A 47-year-old male presents with fever, weight loss, muscle weakness, and severe abdominal pain. Physical examination reveals livedo reticularis (a purplish, net-like skin discoloration) on his lower extremities and multiple tender nodules. Laboratory tests reveal elevated erythrocyte sedimentation rate (ESR), elevated C-reactive protein (CRP), and significant proteinuria. A biopsy of the skin lesion shows necrotizing inflammation of medium-sized arteries with fibrinoid necrosis. Which of the following reaction mechanisms is primarily associated with this patient’s condition?
