tolerance, autoimmunity, and autoimmune diseases Flashcards
define immunologic tolerance
acquisition of nonreactivity toward particular self-antigens
what is the major mechanism of self tolerance
elimination of self-reactive immature lymphocytes
failures of tolerance can result in
rxn to self antigen
hypersensitivty rxns to non-self
antiinflammatory w/ no antigen
three pathways recognized for T cell tolerance
clonal abortion
funcitonal deletion
t cell suppression
what organ is responsible for deleting autoreactive t cells w/ potential to cause disease
thymus
what happens to B cells liklihood of tolerance as it matures
less susceptible to tolerization
four pathways for b cell tolerance
clonal abortion
clonal exhaustion
functional deletion
antibody-forming cell blockade
what is the hallmark of autoimmune disease
tissue injury caused by t lymphs or antibody reactivity to self
if autoimmune disorder activates innate immunity what happens
prolonged/excess inflammation from macrophage cytokine release
Characteristics of organ-specific autoimmune disorders
produced by t cells or antibodies against antigens restricted to a single organ
- T1D, MS and thyroid
characteristics of organ-non-specific autoimmune disorders
systemic autoimmune disease is produced by circulating antibodies or immune complexes that affect multiple organs
- SLE and RA
characteristics of mid spectrum disorders
localized lesions in single organ and organ-non-specific autoantibodies
all of the following characteristics are common to organ-specific and organ-nonspecific disorders except
a. autoantibody tests are of diagnostic value
b. antibodies may appear in each of the main Ig classes
c. antigens are available to lymphoid system in low concentrations
d. circulatory autoantibodies react with normal body constituents
c. antigens are availble to lymphoid system in low concentrations
antibody expression in the development of autoimmunity is regulated by all except
a. genetic predisposition
b. increasing age
c. environmental factors
d. active infectious disease
d. active infectious disease
the mechanism responsible for autoimmune disorder is
a. circulating immune complexes
b. antigen excess
c. antibody excess
d. antigen deficiency
a. circulating immune complexes
one of the mechanisms believed to induce self-tolerance is
a. induction of responsiveness in immunocompetent cells
b. elimination of clone programmed to react with self antigen
c. decreased suppressor cell activity
d. stimulation of clones of immunocompetent cells
b. elimination of clone programmed to react with self antigen
what antibody is useful in monitoring activity and exacerbations of autoimmune disease SLE
anti-DNA antibodies
self-tolerance is induced by
a. Burnet clonal selection theory
b. elimination of the smaller clone of immunocompetent cells programmed to react with the antigen
c. induction of unresponsiveness in the immunocompetent cells through excessive antigen binding
d. all of the above
d. all of the above
decribe vasculitis
cardiovascular, midspecturm disorder of the blood vessels
- deposition of circulating immune complexes
describe carditis
cardiovascular disorder of the heart
- primary idiopathic myocarditis; infiltration of heart by lymphs and macros
describe scleroderma
collagen vascular disease, chronic multisystem causing thickening of the skin
- cell hyperactivity correlates ith disease activity
describe eosinophilia-myalgia syndrome
caused by exposure to L-tryptophan (1974)
collagen vascular disorder
what are the two major forms of autoimmune thyroid disease
chronic autoimmune thyroiditis
graves disease
what is the autoimmune process of chronic thyroiditis
development of circulating cytotoxic antibodies eventually destroys the thyroid gland
- hypothyroidism
what antibodies are present in chronic thyroiditis
- thyroglobulin
- thyroid microsome: low titers correlate with thyroid involvement
- CA2 antigen: present in 50% of subacute thyroiditis (against colloid protein)
- thyroid membrane receptor: IgG antibodies to produce hyperthyroidism
- T4 and T3: found in hypothyroidism
diagnostic eval of chronic thyroiditis
increased TSH, decreased T4/T3 w/ anti-TPO antibodies present
diagnostic eval of Graves disease
hyperthyroidism, low TSH, elevated T4 and T3
insulin-dependent diabetes mellitus is caused by what
immune destruction (initiated by CD4) by beta cells of pancreatic islets causing low insulin lvls and exogenous insulin dependence
describe Sjogren syndrome
a chronic inflammatory disease of endocrine glands that affects lacrimal, salivary, and other excretory glands
What are the two most common skeletal muscle disorders
polymyositis and dermatomyositis
