disorders - rheumatic fever 4 Release of hidden or...

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DISORDERS OF THE IMMUNE SYSTEM Autoimmune Diseases A. Develop immunity to “self”-Ag. on host tissues autoantibodies, T lymphocytes B. Development autoimmunity destruction host tissues C. Immunological tolerance - ability to recognize “self” vs “non-self.” D. Due to: 1. Clonal deletion a. Develops during prenatal period. b. B lymphocytes with immune receptors to “self” Ag. destroyed c. Do not develop immunity to host tissues. 2. T S lymph prevents development of immunity to “self” Ag. E. Possible Causes of Autoimmunity 1. Genetic predisposition - due to faulty gene a. Direct cause b. Makes individual more susceptible to other causes 2. Altered self-ag. a. Mutations – cause changes in structure host cells b. Self-Ag. altered or new Ag. inserted into host cell membranes (viruses, drugs, chemicals) c. No longer recognized as self auto antibodies 3. Cross reactions a. Ab. developed against hapten or whole Ag. b. Ab. also reacts with self-Ag. (cross reaction) c. Ex. Streptococcus pyogenes
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Unformatted text preview: - rheumatic fever 4. Release of hidden or sequestered Ag. a. Not all Ag. . exposed to immune recognition system during embryonic development. b. If self-Ag. released into system later (due to injury, illness) → production of autoantibodies 5. Lack of T S lymph, dysfunction of T S lymph - As age # T S lymph decreases and # autoimmune diseases increases Genetic Defects of Immune System A. B-lymph defects → Agammaglobulinemia 1. Due to failure of B lymph to differentiate into plasma cells (Ab. producing cells) 2. The absence of immune receptors (IgD) on B lymphocytes B. T-lymph defects → DiGeorge syndrome 1. Failure to develop functional thymus gland 2. Do not cellular immunity 3. May develop low grade humoral immunity (hypogammaglobulinemia), C. T & B lymph defects - severe combined immunodeficiency disease (SCID) 1. Defect in stem cell - failure to develop mature T & B lymphocytes 2. Failure to develop immunity...
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disorders - rheumatic fever 4 Release of hidden or...

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