Human antibodies specific for quinine and sulfamethoxazole promote platelet destruction in NOD/scid mice given these drugs. Human platelets suspended in plasma containing DDAbs or normal plasma were infused into NOD/scid mice followed by intraperitoneal injection of quinine (3.7 mg/kg; A) or sulfamethoxazole (50 mg/kg; B) at 0 and 5 hours. Platelet survival was markedly shortened in mice given DDAb and the appropriate drug (triangles), but not in mice given DDAb alone (squares) or drug plus normal plasma (circles). Values shown are the average of triplicate experiments ± 1 SEM. ***P < .001 relative to controls.