Hyperacute rejection of renal transplant is which type of hypersensitivity reaction: March 2007

Ans. B: Type II hypersensitivity reaction Type II reactions result when antibody binds to cellular or tissue antigens or to a molecule coupled to a cell or tissue. The antigen-antibody complex activates cells that paicipate in antibody-dependent cell-mediated cytotoxicity (e.g., NK cells, eosinophils, macrophages), complement, or both. The result is cell and tissue damage. Disorders involving type II reactions include hyperacute graft rejection of an organ transplant, Coombs'-positive hemolytic anemias, Hashimoto's thyroiditis, and anti-glomerular basement membrane disease (e.g., Goodpasture's syndrome). Disorders involving type IV reactions include contact dermatitis (e.g., poison ivy), hypersensitivity pneumonitis, Acute transplant rejection, TB, and many forms of drug hypersensitivity. Chronic graft rejection is type II and type III reaction. Graft versus host disease is a type IV reaction.