1. Immune System Diseases and Disorders
Chapter 4
Immune System Diseases and Disorders

2. Defense Mechanisms
Two separate defense mechanisms work together to protect an individual from disease
Inflammation:
Nonspecific
Neutrophils, eosinophils, basophils, & monocytes are active
Neutrophils & monocytes become phagocytic in the presence of pathogens
Immune system:
Specific
Acquired
Lymphocytes are the major cells of the immune response

3. Immune System Organs of the immune system Primary organs
Thymus
Bone marrow
Responsible for developing lymphocytes
Secondary organs
Lymph nodes
Spleen
Liver
Tonsils
Responsible for filtering & allowing lymphocytes to recognize foreign substances

4. Organs of the Immune System

5. Formation of Lymphocytes
Lymphocytes are a type of white blood cell
These cells are initially formed from stem cells in:
Further development will occur in either the thymus or bone marrow
This is where lymphocytes “learn” their function a process called:

6. Formation of Lymphocytes
2 types of lymphocytes
B lymphocytes
T lymphocytes
Mature B & T lymphocytes enter the blood, circulate & colonize lymphatic organs

7. Acquired Immunity
2 types :
Humoral immunity
Cell mediated immunity

8. Acquired Immunity Humoral immunity Also called:
B lymphocytes become activated by antigens
Antigens are:
Self-antigens:
Non-self antigens:
Once activated B lymphocytes will respond in two ways
They will either become a plasma cell or a memory cell

9. Acquired Immunity Humoral immunity contd. Plasma cells
Divide rapidly & produce large numbers of antibodies
Antibodies are also called:
Function of antibodies:
Memory cells

10. Specific Immunity: Humoral
Review Table 4-2 pg. 54: Types & Functions of Immunoglobulins

11. Acquired Immunity Cell mediated immunity
T lymphocytes are the major cells
Functions:
Can only respond to processed antigens
Processed by:
Processing involves:
T lymphocytes that have a corresponding antigen respond by:
There are different types of T-cells with different functions which is summarized in Table 4-1 and on pgs

12. Acquired Immunity

13. Acquired Immunity Lag of Response
After initial contact with a foreign antigen it will take a week or more to respond
This is due to:
Memory cells that develop will allow the immune system to respond quicker with any subsequent exposure

14. Acquired Immunity
Everyone is born with some natural immunity but immunity is also acquired
4 types of acquired immunity:
Active natural
Individual is exposed to disease-causing microorganism
Body learns to produce antibodies
Active artificial
Vaccination (dead or attenuated)
Body produces antibodies
Passive natural
Transfer of antibodies from mom to baby
Passive artificial
Inoculation with antibodies

15. Immunity

16. Immune Diseases
Diseases of the immune system are divided into 2 groups
Hypersensitivity disorders
Autoimmune disorders

17. Immune Diseases Hypersensitivity reactions:
Occurs when an immune response causes associated tissue damage
Classified based on how they cause the damage
4 different types
Antibody-mediated hypersensitivity
Type I: immediate hypersensitivity
Type II: cytotoxic
Type III: immune complex
Cell-mediated hypersensitivity
Type IV: delayed hypersensitivity
These different types are summarized in Table 4-3

18. Immune Diseases: Hypersensitivity
Type I: immediate hypersensitivity
Atopic person becomes sensitized following contact with:
IgE antibodies are produced and attach to the surface of:
The exposure of a person to a sensitizing antigen will cause:
Immediate hypersensitivity reactions may either be:
Localized:
Systemic:

19. Immune Diseases: Hypersensitivity
Type I: immediate hypersensitivity
Allergy:
To plant pollens and other antigens that don’t effect most people
Sensitizing antigen is called:
Symptoms will be localized to:
Treatment:
Examples of localized allergic reactions:
Allergic asthma
Allergic rhinitis (hay fever)
Urticaria (hives)
Localized angioedema
Food allergy

20. Urticaria

21. Localized Angioedema

22. Immune Diseases: Hypersensitivity
Anaphylaxis:
Severe generalized IgE-mediated reaction
The exposure of a sensitized person to a sensitizing antigen (allergen) will cause:
Release of these mediators can cause:
Common allergens include:
Prompt treatment required with:
If not treated quickly:

24. Anaphylaxis: systemic angioedema

25. Immune Diseases: Hypersensitivity
Type II: Cytotoxic Hypersensitivity
Antibody combines to cell or tissue antigen resulting in complement-mediated lysis of cells or other membrane damage
Ex: Blood transfusion reactions, hemolytic disease of the newborn, and a few other similar disorders

26. Hypersensitivity Disorders
Type II: Cytotoxic Hypersensitivity
Blood transfusion reaction:
Cause:
If a blood type with an antigen is given to someone with an antibody against that antigen
Antibody attacks the antigen & breaks down RBC’s
Symptoms:
Chills, fever, increased heart rate, & shortness of breath
Treatment:
Discontinue transfusion
Treat symptoms that arise
Can lead to death

27. A X X B X X AB X X O X X

28. Hypersensitivity Disorders: Isoimmunity
Type II: Cytotoxic Hypersensitivity
Hemolytic disease of the newborn
Also know as erythroblastosis fetalis
mothers antibodies attack & destroy antigen on baby’s RBCs
Can be fatal to fetus

29. Rh Blood Group Rh blood types
If RBCs have Rh antigen: Rh+
If RBCs lack Rh antigen: Rh–
Rh+ blood type in % of U.S. population
Normally neither Rh+ nor Rh– has anti-Rh antibodies
Antibodies develop in Rh- person after first exposure to Rh+ blood (as in having a first child who is Rh+)
This is the cause for erythroblastosis fetalis

