Case Study 37: An odd reaction to sun Flashcards
What symptoms are typical of systemic lupus?
Sudden onset rash (florid rash on cheeks and bridge of nose, but not nasolabial folds) after exposure to sun, pain in joints and myalgia
Which classification of autoimmune disease is lupus?
Systemic autoimmune disease targeting multiple organ systems - affects all age groups but adults > children; females > males
Which cell type hyper reactivity is observed in systemic lupus erythromatosus (SLE)?
B cell hyper reactivity
What is the trigger event for SLE?
Unknown - but UV light can aggravate
What is the immunopathology present in SLE?
Immune complex deposition in basement membrane damages tissues especially synovium, glomeruli and small blood vessels
What type of hypersensitivity is SLE?
Type III
What is tissue injury the result of?
Leucocyte activation and inflammation
What part of the immune system is activated on basement membranes in SLE?
Complement cascade
Which autoantibodies are present in SLE?
Wide range of anti-self antibodies
Anti-nuclear antibodies (ANA), including DNA, ribonuclear proteins, histones and nuclear antigens.
How is SLE diagnosed?
By reacting patient serum with cells from Hep-2 cell line and recognising binding of antibodies in serum by their reaction with fluorescently labelled Abs against human Ig.
What information does the ANA test provide?
Antibodies against component of nuclei are commonly present
Not very specific, but highly sensitive, because many individuals make these antibodies but are unaffected.
Which ANAs are often tested for?
Anti-dsDNA
Anti-ribonuclear proteins (RNP)
Blood components (erythrocytes, lymphocytes, platelets, etc.)
What does B cell tolerance in the periphery rely on?
Lack of CD4 T cell stimulation to selectively activate those B cells that bind epitopes.
Why is a dip stick test used in diagnosis of SLE?
TO test for SLE-associated kidney failure
Glomerular nephritis can be caused by immune complex deposition
How might ANA and other intracellular antibodies be generated?
If cells apoptose → immunological ignorance
Death of cells by other causes (UV, trauma) → exposure of immune cells to necrotic cells
