Rheumatology Flashcards
(134 cards)
Causes of inherited CTD
Marfan’s syndrome
Ehlers-Danlos syndrome
Osteogenesis imperfecta
Alport’s syndrome
Causes of autoimmune CTD
SLE
RA
Sjogren’s
PM/DM
MCTD
Scleroderma
Overlap/UCTD
HLA region which strongest links with development of autoimmune CTD
HLADRB1
HLA class II sits on what chromosome
Chromosome 6
HLA class I sits on what chromosome
Chromosome 15
HLA class II presents to which cell
CD4 T cells
HLA class I presents to which cell
CD8 T cells
Function of HLA class II
Recognition of self
Presentation foreign peptides to CD4 cells
Role of HLA in SLE
Both HLA-DR and HLA-DQ loci implicated in SLE, particularly HLA-DRB1
Ethnic differences in HLE loci for SLE
Higher risk of SLE in African American and Hispanic for HLA DRB11503 and HLADRB108
Protective risk of SLE in Caucasian for HLA DRB1*0301
Effect of race on clinical manifestations of SLE
Non Caucasian ethnicities significantly higher frequency of lupus nephritis, neuropsychiatric SLE, severe haematologic manifestations and APLS
Asian ethnicities increased prevalence and severity, increased renal disease and increased auto-antibodies
SLE in Australian Indigenous population
Prevalence 2-4x of Caucasians
High disease activity and higher incidence of LN
Tend to have higher morbidity and mortality
Predisposing genes in SLE
HLA genes
STAT 4
Others include IRF5, IRAK1, TNFAIP3, SRP1, TLR7
Environmental factors that contribute to SLE
Oestrogen - can stimulate type 1 IGN pathway (whilst progesterone inhibits it), higher risk of autoimmunity
UV light - higher rate of formation of auto-antibodies
Microbiome
Infection - EBV, CMV, COVID
Major pathways of signalling B and T cells in SLE
Overexpression of IFN (biggest one)
Overexpression of neutrophils
Overexpression of plasmablasts
Role of type I interferon in SLE
Type I IFN is produced in response to a viral infection - acts as an alarm signal
- produced by most cells, but particular APCs
- induced by viral nucleic acid
Recruiter of T cells, B cells and neutrophils
Cytokines involved in SLE
TNF –> neutrophil recruitment, monocyte activation, sustains type I IFN expression
IL-6 –> B cell proliferation
IL-17 –> recruitment of inflammatory cells
IL-10 –> B cell proliferation, loss of tolerance
BAFF –> B cell survival (CD19, CD20), T cell activation
IFN Type 1
Role of Type 1 IFN in SLE
Reduction of Treg cells - loss of tolerance
Increase NETs - IL-17, inflammation
Increase BAFF - B cell proliferation, loss of tolerance
In SLE, type I IFN is initially produced in response to
Production of host nucleic acids
Dermatological and MSK manifestations of SLE
Malar rash
Photosensitive rash
Discoid rash
Subacute cutaneous lupus erythematosus
Periungal erythema/capillary dilatation –> pathogenic Raynaud’s
Alopecia
Mucosal ulcers - PAINLESS
Charcot’s arthropathy - reversible, non erosive arthritis
Classes of lupus nephritis
Class I - mesangial immune deposits without hypercellularity
Class II - mesangial immune deposits with hypercellulary
Class III - focal proliferative (<50% of glomeruli)
Class IV - diffuse proliferative (>50% of glomeruli)
Class V - membranous
Class VI - advanced sclerosing lesions
Indications for treatment of lupus nephritis
Class III-V indicated for treatment (proliferative/membranous)
Class I-II - treatment not required
Class IV - treatment refractory
Clinical manifestations of CNS lupus
Seizures
Headaches
Stroke syndromes
Transverse myelitis
Coma
Dementia
Ataxia
Rigidity, tremor
Chorea
Aseptic meningitis
Psychiatric disorders
SAH
Hemiballismus
Cranial neuropathy
Peripheral neuropathy
Mononeuritis multiplex
MS-like disorder
GBS
MRI findings on CNS lupus
T2 white matter lesions
- sensitive but not specific
- does not correlate to disease activity