AUTOIMMUNITY Flashcards
DAMAGE TO ORGANS OR
TISSUES RESULT FROM THE
PRESENCE OF THE
AUTOANTIBODY OR
AUTOREACTIVCE CELLS
AUTOIMMUNE DISEASE
SELF TOLERANCE
- Clonal deletion of relevant effector cells.
- Activation regulation of T cell
TOLERANCE MECHANISM
- Release of sequestered
antigens - Molecular mimicry
3.Polyclonal B cell activation
Antigen that are protected from
encountering the circulation are not
exposed to potentially reactive
lymphocyte
sequestered
antigen
EXAMPLE OF SEQUESTERED ANTIGEN
Myelin Basic proteins – sequestered by BBB
Sperm – Blood-testis barrie
Viral or bacterial agent contain antigens
that closely resemble self antigen.
Exposure can trigger antibody production
that in turn react with similar self-antige
MOLECULAR MIMICRY
MOLECULAR MIMICRY EXAMPLE
Poliovirus VP2 – acetylcholine receptors
Measles VP3 – Myelin Basic Protein (MBP)
Papilloma Virus E2 – insulin receptors
B CELL DEFECTS
B cell defects:
1. Abnormal expression or function of Regulatory signaling
molecules.
2. Dysregulation of cytokines
3. Changes in B cell development
the receptor for antibody that normally regulate
antibody production, may cause continual B cell stimulation.
Induce the proliferation of numerous clones of B cells
that express IgM in the absence of T helper cells. B cell can
be reactive to self antigen can be activated.
Defect: Fc receptor polymorphism
Other factors in autoimmunity
. Influence of hormones
2. Environmental condition
3. Defects in NK cells
4. Defects in the secretion of cytokines
5. Defects in apoptosis
6. Defects in complement componen
Systemic Lupus Erythematosus
(SLE)
Classic model of an autoimmune
disease
Systemic rheumatic disorder involving
multiple system
The immune response is directed
against the broad range of target
antigens
FORMS OF SLE
- Discoid (cutaneous)
Limited to the skin and is identified by biopsy of the rash that may
appear on the face, neck and scalp. - Systemic
More severe and can affect the skin, joints and almost all body system
“lupus” - Drug-induced
Antiarrhythmic – procainamide hydrochloride
Antihypertensive – Hydralazine hydrochloride
Anticonvulsants- phenytoin
Chlorpromazine, Isoniazid, Penicillin, sulfonamides - Neonatal
From passage of maternal autoantibodies, specifically anti-Ro/SS-A or
anti-La/ SS-B that can affect the skin , heart and blood of the fetus and
newborns
ETIOLOGY OF SLE
Idiopatic
1. Hormonal influences
Estrogen
Antiphospholipid syndrome – complication of surgery
2. Genetic predisposition
3. Environmental factor
UV lights may cause DNA to form thymine dimers that
can result to anti DNA
SIGNS AND SYMPTOMS OF SLE
Signs and Symptoms
Achy joints (arthralgia)
Frequent fevers >37C
Arthritis (swollen joints)
Prolonged extreme fatigue
Skin rashes
Anemia
Kidney involvement
Pain in the chest on deep breathing (pleurisy)
Butterfly-shaped rash across the cheek and nose
Photosensitivity
Hair loss
Abnormal clotting problems
Raynaud’s phenomenon
Seizure
Mouth and nose ulcers
DIAGNOSIS OF SLE
Diagnosis:
1. Malar rash
2. Discoid rash
3. Photosensitivity
4. Oral ulcers
5. Arthritis
6. Serositis
7. Renal disorders
8. Neurologic disorders
9. Hematologic disorders
10. Immunologic disorders
Ab to dsDNA, SM Ag, phospholipids
11. Presence of ANA
Neutrophil that has engulfed the antibody-coated
nucleus of another neutrophi
LE cells
Anti ds-DNA
Most specific for SLE (diagnostic)
1. Indirect Immunofluorescence (IIF)
Crithidia luciliae
2. Immunodiffusion
3. Radioimmunoassay (RIA)
4. Enzyme immunoassay (EIA) – sensitive
-most widely used
Anti-histone antibody
Histone is a nucleoprotein that is a major
constituent of chromatin
Drug induce Lupus- w/ ss-DNA
Also found in RA and biliary cirrhosis
Immunofluorescence assay
Immunoblotting
EIA
IIF- homogenous
DNA complexed to histone
Deoxynucleoprotein (DNP)
Anti- Sm (Smith)
Specific for lupus, It cannot be found in
other autoimmune
Extractable nuclear antigens represent a
family of small nuclear proteins that are
associated with uridine rich RNA
Measured by immunodiffusion,
immunoblotting, immunoprecipitation and
EIA
Anti SS-A/Ro and SS-B/Ro
Often found in cutaneous manifestations of
SLE, especially photosensitivity and
dermatitis.
