I - Autoimmune & Autoinflammatory Diseases Flashcards
what causes auto inflamm or auto immune diseases
immunopathology i nthe absence of infection or pathogens
what part of the immune system is involved in auto inflam conditions
innate immune response eg neutrophils / macrophages
what part of the immune system is involved in auto immune conditions
adaptive immune response eg T / B cells
define auto immune disease
activation of aberrant T / C cell responses on primary and secondary lymphoid organs leading to breaking of tolerance with developmental of immune reactivity towards self antigens
what is characteristic of auto immune disease
auto ABs
name 4 ways in which DNA can affect proteins involved in the development of auto immune/inflamm conditions
genetic predispostion
somatic mutations occuring after conception
epigenetics
micro RNA
name 2 monogenic auto inflamm diseases
familial mediterranean fever
TRAPS
name 5 polygenic auto inflamm diseases
Crohns
UC
osteoarthritis
GCA
takayasu’s arteritis
are monogenic or polygenic auto inflamm/immune conditions more common
polygenic
name 3 mixed pattern diseases (both auto inflamm and immune)
axial spondyloarthritis
Psoriatic arthritis
behcet’s syndrome
name some polygenic auto immune conditions
rheumatoid arthritis
myasthenia gravis
pernicious anaemia
graves disease
SLE
PBC
ANCA
Goodpastures
name 2 monogenic auto immune diseases
ALPS
IPEX
what pathway problem is most common in monogenic auto inflam disease
abnormal signalling via cytokine pathways involving TNF alpha or IL1
Sx of monogenic auto inflamm disease
periodic fevers
inflam in joints / skin / CNS
high CRP / ESR
mucosal issues
what gene is abhorrent in FMF
MEFV
what is the inheritance of FMF
AR
who gets Muckle Wells syndrome (mongenic auto inflam)
kids
what protein is abhorrent in FMF
pyrin
what is the normal function of pyrin that is absent in FMF
negative regulator of inflammasome complex
pathogenesis of FMF
MEFV gene mutation
MEFV encodes pyrin-marenostrin (usually expressed in neutrophils)
failure to regulate cryopyrin driven activation of neutrophils
PC of FMF
periodic fevers for 48-96 hours
abdo pain - peritonitis
chest pain - pleurisy
arthritis
rash
complications of FMF
AA amyloidosis (serum amyloid A depositis in kidneys, liver, spleen) –> kidney failure
Ix for FMF & results
CRP - HIGH
serum amyloid A - HIGH
MEFV gene mutation
Tx for FMF
1st line = colchicine 500mcg bd
2nd line = IL1 blocker and TNF alpha blocker
what causes IPEX
abnormality of regulatory T cells due to Foxp3 mutation (needed for CD25+ Treg cells development) –> leads to autoreactive B cells
what causes ALPS
abnormality of lymphocyte apoptosis due to FAS pathway mutation –> failure of autoreactive B/T cell apoptosis
Sx of IPEX
endocrine Sx - DM, hypothyroidism, eczema, enteropathy (gut inflamm)
Sx of ALPS
high lymphocyte number
splenomegaly
large lymph nodes
complication of ALPS
lymphoma
are HLA associations stronger in auto inflamm or auto immune diseases
auto immune
do you get auto antibodies in auto inflam disease
NO
gene defect in Crohns
IBD1 gene on Chr 16 (NOD2 aka CARD-15)
what % of Crohns pts have CARD 15
30%
what is the increased risk of Crohns with someone with CARD-15 gene mutation
1.5 to 3x risk if 1 copy
14-44x risk if 2 copies
pathogenesis of Crohns
CARD-15 gene expressed in myeloid cells –> results in failure to clear bacteria leading to inflamm & immune cell activation at sites
Sx of Crohns
abdo pain
diarrhoea - blood, mucous, pus
fevers
malaise
Tx of Crohns
corticosteroids
anti TNF alpha AB
do you get auto ABs in mixed pattern auto inflam/immune disease
NO
what is the heritability of axial spondyloarthritis (aka ank spon)
90%
what genes are involved in development of ank spon
HLA B27 (50% of risk)
IL23R
ILR2
Sx of ank spon
sacroilitis / large joint arthritis
enthesitis
low back pain and stiffness
Tx of ank spon
NSAIDs
immunosuppresion - anti TNF alpha and anti IL17
are HLA molecules important in auto immune disease
YES
what is the susceptibility allele of goodpastures
HLA DR 15
what is the susceptibility allele of Graves disease
HLA DR3
what is the susceptibility allele of SLE
HLA DR3
what is the susceptibility allele of T1DM
HLA DR3/4
what is the susceptibility allele of RA
HLA DR4
name 2 common mutations in polygenic auto immune disease
PTPN 22
CTLA4
describe the pathway of polygenic auto immune disease
genetic polymorphisms –> loss of tolerance –> auto reactive T cells / auto AB formation –> immunopathology
what is type 1 hypersensitivity with eg
IgE mediated & immediate
eg anaphylaxis
what is type 2 hypersensitivity
cytotoxic hypersensitivity - antibody reacts with cellular antigen
what is type 3 hypersensitivity
immune complex hypersensitivity
- AB reacts with soluble antigen to form immune complex
what is type 4 hypersensitivity
delayed type hypersensitivity
- t cell mediated response
name 4 examples of type 2 hypersensitivity
goodpastures
pemphigus vulgaris
graves
MG
auto AB of goodpastures
collagen type 4 of BM
auto AB of graves
TSH R
auto AB of MG
ACh R
Sx of type 3 hypersensitivity reaction
cutaenous vasculitis –> purpura / rash
glomerulonephirits
arthritis
give an example of type 3 hypersensitivity reaction
SLE
autoAB in SLE
dsDNA
Sx of SLE
rash
glomerulonephritis
arthritis
example of type 4 hypersensitivity reaction
T1DM
autoAB in T1DM
pancreatic B cell
nervous, palpitations, heat intolerance, diarrhoea, exopthalmos. dx?
