Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by multisystem inflammation, autoantibody production, and diverse clinical manifestations affecting the skin, joints, kidneys, nervous system, and other organs.

Definition

Epidemiology

Affects approximately 20–150 per 100,000 individuals globally
Female-to-male ratio approximately 9:1
Most commonly affects women of childbearing age (15–45 years)
Higher prevalence in African American, Hispanic, and Asian populations
Incidence peaks in young adulthood
Genetic predisposition plays a significant role
Associated with increased morbidity and risk of organ damage over time

Etiology

Multifactorial: combination of genetic, hormonal, and environmental factors
Genetic susceptibility: HLA-DR2, HLA-DR3, complement deficiencies (C1q, C2, C4)
Autoantibody production: ANA, anti-dsDNA, anti-Sm, anti-Ro/SSA, anti-La/SSB
Environmental triggers: UV light, infections, certain medications (drug-induced lupus)
Hormonal influences: estrogen may contribute to higher female prevalence
Immune dysregulation leading to loss of self-tolerance
Complement activation and immune complex deposition cause tissue damage

Pathophysiology

Autoantibody production against nuclear, cytoplasmic, and cell surface antigens
Immune complex deposition in skin, kidneys, joints, and blood vessels
Complement activation leading to inflammation and tissue injury
Dysregulated T and B cell activity sustaining chronic autoimmune response
Chronic inflammation causing fibrosis and organ damage
Microvascular injury contributes to systemic manifestations
Multisystem involvement results from interplay of autoimmunity and inflammation