Immune Flashcards
REQUIREMENTS OF AUTOIMMUNITY
● The presence of an immune reaction specific for some self antigen or self tissue
● Not secondary to tissue damage but is of primary pathogenic significance
● Absence of another well-defined cause of the disease
Diseases mediated by antibodies
Hemolytic anemia Thrombocytopenia atrophic gastritis of pernicious anemia Myasthenia gravis Graves disease goodpasture syndrome SLE
Diseases mediated by T cells
T1 DM Multiple sclerosis Rheumatoid arthritis Systemic sclerosis Sjogen sydndrome
Diseases postulated to be autoimmune
IBD Primary biliary cirrhosis Autoimmune hepatits Polyarteritis nodosa Inflammatory myopathies
Phenomenon of unresponsiveness to an antigen
induced by exposure of lymphocytes to that
antigen
IMMUNOLOGIC TOLERANCE
CENTRAL TOLERANCE:
Originates in the_______
primary lymphoid organs
Process where your immature T cells
express receptors specific to self
antigen. When these proliferate, they are
self reactive. The body kills these cells
through apoptosis
Negative Selection or clonal deletion
T cells (thymus)
stimulates expression of
some peripheral tissue restricted self
antigens in the thymus and is thus critical
for deletion of immature T cells specific
for these antigens
AIRE (autoimmune
regulator)
Cells are still intact but the receptor is
changed into another type so that the
potentially reactive lymphocyte will no
longer react to its own tissue.
● Receptor Editing
This occurs when self-reactive cells escape the
central lymphoid organs reaching the periphery
and so the mechanisms are also different.
PERIPHERAL TOLERANCE
The best-defined regulatory T
cells are___ cells that express high
levels of CD25, the α chain of the IL-2
receptor, and FOXP3,
CD4
Activation of antigen-specific T cells
requires two signals:
recognition of peptide antigen in association with self MHC molecules on the surface of APCs and a set of costimulatory signals (“second signals”) from APCs
binds ligand of T cell from your APC.
If this signal is absent or is unresponsive
there is no binding. This is failure to
respond
co-stimulatory signal (such as CD28),
HLA associated diseases
RA T1 DM Multiple sclerosis SLE Ankylosing spondylitis (100-200) Celiac disease
which
encode your tyrosine phosphatase and involved
in Rheumatoid Arthritis and Type 1 DM and
Inflammatory bowel disease
genes associated with your PTPN22
Best known for inflammatory bowel
disease.
- associated with crohn’s disease
NOD2
Polymorphisms in the gene encoding
the IL-2 receptor (CD25) are associated
with
Multiple sclerosis
antibodies against strep proteins
cross react with myocardial proteins and cause
myocarditis. The immune responses initially
directed against microbial antigens, also result in
activation of self-reactive lymphocytes. Aside
from attacking just the strep protein, it also
attacks own tissue
Rheumatic Heart Disease
Some viruses, such as EBV and HIV, cause _______, which may result
in production of autoantibodies.
polyclonal B-cell activation
T or F
infections promote low-level
IL-2 production, and this is essential for
maintaining regulatory T cells
T
In addition to infections, _____causes cell death and may lead to the
exposure of nuclear antigens, which elicit
pathologic immune responses in lupus; this
mechanism is the proposed explanation for the
association of lupus flares with exposure to
sunlight.
ultraviolet (UV)
radiation
T or F
Smoking is a risk factor for rheumatoid arthritis,
perhaps because it leads to chemical
modification of self antigens.
T
Autoimmune disease involving multiple organs,
characterized by a vast array of autoantibodies,
particularly antinuclear antibodies (ANAs), in
which injury is caused mainly by deposition of
immune complexes and binding of antibodies to
various cells and tissues
SYSTEMIC LUPUS ERYTHEMATOSUS
In SLE, injury to the _____________ is prominent.
The disease is very heterogeneous, and any
patient may present with any number of these
clinical features
skin, joints, kidney, and serosal
membranes
SLE is a Type___Hypersensitivity Reaction
III
Clinical/immunologic criteria: (this is important to
the diagnosis of SLE) cutaneous lupus ____(acute) & ____ (chronic).
malar rash; discoid rash
A RASH POINT MD
Mnemonic: A RASH POINT MD
● Arthritis
● Renal disease, ANAs, Serositis, Hematological
disorders
● Photosensitivity, Oral Ulcers, Immunological
Disorders, Neurological Disorders
● Malar Rash, Discoid ulcers
For a patient to be classified having SLE you need to have ______ both have clinical and
immunological.
4/11 of criterion
The hallmark of SLE is the production of
autoantibodies, several of which (_________) are virtually diagnostic
antibodies to
double-stranded DNA and the so called Smith
[Sm] antigen
ANA’s. These are directed against nuclear Ag
and can be grouped into four categories based
on their specificity for:
○ DNA
○ Histones
○ Non histone proteins bound to RNA
○ Nucleolar Ag
is the most
widely used method for detecting ANA, which can
identify Ab that binds to a variety of nuclear Ag.
The pattern of nuclear fluorescence suggests the
type of Ab present in a patient’s serum
Indirect Immunofluorescence
● Antibodies to chromatin, histones and
occasionally, double stranded DNA
● Most specific
Homogenous or diffuse nuclear staining
