Autoimmune Disease 2 Flashcards
Autoantibodies are not always?
Pathogenic
DiGeorge syndrome is due to?
Failur elf migration of 3rd and 4th branchial arches
Can cause thymocytes aphasia, congenital heart defects, cleft palate, absent parathyroid
IPEX immune dysregulation polyendocrinopathy enteropathic x linked?
Rare x linked mutation FoxP3 gene
Can cause iBD
HLA system is encoded on chromosome?
6
HLA system classes?
1- A,B,C
2- DR, DP and DQ
How many people are affected by coeliac disease?
1%
Manifestations of cealic?
Anaemia, vitamin deficiency, weight loss, loose stool, poor growth in children
What is coeliac disease?
Is autoimmune but triggered by exogenous antigen gluten
What do you see in coeliac disease microscope?
Villus atrophy, crypt hyperplasia, and lymphocyte infiltration
HLA- DQ2 and DQ8- both or either
What happens to gliadin?
Gut tissue transglutamine 2 enzyme to form gliadin peptide
HLA DQ2/8 present these peptides to T cells
How many Europeans express HLA-DQ2/8?
30-50%
Molecular mimicry?
Presentation of viral peptides or CD4 causes T cell activation
Viral peptide is similar to host derived peptide, T cell initiates inflammation
Autoimmune haemolysis after mycoplasma pneumoniae?
Mycoplasma antigen has homozygous to I antigen on red blood cells
IgM antibody to mycoplasma may cause transient haemolysis
Clinical onset of diabetes type 1 only happens when you have lost what percent of the pancreas?
90%
HLA class II alleles and risk?
DR3 or DR4 risk is 6
DR3 and DR4 risk is 15
Lupus seen mostly in?
Asian/ African descent, women
What predisposes to lupus?
Deficiency C1q, C2 and. C4 because can’t clear immune complexes
Pemphigus disease?
Thin walled Bullare on skin and mucus membranes- rupture easily
Target is the intracellular cement protein desmoglein 3 in superficial skin layers
Plasmapheresis?
Antibody is causing disease, therefore removal e.g vasculitis
Molecular mimicry?
Epitopes relevant to the pathogen are shared with host antigens
Conditions for molecular mimicry?
Correct MHC molecule to present epitope
Correct T cell to recognise it
What happens at molecular level in SLE?
Anti nuclear antibodies, apoptosis
Indirect immunoflourescence in blood
Solid phase immunoassay in blood
Direct immunofluorsence in tissues
Drugs for immunomodulation?
Systemic corticosteroids
Small molecule immunosuppressive drugs, methotrexate
Examples of molecular mimicry?
Autoimmune haemolysis after mycoplasma pneumoniae, homology to i antigen on rbc
Rheumatic fever, streptococcal infection then affects joints heart skin and brain
Protein 2C from coxsackie virus has homology with islet cell antigen glutamic acid decarboxylase
Presentation of lupus?
Butterfly rash Photosensitivity Hives Serositis- pleurisy, pleural effusion, pericarditis Renal Nephritis Pulmonary fibrosis Joint pain autoimmune cytopenia
SLE is most common in?
Women of reproductive age who are Asian and African descent
What may be the cause of lupus?
Antinuclear antibodies, and division apparatus
Immune complex disposition
Disordered apoptosis
Classical component deficiency 1,2,4
Indirect immunoflorescence?
Glass slide with tissue
Then patient serum with antibodies or not
Then detection antibody with fluorescent marker, then look through microscope
What happens in ELISA?
TgT solution Then samples with antibody Then anti igA antibody binding to igA Fc Convalenly linked to horse radish peroxidase Then trigger added
Pemphigoid?
Antibody mediated disease
Target is antigen at dermo-epidermal junction
Thick walled Bullae
Immunosuppressive drugs are?
Systemic corticosteroids
Methotrexate
Azathiprine
Cyclosporine
