Clinical Immunology: Systemic Lupus Erythematosus

Study Notes

SLE is the most common connective tissue disease.
Around 90% of affected individuals are women.
The peak age at onset is between 20 and 30 years.
SLE usually presents with non-specific symptoms including fever, skin rash, arthralgia, oral ulcers, weight loss, hair loss, and Raynaud's phenomenon.

Malar rash: fixed erythema, flat or raised, sparing the nasolabial folds.
Discoid rash: erythematous raised patches with adherent keratotic scarring.
Photosensitivity: rash due to unusual reaction to sunlight.
Oral ulcers: oral or nasopharyngeal ulceration, which may be painless.
Arthritis: non-erosive, involving two or more peripheral joints.
Serositis: pleuritis (pleuritic pain or rub, or pleural effusion) or pericarditis (rub, effusion).
Renal disorder: persistent proteinuria > 0.5 g/day or cellular casts.
Neurological disorder: seizures or psychosis.
Haematological disorder: haemolytic anaemia or leucopenia, or lymphopenia, or thrombocytopenia.
Immunological disorder: anti-DNA or anti-Smith or antiphospholipid antibodies.
Antinuclear antibody (ANA) disorder: abnormal titre of ANA by immunofluorescence.

Mild to moderate SLE:
- Avoid exposure to sunlight and use sunblock.
- Use NSAIDs, hydroxychloroquine, and steroids.
- Consider Azathioprine, Methotrexate, and control of CV risk factors.
Life-threatening lupus:
- Methylprednisolone IV.
- Cyclophosphamide IV.
- Mycophenolate mofetil (MMF).
- Rituximab.
- Biologics: Belimumab.

Clinical syndrome presented mainly by recurrent miscarriages and recurrent arterial and venous thrombosis.
Characterized by the presence of anticardiolipin antibodies and lupus anticoagulants, which target protein C or β2-glycoprotein, leading to thrombosis.
May occur alone (primary APS) or in association with other autoimmune diseases like SLE, SSc, and RA.

Thromboembolic events: venous thromboembolism, arterial thromboembolism.
Adverse pregnancy outcome: recurrent first trimester abortion (≥ 3), unexplained fetal death after 10 weeks' gestation, and severe early pre-eclampsia.
Livedo reticularis, skin necrosis, and catastrophic APS (acute vascular occlusion in 3 different organs within a short time, less than one week).

Arterial or venous thromboembolic events.
Adverse pregnancy outcome (repeated abortions, premature labor, intrauterine fetal death).
Livedo reticularis.
Positive antiphospholipid antibodies (lupus anticoagulants, anticardiolipin antibodies, anti-beta2 glycoprotein) at least 3 months apart.

Primary prophylaxis against thrombotic events:
- Aspirin.
- Statins.
- Hydroxychloroquine.
- Vitamin K antagonists (Warfarin).
Secondary prophylaxis against thrombotic events:
- Vitamin K antagonists (Warfarin).
- The desired INR target: ≥ 2.
- Direct oral anticoagulants (DOAC): ±.
Treatment of APS during pregnancy aims to improve the pregnancy outcome:
- Aspirin + Heparin.
- Aspirin + Low Molecular Weight Heparin (LMWH).