Abnormal Immunity - Immunodeficiency and Autoimmunity Flashcards
Immunopathology
Disease characterized by abnormal or inappropriate immune responses
Major conditions include:
hypersensitivity reactions
Immunodeficiency
Autoimmunity
Immunopathology:
Autoimmunity
- Immune responses directed agianst self
- Immune mechanisms that mediate autoimmunity are the same that mediate reactions agianst exogenous antigens
- only difference is the source of the antigen
Autoimmunity:
Mechanisms
- Several general theories have been made about the origin of autoreactive immunity
- release of sequestered antigens
- Alteration of self antigen
- Alteration of immune reactivity
Autoimmunity:
Mechanisms
Release of sequestered antigens
- Some substances in the body are not normally exposed to the immune system
- These include:
- myelin
- Lens
- Sperm
Autoimmunity:
Mechanisms:
Alteration of self antigens
- Self antigens may be modified so that they are no longer recognized as self
- viral alteration of cell membrane features
- Chemical alteration of cell membrane
Autoimmunity:
Mechanisms:
Alteration of immune reactivity
- There is a loss of tolerance to self antigen
- Autoreactive B- and T- lymphocytes are normally present, but non-functional
- changes may occur that allow functions of these cells to be manifested
Autoimmunity:
Predisposing Factors
- Genetic Predisposition:
- certain conditions have definite inherited patterns of breed or familial occurrence
- Gender Predisposition:
- Autoimmunity is more common in females
- over 75% of cases of systemic lupus erythematosis are diagnosed in females
- Comparative levels of estrogen and testosterone can influence autoimmunity
- Autoimmunity is more common in females
Autoimmunity:
Manifestation:
Autoimmune Thyroiditis
- Antibodies are produced against the thyroid epithelium or thyroglobulin
- Common cause of hypothyroidism in dogs
Autoimmunity:
Manifestation:
Periodic Ophthalmia
- Anti-leptospiral antibodies that are cross reactive with corneal self antigens cause anterior uveitis and vision deficiencies
Autoimmunity:
Manifestation:
Autoimmune Skin disease
- Antibodies are produced to various components of the epidermis
- Variety of different syndromes exist
- pemphigus vulgaris
- Pemphigus foliaceous
Autoimmunity:
Manifestation:
Autoimmune Hemolytic Anemia
Antibodies agianst erythrocytes result in complement or leukocyte-mediated hemolysis
Autoimmunity:
Manifestation:
Autoimmune Thrombocytopenia
- Anti-platelet antibodies destroy platelets and predispose to hemorrhage
Autoimmunity:
Manifestation:
Myasthenia Gravis
- Antibodies are produced agianst acethylcholine receptors of neuromuscular junctions causing weakness and muscle atrophy
Autoimmunity:
Manifestation:
Systemic Lupus erythematosis
- Autoantibodies are directed against a variety of tissues most likely due to a loss of immunoregulation
- Antibodies are commonly formed against nucleic acids, erythrocytes, platelets, muscle, skin, lymphocytes
Immunopathology:
Immunodeficiency
- Immunological defects that lead to depression of certain immune functions and increase susceptibility of infectious disease
- Any component of the immune system can be affected
Immunodeficiency:
Mechanisms:
Inherited defects
- Genetic abnormalities result in the failure of proper development of the immune system
Immunodeficiency:
Mechanisms:
Acquired defects
Exposure to certain infectious agents or chemicals, or nutritional deficiencies
Immunodeficiency:
Manifestation:
Combined Immunodeficiency (CID)
- Come inherited defects involve multip;e immune cells
- CID is most common in arab foals, but similar syndromes are reported in dogs, mice, and other species
- Functional B- and T- lymphocytes are absent or decreased
- Affected animals usually die before 6 months of age due to infectious disease
Immunodeficiency:
Manifestations:
Selective Immunodeficiency
- Certain genetic defects involve specific immune cells
- B-lymphocytes:
- IgM deficiency in arabs and doberman pinschers
- IgG deficiency in dogs and cattle
- T-Lymphocytes:
- Trait A-46 in friesian cattle
- B-lymphocytes:
Immunodeficiency:
Manifestation:
Viral-induced Immunodeficiency
- Large numbers of viruses can alter immune functions
- some viruses destroy lymphoid cells and tissues
- Some viruses cause lumphocyte dysfunction
- Viruses that destroy lymphoid cells and tissues include:
- Canine Parvovirus
- Canine Distemper virus
- Feline panleukopenia virus
- Bovine virus diarrhea virus
- Viruses that cause lymphocyte dysfunction include:
- feline leukemia virus
- Feline immunodeficiency virus
- Bovine Leukosis virus
- Equine infectious anemai virus
- Mareks disease Virus
Immunodeficiency:
Manifestation:
Chemical-induced Immunodeficiency
- Various chemicals reportedly induce immunosuppression
- Halogenated biphenyls
- Certain Heavy metals
- Mycotoxins
Immunodeficiency:
Manifestations:
Nutrition-induced Immunodeficiency
- Severe malnutrition or starvation will depress immune function
- Deficiencies of certain vitamins or minerals can suppress immune response
- Zinc, Magnesium
- Vitamins A, and B
Immunodeficiency:
Manifestation:
Failure of Passive Transfer
- Colostral antibodies are not obtained by the newborn
- Neonates not receiving colostrum are predispoded to infections early in life.
