SLE, drug hypersensitivity (penicillin), and infection are associated with which form of vasculitis?

SLE, drug hypersensitivity (penicillin), and infection are associated with which form of vasculitis?

• A. Immune complex associated vasculitis
• B. ANCA-associated vasculitis
• C. Kawasaki disease
• D. Giant cell arteritis

Answer: (A)

Immune complex deposition in small vessels drives this form of vasculitis. When antigen–antibody immune complexes form in circulation, they can deposit in vessel walls and activate complement, attracting neutrophils and causing inflammation and damage. This mechanism fits SLE, where autoantibody–antigen complexes circulate and deposit in multiple organs; it also explains penicillin-induced hypersensitivity reactions (serum sickness–type reactions) where drug-immune complexes trigger vascular inflammation; and infections can provide abundant microbial antigens that form immune complexes with antibodies, leading to leukocytoclastic vasculitis. In contrast, ANCA-associated vasculitis is driven by antibodies against neutrophil cytoplasmic antigens and is typically pauci-immune (little to no immune complex deposition). Kawasaki disease is a medium-vessel vasculitis in children with mucocutaneous features and a distinct pathogenesis, while giant cell arteritis is a large-vessel granulomatous vasculitis in older adults.

Immune complex deposition in small vessels drives this form of vasculitis. When antigen–antibody immune complexes form in circulation, they can deposit in vessel walls and activate complement, attracting neutrophils and causing inflammation and damage. This mechanism fits SLE, where autoantibody–antigen complexes circulate and deposit in multiple organs; it also explains penicillin-induced hypersensitivity reactions (serum sickness–type reactions) where drug-immune complexes trigger vascular inflammation; and infections can provide abundant microbial antigens that form immune complexes with antibodies, leading to leukocytoclastic vasculitis.

In contrast, ANCA-associated vasculitis is driven by antibodies against neutrophil cytoplasmic antigens and is typically pauci-immune (little to no immune complex deposition). Kawasaki disease is a medium-vessel vasculitis in children with mucocutaneous features and a distinct pathogenesis, while giant cell arteritis is a large-vessel granulomatous vasculitis in older adults.