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Chapter 18 Lecture 6 (Autoimmunity affecting endocrine organs (Type I…
Chapter 18 Lecture 6
Autoimmunity affecting endocrine organs
Autoimmune responses can develop against cells in the pancreas or the thyroid gland
Can cause destruction of the gland and hormone deficiencies
Type I diabetes mellitus
Attack on the islets of Langerhans results in the loss of the ability to make insulin
Exact trigger is unknown but many pts. Had a severe viral infection some months before the onset of diabetes
Some pts are known to have a genetic predisposition to developing type I diabetes that is associated with the possession of certain class I MHC molecules
Treatment with immunosuppressive drugs can delay the onset in some pts.
Auto immune response can lead to stimulation rather than stopping or destroying the gland tissue
Graves’ disease
Autoimmune response against the thyroid gland
Could be triggered by a viral infection of those with certain genetic backgrounds
Triggers excessive production of thyroid hormone and growth of the thyroid gland (goiter, protruding eyes, rapid hr, fatigue, & wght loss
Treated with antithyroid medication or radioactive iodine
Surgical removal of the thyroid is sometimes required
DiGeorge syndrome
T cell deficiencies alone
Thymus does not develop so no T-cells
Generally die of viral infections while remaining resistant to most bacteria
Treat with thymic stem cell transplant
Autoimmunity affecting nervous tissue
MS- Multiple Sclerosis (Type IV Hypersensitivity)
Exact cause is unknown, but thinking that a cell-mediated immune response against a bacterium or virus generates cytotoxic T-cells that mistakenly attack and destroy the myelin sheaths that insulate the brain and spinal cord
Deficits in vision, speech, and neuromuscular function
Mild, and intermittent or may be progressive, paralytic and perhaps fatal
Rheumatoid arthritis(discussed earlier) this is an autoimmune disorder affecting connective tissue
Immunodeficiency Diseases
To say the least, you probably have noticed that during periods of emotional or physical stress…. You get sick (cold)
Stress has long been known to decrease how efficient your immune system works
Similarly, chronic defects in the immune system typically first become apparent when affected pts become sick more often from infections of opportunistic pathogens
These are the hallmarks of immunodeficiency diseases- which are conditions resulting from a defective immune mechanism
Bruton-type agammaglobulinemia
Lack of B cells and thus a lack of immunoglobulins
Inherited that usually affects boys
Experience recurrent bacterial infections but usually resistant to viral, fungal, and protozoan infections
Two general types
Primary immunodeficiency diseases
Result from some genetic or developmental defect
Develop in infants and young children
Acquired immunodeficiency diseases
Develop as a direct consequence of some other recognized cause, malnutrition, severe stress, or other infectious diseases
Develop in later life
Chronic granulomatous disease
Children have recurrent infections characterized b the inability of their phagocytes to destroy bacteria
Their bodies have an inherited inability to make reactive forms of oxygen, which is necessary to destroy phagocytized bacteria
Severe combined immunodeficiency (SCID)
Where children do not make T-cells nor B cells and cannot mount immune responses
No resistance to any type of infection which can lead to rapid death
Examples of Autoimmune Diseases
Regardless of the specific mechanism that causes an autoimmune disease; they are categorized into two major groups
Systemic autoimmune diseases such as lupus
Single-organ autoimmune diseases
Can affect many different organs – can affect them individually
Blood cells
Endocrine glands
Nervous tissue
Connective tissue
Autoimmunity affecting blood cells
Autoimmune hemolytic anemia (Type II Hypersensitivity)
Individuals produce antibodies against red blood cells
Speeds up destruction of the RBC
Causes severe anemia
Precise cause is unknown
Some cases follow viral infection or treatment with certain drugs, both alter the surface of the RBC