rh- woman marries an Rh+ man, there is a 75% chance the baby will be Rh+ • A first pregnancy will stimulate the production of Rh+ antibodies in the woman • In any subsequent pregnancies, the woman’s body will see the baby’s blood as foreign and destroy its blood cells • Treatment – injection of Rh antibodies within 72 hours of birth will remove Rh antigens from blood

  21. Autoimmune Diseases – Fighting Yourself • Thrombocytopenia – antibodies produced against thrombocytes • Leads to impaired blood clotting and hemorrhages on skin and mouth

  22. Goodpasture’s Syndrome • Antibodies combine with antigens in the kidneys and lungs • Can cause kidney and lung failure

  23. Myasthenia Gravis • Antibodies generated against muscle fiber membranes • Reduces nerve impulse transfer and results in loss of muscle activity, weakness, fatigue

  24. Graves’ Disease • Antibodies unite with receptors on the surface of thyroid gland cells causing increased secretion of thyroxine • This results in goiter and rise in metabolic rate

  25. TYPE III Immune Complex Hypersensitivity • When antibodies combine with antigens and form aggregates that accumulate in blood vessels or on tissue surfaces • Phagocytes are attracted to site and enzymes are released that cause tissue damage • Gradual development – usually not life threatening • Serum sickness – IgG produced against serum proteins – can cause kidney damage

  26. TYPE III Immune Complex Hypersensitivity • Systemic lupus erythematosus: • as old white blood cells are • disintegrating, B-lymphocytes produce IgG • Immune complexes accumulate in the skin and body organs • Causes butterfly rash and lesions in the heart, kidney and blood vessels

  27. Rheumatoid Arthritis • Immune complexes form in the joints causing inflammation - debilitating • Chronic disease – may have periods with no pain, but then it returns

  28. TYPE IV Cellular Hypersensitivity • T-cells involved • Delayed Reaction – maximal effect not seen until 24-72 hours has elapsed • Characterized by: • Induration - a thickening and drying of the skin tissue • Erythema – surrounding zone of redness

  29. TYPE IV Cellular Hypersensitivity • There is a localized reaction with lumps, hives or blisters • Contact dermatitis can develop after exposure to many different allergens (clothing, jewelry, cosmetics, fur) • For example: Poison ivy oil on leaves is an allergen

  30. IMMUNE DEFICIENCIES • Bruton’s Agammaglobulinemia: • Congenital disease • B-lymphocytes fail to develop in the bone marrow • No antibodies are made • Can’t fight infectious disease

  31. IMMUNE DEFICIENCIES • DiGeorge’s Syndrome: • Congenital disease • T-lymphocytes don’t develop because of failure in thymus gland • Cellular immunity is defective • Susceptible to fungal and protozoal diseases

  32. IMMUNE DEFICIENCIES • Severe Combined Immunodeficiency (SCID) • Congenital disease • Defects in both antibody and cellular immunity • All immune function is suppressed • David – longest surviving victim • Lived in a sterile, plastic bubble at Baylor College of Medicine for 12 years • Received a bone marrow transplant from his sister but died of blood cancer

  33. http://www.bbc.co.uk/news/health-11451810

  34. Acquired Immune Deficiency (AIDS) • Viral disease • Cellular immunity severely depressed • Antibody-mediated immunity also altered • Have very few T—cells • Ratio of T-cells is reversed: • Normal 2 Helper T-cells:1 Suppressor T-cell • AIDS 1 Helper T-cell:2 Suppressor T-cells

More Related