autoimmune disease Flashcards
(23 cards)
What is autoimmune disease?
A failure of self-tolerance and subsequent adaptive immune responses against self-antigens.
What are the factors that contribute to autoimmune disease?
Genetic factors(HLA), infection (molecular mimicry), and environmental factors. All lead to breakdown of self-tolerance.
What is immune tolerance?
Lack of response to an antigen that is induced by previous exposure of lymphocytes to that Ag.
What is central tolerance?
Immunological tolerance to self antigens induced in immature lymphocytes in generative/central lymphoid organs.
What are the mechanisms of central tolerance?
Deletion, receptor editing (BCR), regulatory T cell development (CD4+)
What is positive T cell selection in the central tolerance?
A low affinity interaction of TCR with self MHC positively selects and rescues thymocytes from program cell death.
What is negative T cell selection in central tolerance?
High-avidity recognition of self peptide-MHC complexes and deletes/apoptotic death of cell.
What is peripheral immune tolerance?
Immune tolerance in peripheral tissue of mature lymphocytes: Clonal anergy (no B7CD28:), deletion, suppresion via Treg (IL-10, TGF-b).
What is mucosal immune tolerance?
Antigens or antibodies administered via oral/nasal can develop a immune tolerance via ignorance (anergy), deletion, Treg (decrease inflammation).
What deficiency causes SLE?
Complement proteins C1q, C2, or C4.
What is type 2 hypersensitivity?
Antibody dependent cytotoxic. Mediated by IgG and IgM. Cell lysis, cell injury, phagocytosis.
What is type 3 hypersensitivity?
Immune complex formation that is deposited in tissue and blood vessel walls. Causes inflammation and tissue damage due to inflammation
What is type 4 hypersensitivity (DTH)?
Delayed type hypersensitivity (DTH) is T-helper cell (CD4) mediated inflammatory response. Found in transplant rejection, contact dermatitis, tuberculin-type hypersensitivity.
Lupus nephritis
Caused by anti-dna ab
autoimmune anemias, thrombocytopenia
Caused by complement fixing abs
SLE, RA, Type 1 diabetes
Tissue specific abs
Graves disease, myasthenia gravis
autoantibodies to cell surface receptors. Graves disease is hyperthyroidism. Myasthenia gravis is muscle weakness and paralysis.
Vasculitis
Inflammation of blood vessels from immune complex deposition
Glomerulonephritis
Inflammation of the glomeruli in kidney caused by immune complex deposition.
Autoimmune hemolytic anemia
RBC lysis via complement-fixing autoantibodies.
Molecular mimicry
Auto-reactive B cells that recognize self-antigen and also cross react with foreign antigen. Rheumatic fever via group A streptococcal.
T-cell mediated autoimmune disease
Type 1 diabetes, rheumatoid arthritis, multiple sclerosis, hasimoto’s thyroiditis (hypothyroidism)
Rheumatoid arthritis and periodontitis connection
P. gingivalis produces citrullinated peptides and antibodies produced against it. Citrullinated proteins present in gingiva and synovial fluid