graves
what Ig mediates graves
IgG
can anti TSH R ABs in Graves affect foetus & how
YES - cross placenta to cause transient hyperthyroidism
lethargic, dry skin and hair, constipation, cold intolerance, fat face. dx?
hashimotos
auto AB in hashimotos
anti TPO / anti thyroglobulin
is it useful to test for anti thyroid ABs to diagnose Hasmotos?
NO - lots of ppl will have them but not have Hashimotos, so just check TFTs
tired, pale, mild numbness of feet. low Vit b12. Dx?
pernicious anaemia
cause of pernicious anaemia
ABs to parietal cells or intrinsic factor
–> no absorption of vit B12
Tx of pernicious anaemia
B12 injection - not oral as won’t absorb
what FBC result is seen in pernicious anaemia
macrocytic anaemia
anti TTG / anti endomyosial ABs. Dx?
coeliac
which IBD has the most auto AB and what is the auto AB
UC > Crohns
p-anca
anti nuclear ABs. Dx?
autoimmune hepatitis
PBC
anti SM / anti LKM ABs. Dx?
AI hepatitis
anti mitochondrial ABs. Dx?
PBC
p-anca ABs. Dx?
AI hepatitis
PBC
drooping eyelids, weakness, worse at the end of the day. Dx?
MG
pathogenesis of MG
ABs against ACh R
–> failure of nerve depolarisation
–> absence of muscle AP
what % of MG pts have anti ACh R ABs
75%
haemoptysis and AKI. Dx?
goodpastures
where is the auto AB found in goodpastures
lungs /kidneys
how is Goodpastures auto AB Ix
kidney biopsy with immunoflurescence
conditions with p-anca
ANCA associated vasculitis
- micrscopic poluyangiitis
- eosinophilic granulomatosis with polyangiitis
conditions with c-anca
ANCA associate vasculitis
- granulomatosis with polyangiitis
what is auto AB in RA
anti CCP - citrulinated peptide
what non genetic factors increase risk of RA
smoking
gum infections (P. gingivalis)
what is the specificity of anti CCP ABs to RA
95%
what is the sensitivity of anti CCP ABs to RA
60-70%
what is more useful in detection of RA, anti CCP ABs or rheumatoid factor RF
anti CCP - more specific
generalised arthralgia, particularly small joints of hand. hair falling out. mouth ulcers. butterfly rash. dx?
SLE
process of SLE formation
ABs find to antigen to form immune complexes
complexes deposit in skin / joints / kidneys
immune complexes activate complement
complexes stimulate cells expressing Fc and complement Rs
how does immuneflurescence staining of type 2 hypersensitivity (AB mediated) vs type 3 (immune complex) differ
type 3 is lumpy, type 2 is smooth
what is the normal AB titre
1:80
specificity of dsDNA ABs in SLE
95%
sensitivity of dsDNA ABs in SLE
60-70%
how does dsDNA AB titre relate to disease progression in SLE and what is the use of this
high titres = more severe disease
–> good for disease monitoring
what does a low complement C4 level represent in SLE
active disease
what 4 Ix are done for monitoring in SLE
anti dsDNA AB
C3 / C4 complement
ESR
recurrent thrombosis / miscarriages. Ix? Dx?
anti-phospholipid ABs: anti-cardolipin, anti-beta2 glycoprotein 1, lupus anti coagulant
anti-phospholipid syndrome
dry eyes, dry mouth, enlarged parotid gland. Dx?
Sjogrens
complication of sjogrens
MALT lymphomas
ABs for Sjogrens
anti nuclear AB
anti Ro / La
Sx for limited cutaneous systemic sclerosis
CREST
- calcinosis
- raynauds
- esophageal dysmotility
- sclerodactyly
- telangectasia
assoication of limited cutaneous systemic sclerosis
primary pulmonary HTN
which is worse, limited cutaneous or diffuse systemic sclerosis & why
diffuse
- get kidney crises
auto ABs for limited cutaneous / diffuse systemic sclerosis
limited cutaneous = anti-centromere
diffuse = anti-topoisomerase
rash characteristic of dermatomyositis
helitrope rash on knees / forehead
contrast dermatomyositis with polymyositis
dermato = skin involved, CD4
poly = no skin involved, CD8
AB for dermatomyositis
ANA
what enzyme is cANCA associated with
proteinase 3
what enzyme is pANCA associated with
myeloperoxidase
which small vessel vascultiis is associated with cANCA
GPA
which small vessel vascultiis is associated with pANCA
MPA and EGPA