Highly prevalent in scleroderma and
Sjogrens syndrome
Detected by immunoprecipitation ,
immunoblotting and EIA.
Anti- nRNP antibody
Coarsely speckled IIF pattern.
Immunoblotting, immunoprecipitation , EIA
and IIF
Produces prolonged activated partial
thromboplastic time (aPT) and prothrombin time
(PTT)
Antiphospholipid antibodies
Heterogenous group of antibodies that bind to
phospholipid alone or are complexed with protein.
Associated with deep-vein and arterial thrombosis
and with morbidity and pregnanc
Antiphospholipid antibodies
TREATMENT FOR SLE
Fever and arthritis- aspirin , antiinflammatory drug
Skin manifestation – hydroxychloroquine or
chloroquine, topical steroids
Acute fulminant lupus, lupus nephritis ,CNS
complications- systemic corticosteroids
Rheumatoid Arthritis
Strikes between 35 and 50
Characterized as chronic, symmetric and erosive
arthritis of the peripheral joints that can also affect
multiple organism such as the heart and lungs.
Can affect organs such as heart and lungs.
Associated with MHC class II which codes for beta chaiN
SIGNS OF RA
- Morning stiffness around the joints lasting at least 1 hour
- Swelling of the proximal interphalangeal,
metacarpophalangeal, or wrist joints - Symmetric arthritis
- Subcutaneous nodules
- Rheumatoid factor (RF) positive
- Radiographic evidence of erosions in the joints of the
hands, wrist or both
NON SPECIFIC SYMPTOMS OF RA
Non specific symptoms
Malaise
Fatigue
Fever
Weight loss
Transient joint pain
Nodules over bones, myocardium, pericardium, heart valves,
pleura, lungs, spleen and larynx
Systemic: anemia,subcutaneous
nodules,pericarditris,lymphadenopathy,splenomegaly,interstiti
al lungdisease,vasculitis
Chronic RA coupled with neutropenia, splenomegaly, and
possibly thrombocytopeni
Felty’syndrome
INFECTIOUS AGENTS OF RA
Mycoplasma
Rubella
Cytomegalovirus
EBV
parvovirus
IMMUNOLOGIC FINDINGS OF RA
Pannus -
Continual inflammation
Proinflammatory – IL1, 6, 8 ,15, 18, TNF-α
Collagenase / tissue degrading enzymes – released from
synoviocytes and chondrocytes that line joint cavity.
Increased cell lining of synovium and infiltration
of mononuclear cells (CD4+ lymphocytes)
-CD8+ T cells, B cells and plasma cells are scattered
- (+) Macrophage and Neutrophils
PANNUS
– released from
synoviocytes and chondrocytes that line joint cavity.
Collagenase / tissue degrading enzymes
AUTOANTIBODIES FOUND IN RA
Rheumatoid Factor- IgM directed against the FC portion of
IgG
-Not specific
Antikeratin antibody
Antiperinuclear antibody
Antifilaggrin
Anti-Sa antibody
Antii- CCP (Cyclic citrullinated Peptide) - lead marker for
detection of RA
Immune complex IgG-IgM deposited in joints resulting in type
III hypersensitivity.
