Autoimmunity and Autoimmune Diseases Flashcards
Genetic factors associated with autoimmune disease?
Familial Incidence
Association with Specific HLA/MHC Haplotypes
Origins of autoimmune disease?
Genetics Failure to maintain self-tolerance Loss of Treg Expression of cryptic self epitopes Inappropriate MHC II molecules Antigen mimicry Polyclonal B activation Infectious Diseases Hormonal influences
Autoimmune hemolytic anemia.
Rxn Type, Autoantigen and Consequence?
Type II
Rh blood group antigens
RBC destruction, Anemia
Autoimmune thrombocytopenia purpura.
Rxn Type, Autoantigen and Consequence?
Type II
Platelet Integrin (gpIIb:IIIa)
Abnormal Bleeding
Goodpasture’s Syndrome.
Rxn Type, Autoantigen and Consequence?
Type II
Non-collagenous basement membrane, Type 4 collagen
Glomerulonephritis, Pulmonary Hemorrhage
Pemphigus Vulgaris.
Rxn Type, Autoantigen and Consequence?
Type II
Epidermal Cadherin
Blistering
Pemphigus foliaceus.
Rxn Type, Autoantigen and Consequence?
Type II
Desmoglein
Mild Blistering
Acute rheumatic fever.
Rxn Type, Autoantigen and Consequence?
Type II
Strep Wall antigens, cross react w/ cardiac
Arthritis, Myocarditis, Late Scarring of Heart
Grave’s Disease.
Rxn Type, Autoantigen and Consequence?
Type II
TSH receptor
Hyperthyroidism
Myasthenia Gravis.
Rxn Type, Autoantigen and Consequence?
Type II
Acetylcholine Receptor
Progressive weakness
Type II Diabetes.
Rxn Type, Autoantigen and Consequence?
Type II
Insulin Receptor
Hyperglycemia, Ketoacidosis
Subacute bacterial endocarditis.
Rxn Type, Autoantigen, and Consequence?
Type III
Bacterial Antigen
Glomerulonephritis
Mixed essential cryoglobulinemia.
Rxn Type, Autoantigen, and Consequence?
Type III
Rheumatoid Factor IgG complexes
Systemic Vasculitis
Systemic Lupus Erythematosus.
Rxn Type, Autoantigen, and Consequence?
Type III
DNA, Histones, Ribosomes, snRNPs
Glomerulonephritis, Vasculitis, Arthritis
Type I Diabetes.
Rxn Type, Autoantigen, and Consequence?
Type IV
Pancreatic beta cell antigen
beta cell destruction
Rheumatoid arthritis
Rxn Type, Autoantigen, and Consequence?
Type 4
Unknown synovial joint antigen
Joint inflammation, destruction
MS
Rxn Type, Autoantigen, and Consequence?
Type 4
Myelin basic protein, proteolipid protein
Brain degeneration, Paralysis
How do we normally prevent autoimmunity?
Positive/Negative Selection of B and T cells
Regulatory CD4CD25 T Cells
Physical Separation
Limited expression of MHC II and B7
Examples of physically separated from lymphocytes?
Brain, Eye, Testis
How are autoimmune cells repressed by Tregs?
IL10, TGFbeta
Five Major Susceptibility Factors in Autoimmune Disease?
HLA Genotype/Genetic Background Microbial Infection Injury Environmental Factors/Behavior Gender and Sex hormones
How might microbial infection promote autoimmunity
Adjuvant effect
Induction of higher MHC and B7
Molecular Mimicry
How might injury lead to an autoimmune response?
Reveals antigens from a previously immune priveledged organ
Environmental factors that affect autoimmune disease?
Smoking and hygiene
Which gender is more prone to autoimmune concerns?
Women
Describe the pathogenesis of Sympathetic Opthalmia
Injury in one eye releases eye antigen into local lymph nodes
Immune responses to antigen affect both eyes
Blindness in both damaged and undamaged eye
What does AIRE do?
Allows expression of peripheral antigen in the thymus
Mutation of AIRE leads to….
Wide range of autoimmune diseases
Mutations in AIRE are characterized by….
Autoimmune
PolyEndocrynology
Candidiasis
Ectodermal Dystrophy
What is IPEX?
Mutation of FOXP3
Loss of generation of Tregs
Tregs can’t suppress activation of other immune cells
Describe the relationship of HLA allotypes with aytoimmune disease
Some unique HLA allotypes are very heavily assoicated with specific disease states compared to their prevalence in the control population
Ex. B27 HLA is present in 9% of people, but more than 95% of patients with ankylosing spondylitis have it
What is Celiac disease?
