the 4 autoimmune connective tissue disorder/multisystem autoimmune rheumatic diseases
systemic lupus erythematosus
sjogren’s syndrome
systemic sclerosis (scleroderma)
autoimmune inflammatory muscle disease
SLE where does it cause inflammation
multi-site inflammation- joints, kidney, skin
autoimmune connective tissue disorders general points
Erosive, non-erosive?
What is typically seen in serum?
Common symptom/sign?
1)typically non-erosive (unlike Rheumatoid)
2)serum autoantibodies are characteristic
3) raynaud’s phenomenon
intermittent vasospasm of digits. triggered by cold exposures=triphasic colour change
Typical triphasic colour changes in Raynaud’s phenomenon
WHITE -> Vasospasm leads to blanching of digit
BLUE -> Cyanosis as static venous blood deoxygenates
RED -> Reactive hyperaemia
SLE clinical features
swan neck deformity/malar rash
raynaud’s
arthralgia
thrombocytopenia/haemolytic anaemia
Anti-nuclear antibodies (ANA) how to use results
Negative ANA effectively rules out SLE
However, ANA is not specific for lupus
1)+ve ANA
2)report strength (- max dilution which ab can still be detected) and pattern (autoantigen the ab are reacting to)
3) specific autoAb test to identify what ANA are reacting to:
Anti-ds-DNA ab
Anti-Ro
Anti-La
Anti-smith
Anti-RNP
which is stronger and by how much in dilution: ANA 1:320 and ANA 1:80
ANA 1:320 is three times stronger than ANA 1:80
Antiphospholipid (APL) antibodies- where do they target
antibodies directed to phospholipids on cell membrane
Antiphospholipid (APL) antibodies are associated with ↑ risk of:
1) Thrombosis
arterial (e.g. stroke)
venous (e.g. deep vein thrombosis, DVT)
2) Pregnancy loss (miscarriage)
antiphospholipid antibody how to measure in lab
measure in clinical lab: anticardiolipin antibodies, anti-beta2glycoprotein 1 antibodies
Persistent presence of APL + a clinical event
“anti-phospholipid antibody syndrome”
primary anti-phospholipid antibody syndrome is:
Anti-phospholipid antibody syndrome in absence of SLE
what is anti-double stranded DNA antibodies (anti-dsDNA) significant in
specific for SLE
Serum level of ab correlates with disease activity
anti-Sm ab significance
specific for SLE
serum level of ab does NOT correlate with disease activity
anti-Ro ab
anti-La ab
significance
secondary to sjogren’s syndrome
neonatal lupus syndrome
what is seen in neonatal lupus syndrome
transient rash in neonate
permanent heart block
Rheumatoid arthritis auto-antibody
RF
Anti-cyclic citrullinated peptide antibody
(Anti-CCP is a type of ACPA)
SLE - immunopathogenesis
which are innate and which adaptive
innate immunity:
overactivity of type 1 interferon (ie.IFN-a) pathway/
complement pathway abnormalities
adaptive immunity:
autoreactive B+T cells
Gene expression studies compared lupus patients to healthy controls found overexpression of genes activated downstream of the type 1 interferon receptor binding-> “interferon gene signature.” what is a high interferon gene signature associated with
worsen disease
what does (not available in UK yet) can block type 1 interferon receptor to treat SLE
anifrolumab
SLE- waste disposal hypothesis. how is the immune system generating a response to nuclear antigens? (should be hidden inside the cell)
SLE investigations
high ESR
normal CRP
measure urine protein (uPCR)
creatinine
albumin
kidney biopsy if proteinuria
ANA
Anti dsDNA ab
complement consumption- low C3/C4
Antiphospholipid AB
SLE-measuring disease activity
what is shown in unwell pt with active lupus
-what is their C3/C4/ anti-dsDNA ab levels
low complement C3/C4
High anti-dsDNA antibodies
SLE management: for all pt? mild/serious disease? renal disease?
hydroxychloroquine- All pts
steroids-acute flare
mild-hydroxychloroquine
serious-immunomodulatory agent (methotrexate)
renal disease-mycophenolate+/-rituximab