Immunology of Autoimmune Disease Flashcards
monogenic disorder
single gene defect causes an autoimmune disease eg IPEX syndrome
IPEX
characterised by overwhelming systemic autoimmunity
symptoms of IPEX
severe infections, diarrhoea, eczema, very early onset insulin dependent diabetes mellitus
when does IPEX present
early childhood
what is the treatment for IPEX
cure: hematopoietic stem cell transplantation
supportive care: Is drugs plus total parenteral nutrition
what is IPEX caused by
mutation in FOXP3 gene - essential for the development of regulatory T cells
how is IPEX passed on
X linked
describe central and peripheral tolerance mechanisms in normal people
central - removal of self reactive lymphocytes in primary lymphoid tissues
peripheral - inactivation of self reactive lymphocytes that escape central tolerance
what are Tregs
regulatory T cells that modulate the immune system and prevent autoimmune diseases
what happens to Tregs in IPEX
failure of peripheral tolerance due to defective regulatory T cells (Tregs)
do Tregs modulate central or peripheral tolerance
peripheral
what does mutations in FOXP3 gene cause
loss of function of regulatory T cells - uninhibited T cell activation
what is the influence of HLA genes in autoimmune disease
1000s of variants of HLA genes - some variants are associated with inc risk of developing a specific autoimmune disease
how do T cells recognise antigens
when they are presented by MHC(HLA) molecules
what causes the sex differences in autoimmune diseases
different hormonal influences on lymphocyte function
alteration of the course of some autoimmune diseases during pregnancy
molecular mimicry
similarities between foreign and self peptides are sufficient enough to result in the cross activation of autoreactive T or B cells by pathogen derived peptides - can contribute to autoimmune disease
name 4 potential mechanisms for autoimmune disease
molecular mimicry
antigen sequestration
super antigens
unrelated bystander activation
unrelated bystander activation
t and b cells just activated - dk why
antigen sequestration
a sequestered antigen (one that is not recognised by the immune system) is released due to trauma etc
what do superantigens cause
hyperresponsiveness eg TSST-1 in TSS
what type of hypersensitivity reaction is SLE
III
what type of hypersensitivity reaction is RA
IV
what happens in glomerulonephritis associated with SLE
deposition of IgG and complement C3 in granular pattern
what happens in glomerulonephritis associated with goodpastures
linear deposition of IgG along the glomerular basement membrane