C1 bind to immune complex- activate classical complement
cascade
C3a AND C5a act as chemotactic factor- chronic -
inflammation
-
– damaged tissue
Antibodies are against Citrullinated proteins which are
generated by modification of protein bound arginine by the
enzyme peptidylarginine deiminase
RA
LAB DX OF RA
Clinical manifestation
Radiographic findings
Laboratory testing
RF –
Agglutination:IgM only
Sheep RBC coated with IgG
Latex particles – predominant because it is more sensitivity
EIA - IgG, IgA, IgM
Nephelometry - IgG, IgA, IgM
- scattering light of immune complex
Anti-CCP
EIA
TREATMENT FOR RA
Anti-inflammatory (Ibuprofen and salicylates)
Control local swelling and pain
Disease Modifying Antirheumatic Drugs (DMARDS)
Methotrexate
Hydroxychloroquine
Sulfasalazine
Leflunomide
Penicillamine
Corticosteroid (prednizone)
-halt inflammatory response
TNF-α blocker
1. Monoclonal antibody (infliximab, adalimumab)
2.. TNF-α receptor fused to an IgG molecule
(etanercept)
Rituximab – targets CD20 antigen on B cells
Autoimmune Thyroid Disease
- Hashimoto’s Thyroiditis
- Grave’s Disease
HASHIMOTO THYROIDITIS SIGNS AND SYMPTOMS
AKA Chronic Autoimmune thyroiditis
S/S
Goiter
Hypothyroidism
Dry skin
Decreased sweating
Puffy face with edematous eyelids
Pallor with a yellow tinge
Weight gain
Dry brittle hair
Thyroid autoantibodies
GRAVE DISEASE S/S
Hyperthyroidism`- most common cause
Thyrotoxicosis with goiter
Clinical symptoms
Nervousness
Insomnia
Depression
Weight loss
Heat intolerance
Sweating
Rapid heartbeat
Palpitations
Breathlessness
Symptoms
Exophthalmus
Graves disease - Antibody
- Thyroid-stimulating hormone receptor Antibody (TSHRab)
- Thyroid Peroxidase antibody
- Thyrotropin receptor-blocking antibody
THYROID DISEASE LAB RESULTS
Presence of
1. Thyroglobulin antibodies - Hashimotos
IIF – less sensitive but detect non agglutinating antibodies
- substrate: methanol fixed monkey cryostat tissue sections
Passive Hemagglutination – tanned red blood cells
2. Thyroid peroxidase antibodies-Hashimoto’s and Grave’s
Against enzyme that catalyzes tyrosine iodination
EIA
IIF
Particle agglutination
3. TSH receptor antibodies – Grave’s disease
Bioassay- require tissue
Binding assay –competition between radiolabeled TSH and patient
autoimmune antibody
4. Colloid antibody (CA2)
5. TSH binding inhibitory immunoglobulin
EGENTIC AND ENVIRONMETNAL CAUSE OF DM
Genetic: associated with HLA-DR3 and DR4, DQ (DQβ)
Substitution for the amino acid 57 (Aspartic acid) of β chain
Environmental:
Viral infection
Rubella virus
Cytomegalovirus
Coxsackie B4 virus
Early exposure in Cow’s milk
may act as antigen presenting cells
to activate T helper cells. Th1 then
generates TNF-α, IFN-λ and IL-1.
