VMC 221: Veterinary Immunology and Serology (1+1)

TYPE-II HYPERSENSITIVITY REACTIONS TO DRUGS

• Red cells may be destroyed by three mechanisms in drug induced hypersensitivity.
  • The drug and antibody may combine and directly activate complement and red blood cells are destroyed in a bystanded effect as activated complement components bind to nearby cells.
  • Some drugs may adsorb on to the red cells. Since these cells are then modified, they may be recognized as foreign and eliminated by an immune response. Drugs like Penicillin, Quinine, L- DOPA, Aminosalicylic acid modify RBC and make them as non-self, resulting in autoimmune response and haemolysis. 
  • Drugs like cephalosporin may modify red cell membrane and they adsorb antibody and then removed by phagocytic cells.

  • Sulfonamides , phenylbutazone , aminopyrine and chloramphenicol modify granulocytes  resuting in granulocytosis or granulocytopaenia.

  • Sulfonamides , phenylbutazone and chloramphenicol causes thrombocytopaenia.