30. Hypersensitivity Disorders: Isoimmunity
Erythroblastosis Fetalis:
Cause:
Mothers Rh antibodies attack 2nd Rh+ baby’s RBCs
Symptoms:
Baby will develop anemia possibly leading to death
Treatment:
Blood transfusion
RhoGAM injection for mom around time of delivery
Prevents mom from developing Rh antibodies

31. Immune Diseases: Hypersensitivity
Type III: Immune Complex
Antigens and antibodies form immune complexes
Immune complexes deposited in tissues activate complements; polymorphonuclear leukocytes attracted to site, causing tissue damage
Ex: rheumatoid arthritis & systemic lupus erythematosus (SLE)
Both of these are classified as autoimmune and are discussed in upcoming slides.

32. Immune Diseases: Hypersensitivity
Type IV: Delayed Hypersensitivity (cell-mediated)
Caused by T lymphocytes instead of:
T lymphocytes are sensitized and activated on second contact with same antigen
Activated T lymphocytes secrete complement cytokines which attract & activate macrophages & lymphocytes that initiate inflammatory response
Intense cell-mediated inflammatory reaction in the skin is called:
May follow exposure to:

33. Contact Dermatitis

34. Hypersensitivity Disorders
Autoimmune disorders
A person forms autoantibodies against his/her own cells or tissues
2 possible reasons for this are:
Alteration of patient’s own (self) antigens causing them to become antigenic, provoking an immune reaction
Formation of cross-reacting antibodies against foreign antigens that also attack patient’s own antigens
Cause:
Theory states that a pathogen has antigens that resemble our own
Table 4-4 shows common autoimmune diseases, some of which are discussed in the next few slides.

35. Hypersensitivity Disorders: Autoimmunity
Rheumatic Fever: A complication of strep throat
Cause:
Follows an infection with group A streptococcus
Body makes antibodies against bacterial antigens
Some individuals contain antigens on their tissues that resemble the bacterial antigens
Antibodies attack tissues of heart and joints
Symptoms:
Fever, malaise, and joint pain occur 1-4 weeks after strep infection
Usually children or young adults
Further episodes can lead to scarring of heart valves
Treatment:
Antibiotics

36. Hypersensitivity Disorders: Autoimmunity
Rheumatoid Arthritis: chronic inflammation of connective tissue, especially in joints
Cause:
An abnormal antibody attacks bodies own cells & tissues
A blood test would show presence of antibody called rheumatoid factor
Symptoms:
Begins with inflammation of synovial membrane of joint which leads to pain, stiffness and joint deformity.
Over time joint will be replaced with fibrous tissue decreasing mobility (called ankylosis)
Metacarpal-phalangeal joints usually affected first leading to ulnar deviation of digits

37. Hypersensitivity Disorders: Autoimmunity
Rheumatoid Arthritis:
Symptoms (cont.):
Rheumatoid nodules may appear in sub-q tissue around fingers, toes, & elbows
3 times more likely to occur in women with an onset between the ages of 20-40
Called juvenile rheumatoid arthritis if occurring in children under the age of 16.
Pluritis, valvulitis, and glaucoma may occur
Treatment:
Anti-inflammatory medication & analgesics
Exercise may help with mobility as well as joint replacement

38. Rheumatoid Arthritis

39. Hypersensitivity Disorders: Autoimmunity
Myasthenia Gravis: characterized by muscular fatigue
Cause:
Antibodies attack acetylcholine (Ach) receptors
Leads to muscle weakness

40. Hypersensitivity Disorders: Autoimmunity
Myasthenia Gravis:
Symptoms:
Onset is slow and can affect any muscle in the body making diagnosis difficult
Smaller muscles are commonly affected first including those of the face and eyes
Diplopia: double vision
Ptosis: drooping eyelids
Dysphagia: difficulty swallowing
Dysphonia: difficulty talking
Difficulty with facial expressions
Fatigue: difficulty standing, walking, & lifting arms

41. Hypersensitivity Disorders: Autoimmunity
Myasthenia Gravis:
Symptoms cont.:
Weakness tends to increase as the day progresses
Ach stores become depleted
Increased activity leads to fatigue
Rest increases muscle function
Treatment:
Cholinergic medicine that prevents break down of Ach
Plasma exchange to remove circulating antibodies

42. Myasthenia Gravis

43. Hypersensitivity Disorders: Autoimmunity
Type I Diabetes Mellitus: altered sugar metabolism
Cause:
Infection causes body to produce autoantibodies which destroy pancreatic beta cells
Possibly rubella, mumps, or influenza
Symptoms:
Elevated blood sugars
Treatment:
Insulin injections

44. Hypersensitivity Disorders: Autoimmunity
Lupus Erythematosus: 2 kinds
Cutaneous or discoid (DLE)
Limited to skin
Systemic (SLE)
Affects many body systems
Cause:
Autoantibodies cause widespread injury to tissues & organs

45. Hypersensitivity Disorders: Autoimmunity
Lupus Erythematosus
Symptoms:
Fever, joint pain, weight loss, & butterfly shaped rash over bridge of nose & cheeks
Exacerbation & remission occur
Treatment:
Symptomatic treatment
NSAIDS
Anti-pyretic (reduce fever)
Analgesics (reduce pain)
Corticosteroids used to treat life threatening exacerbation
Renal insufficiency, bacterial endocarditis, cardiac failure, sepsis, & pneumonia commonly lead to death

46. Lupus Erythematosus

47. ??QUESTIONS??