IN DM
B CELLS
Diabetes Mellitus - Autoantibodies
- Anti-insulin antibodies
- Antibodies to GAD enzyme
- Islet cells antibodies ( ICAs)h
- Antibodies to
Insulinoma antigen 2 (IA-2or ICA 512)
IA-2βA (Phogrin)
Diabetes Mellitus – Lab Dx
Islet cell Ab
IIF – frozen section of human pancreas
RIA
Anti-insulin , Anti-GAD
RIA
EIA
Diabetes Mellitus - Tx
Insulin (IV)
Immunosuppressive agents
Cyclosporin A
Azathiorpine
Prednisone
Anti CD-20 (Rituximab) –under research
Multiple Sclerosis
Inflammatory, Autoimmune , CNS
Formation of Plaques in the white matter of the brain and
spinal cord, leading to destruction of Myelin Sheathe of
axons
Genetic: polymorphism in the gene coding for IL-7
Viral:EBV,measles, Herpes simplex, Varicella, Rubella,
Influenza C, Human Herpes Virus-6, Para influenza virus
Multiple Sclerosis- S/s
Visual disturbances
Diminished dexterity of limbs
Locomotors incoordination
Dizziness
Facial palsy
Tingling “pins and needles” of the spine or extremities
Flashes of light seen in eye movements
Pathogenesis OF MULTIPLE SCLEROSIS
Th1 (IL-1,TNF-α, INF-λ)
Th2 (IL-4,IL-5, IL-10)
Changes in endothelium to allow T cell
To penetrate BBB
Demyelination: predominant cells: T cells
and macrophage .Attachment of antibody to
myelin membrane
Acute inflammation; injury to axons and glia,
structural repair with recovery of some function
; post inflammatory neurodegeneration
LAB RESULT OF MULTIPLE SCLEROSIS
- Oligoclonal Banding
Increased Ig in the CSF~ CSF protein electrophoresis
Presence of atleast 4 bands - CSFprotein electrophoresis
- Isoelectric focusing with immunoblotting – more sensitive
- CSF igG index
Compares the amount of IgG of spinal fluid to serum
Not specific
ANTIBODIES IN MULTIPLE SCLEROSIS
Antibodies against
1. Myelin basic protein peptides
2. Components of oligodendrocytes
3. Myelin membranes
Autoimmune disease that affects the neuromuscular junction
Weakness and fatigability of skeletal muscle
Myasthenia Gravis
S/S OF MYASTHANIA GRAVIS
Early signs:
Drooping of eyelids
Inability to retract the corners of the mouth “snarling”
Symptoms
Speaking
Chewing
Swallowing
Inability to support trunk, neck, head.
Associated with presence of SLE, RA, Pernicious Anemia,
thyroiditis
Myasthenia Gravis
GENETIC DEFECT IN MYASTHENIA GRAVIS
Early onset (<40 yo) – HLA antigen, A1, B8 and DR3
Late onset (>40yo) – HLA antigen B7
Men 30-60 – DR2
Thymic hyperplasia~ thymoma
Myasthenia Gravis - Lab Dx
- RIA
Blocks the binding of the receptors by anti-ACH receptor (ACHR)
Use α-bungarotoxin snake venom to irreversibly bind to ACHR
antibody
Precipitation is measured
Myasthenia Gravis - Tx
Anticholinesterase agent
Thymectomy
Corticosteroids
Azathioprine
cyclosporine
Presence of autoantibody to glomerular
basement membrane, renal tubular and
alveolar basement membrane, resulting to
renal failure and pulmonary hemorrhage
Usually occurs after viral infection
Goodpasteur’s Syndrome
Goodpasteur’s Syndrome
s/s of goodpasteur syndrom
Signs: Renal involvement
Gross or microscopic hematuria
Proteinuria
Dec 24-hour creatinine clearance
Inc serum BUN and Creatinine
Signs: Pulmonary
Hemorrhage
Dyspnea
Weakness
Fatigue
Cough
Antibody against noncollagenous region of alpha 3 chain
type IV collagen in glomerular and alveolar basement
membranes
autoantibody
Specific anti-basement antibodies
Formation of smooth, linear ribbonlike pattern on direct
immunofluorescent assay of glomerular basement membrane
lab results for goodpasteur syndrome
- RIA
- EIA
Alpha 3 sub unit to detect Ab
Less sensitive that WB - IIF
Frozen kidney sections that are incubated with patient serum and
then overlaid with fluorescein-labelled IgG
High false positive and negative - Western blot – confirmatory
Most sensitive and specific
treatment for goodpasteur syndrome
Plasmapheresis
Dialysis
Immunosuppressive drugs
Glucocorticoids
Cyclophosphamide
Azathioprin