232. SLE

Question 1

SLE Epidemiology (sex, race, age, risk factors)

Answer 1

Women in reproductive age (esp Black, Hispanic, Native American, Asian)
RF: Genes: several gene interactions
Environment: UV Light, Meds, Viral Infection, Cigarette smoking
Female Hormones (more activity during pregnancy)

Question 2

How does SLE lead to immune dysregulation?

Answer 2

• Genes + Environment = impaired clearance of apoptotic cells
• Dendritic cells present self
• Activate and sustain inflammatory response of autoreactive T/B cells
• Activation of Th17/Th2 T cells and autoreactive B cells - produce autoantibodies
• ICs form between auto-Ab and self - deposit everywhere promoting more inflammation

Question 3

What auto-antibodies are present in SLE

Answer 3

ANA: sensitive, not specific for SLE
anti-dsDNA: high spec to sle, assoc with nephritis
anti-Sm: high specific
anti-SSA/SSB - low spec but can cause neonatal SLE when cross placenta (HEART BLOCK IN UTERO)
anti-phospholipid - assoc with clotting

Question 4

How does SLE cause Kidney Damage? What kind of disease types in Kidney possible?

Answer 4

1. ICs caught in BM
2. direct binding of anti-Ab to BM
3. direct binding of anti-Ab to renal tubule

Membranous disease = subepithelial deposits
Proliferative Disease = subendothelial deposits

Question 5

Clinical Features of SLE

Answer 5

• malar rash
• discoid rash
• photosensitivity
• oral ulcers
• arthritis (inflammatory)
• serositis (pleura/pericardium)
• GN (proteinuria, RBC/WBC casts)
• neurologic disorder (seizures)
• hemolytic anemia
• ANA+
• anti-dsDNA, Sm, Phospholipid

Question 6

Current Tx of SLE (4)

Answer 6

1. Corticosteroids - for ACUTE flares (too many SE: osteoporosis, DM, HTN, cataracts)
2. Hydroxychloroquine - MAINSTAY Tx - decreases frequency and severity of flares
3. Immunosuppressants - severe organ involvement only (MTX, Tacrolimus)
4. Anti-coags if Anti-phospholipid positive (reduce clotting risk)