The science of rheumatoid arthritis Flashcards
What happens to the joint in rheumatoid arthritis
Inflammation of the synovium due to inflammation - synovitis
The synovitis leads to the erosive damage of the bone and cartilage - on Xray the erosive damage is seen as marginal erosions
What is the definition of rheumatoid arthritis
Chronic, symmetric, polyarticular (5 or more joints) inflammatory joint disease that affects the small hands of the hands and feet
What is the rheumatoid synovitis characterised by
inflammatory cell infiltration - fibroblast proliferation and neoangiogenesis - development of new blood vessels
What does the synovial fluid in the joint cavity contain - especially in acute cases of rheumatoid arthritis
neutrophils
What antibodies are associated with rheumatoid arthritis
RFs - rheumatoid factors - and anti-citrullinated protein antibodies
Which antibodies are checked on suspected rheumatoid arthritis
Rheumatoid factor and anti-CCP antibodies
What is seropositive arthritis
they test positive for either rheumatoid factor or anti-CCP antibodies
What is seronegative rheumatoid arthritis
Testing negative for rheumatoid factor or anti-CCP antibodies - has a better prognosis
What gene is rheumatoid arthritis associated with
HLA-DRB1 locus
What enviromental factors can cause rheumatoid arthritis
smoking and bronchial stress - e.g exposure to silica
Infectious agents like viruses
What is citrullination
Conversion of amino acid arginine into the amino acid citrulline
How does citrillation lead to rheumatoid arthritis
When there is excessive citrullation, antigens form that can cause the formation of autoantibodies
What happens in synovitis in rheumatoid arthritis
Intimal lining hyperplasia and sublining infiltration of mononuclear cells - mainly immune and inflammatory cells
Macrophages in the lining are then activated
Fibroblasts proliferate
Synovial B cells produce antibodies
Dendritic cells present anigens to T cells in synovial germinal centres
Hypoxic conditions and cytokines cause new blood vessels to form (neoangiogenesis)
Cells are trapped in the joint and cannot leave
Neutrophils are present in the synovial fluid
What is the role of Chemokines in rheumatoid arthritis
Recruitment of inflammatory cells into the joint
What produces chemokines
macrophages and fibroblasts