 Preformed antibody (predominantly IgM) against donor red cell antigens not found in an individual of a particular blood group (e.g.anti-A IgM in an individual with blood group B), bind to the donor red cell surface and lead to rapid complement mediated haemolysis and potentially life-threatening clinical consequences.Another example of a complement dependent type II hypersensitivity reaction is Goodpasture's syndrome, where the basement membrane (containing collagen type IV) in the lung and kidney is attacked by one's own antibodies in a complement mediated fashion.