Wheat flour gluten peptide-specific CD4+ T cells
Later anti-transglutaminase autoantibodies
Destruction of villi structure
How does Celiac Happen
Gluten degraded in lumen to resistant fragment Fragment enters gut tissue Deaminated by transglutaminase Native CD4 t cell responds via HLA-DQ Inflammatory T cell response
What happens in molecular mimicry?
Antibodies to pathogens cross-react against host antigens
Group A Strep
HLA Association? Consequence?
Not Known
Rheumatic Fever
Chlamydia trachomatis
HLA Association? Consequence?
HLA-B27
Reiter’s Syndrome (arthritis)
Campylobacter jejuni
HLA Association? Consequence?
HLA-B27
Reactive Arthritis
Borrelia Burgdorferi
HLA Association? Consequence?
HLA-DR2, DR4
Chronic Arthritis in Lyme Disease
Cocksackie A and B
HLA Association? Consequence?
HLA DQ2, DQ8, DR4
Type I Diabetes
Mechanism of induced autoimmune thyroid disease?
IFNg from infection/inflammation induces MHC II
Activated T cells recognize thyroid peptides
Induce Autoimmune thyroid disease
How does the thyroid typically avoid immune response?
Thyroid does not normally express HLA molecules
What is autoimmune hemolytic anemia (type 2)
Erythrocytes bind anti-RBC autoantibodies
Destruction through phagocytosis or completment
How do you treat autoimmune hemolytic anemia (type 2)
Splenectomy to reduce Blood cell loss
What happens in Immune Thrombocytopenic Purpura (ITP)
Antibodies attach to blood platelets for destruction
What is Goodpasture’s syndrome?
IgG agains alpha3 chain of type 4 collagen in BM
Renal Glom is most sensitive to the antibody deposits/inflam
HLA types associated with Type I diabetes?
HLA-DR3, DR4
Grave’s disease is associated with what HLA type?
HLA-DR3
Difference in presentation of Hashimoto’s and Grave’s?
Hashi - Destroys Thyroid
Graves – Hyperproduction of thyroid
Autoimmune disease of adrenal gland?
Addison’s
Treatment for Grave’s disease?
Thyroidectomy or destruction of the gland by radioactive I
Concern for pregnant women with Grave’s
Antibodies to TSHR can cross placenta
Newborn also suffers from Grave’s
Plasmaphoresis should cure the disease
What happens in Hashimoto’s thyroiditis?
Antibodies against effector T cells specific for thyroid
Destroy Thyroid, loss of T3/T4 production
Th1 type disease
Treatment for hashimoto’s
administration of thyroid hormone
List three autoimmune liver/GI diseases
IBD
Pernicious Anemia
Autoimmune Chronic Active Hepatitis
Autoimmune Chronic Active Hepatitis is assocaited with which HLA antigen?
HLA-B8/DR3
Three autoimmune rheumatic diseases? HLA? Sensitivity?
Rheumatoid Arthritis - DR4 – (III and IV)
Systemic Lupus Erythematosus – DR2,3 – II and III
Polymyositis/Dermatomyositis – DR3, DR – IV
Immediately apparent sign of systemic lupus
Wolf Erythematosus (Skin Rash) Caused by antibodies to histone and DNA
Two big problems with Systemic Lupus Erythematosus?
IgG binding to cell surfaces –> Inflammatory responses
Immune complexes deposited in vessels, kidneys
Cause of rheumatoid arthritis?
Rheymatoid Factor = IgM/G/A against the Fc region of IgG
Leukocyte infiltration in the joint synovium
What cells make rheumatoid factor?
Plasma B cells
How is Rheumatoid arthritis treated?
Anti inflamamtory
Immunosuppressive drugs
How does smoking affect Rheumatoid arthritis?
Smoking –> Injury –> Generation of Citruline Residues
Citruline residues –> CD4 T Cell Activation -> RA
How can RA be treated with NK cells?
Add in an anti-CD20 antibody (Rituximab) to promote lysis by NK cells
Four autoimmune neurologic diseases.
MS
Acute disseminated encephalomyelitis
Acute Inflammatory Polyneuropathy/Guillon Barre
Myasthenia Gravis
MS is what type of hypersensitivity?
2 and 4
Acute disseminated encephaloyelitis is what type of hypersensitivity?
4
Guillon barre is what type of hypersensitivity?
II and IV
Myasthenia gravis is is what type of hypersensitivity?
II
T cells implicated in MS?
Th17 or Th1
Cytokines associated with CNS inflammation and demyelination
IL-17, IFNg