Systemic lupus erythematosus
How the immune system normally ignores the contents of the body’s own cells, why in lupus it makes antibodies against nuclear material, and how immune complexes and complement inflame the skin, joints, kidneys, blood and serous linings.
By the end, you can
- Describe self-tolerance and the normal, quiet clearance of dying cells.
- Explain how genes, hormones and environmental triggers combine to break tolerance to nuclear antigens.
- Explain immune complex (type III) injury and complement consumption in lupus.
- Relate the rash, arthritis, serositis, kidney disease and blood changes to the mechanism.
- Interpret antinuclear antibodies, anti-dsDNA and low complement.
- Recognise the classic morphology (wire-loop lesions, haematoxylin bodies, Libman–Sacks endocarditis), the classification of lupus and lupus nephritis, and explain how the main drug classes act on the mechanism.
What it is
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease in which antibodies form against components of the cell nucleus, such as DNA and nuclear proteins. Immune complexes and complement inflame many organs, especially the skin, joints, kidneys, blood cells and the linings of the heart and lungs. It runs a course of flares and remissions and is about nine times commoner in women.
3 types to tell apart
- Systemic lupus
- Multiple organs involved; antinuclear antibodies present.
- Cutaneous lupus
- Skin only, such as discoid lupus with scarring patches.
- Drug-induced lupus
- Some medicines (for example hydralazine, procainamide) cause lupus-like disease that usually resolves when the drug stops.
Normal function
Keeping the cell’s contents out of view
Every day billions of cells die by apoptosis. Their contents, including the {{chromatin}} of the , are packaged into fragments that macrophages remove quickly and quietly, with help from complement proteins such as C1q, before the immune system responds.
Lymphocytes that strongly recognise self are deleted during development or held in check by regulatory T cells: self-tolerance.
So nuclear material, which is rich in DNA and RNA that can resemble viral signals, is normally never presented to the immune system as a threat.
Underlying change · Step 1 of 4
Tolerance to nuclear material breaks down
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
Immune complexes and complement
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
Many organs inflamed
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
Flares, tests and long-term risks
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .