Question

Explain why the Red Blood Cells of an individual are not normally destroyed as a result of innocent bystander lysis by complements?
When complement will cause lysis of an individual's own RBC?

Answer 1

Normally, the surface of RBC contains the markers - protein inhibitors of complement system, such as CD59.
When an individual organism acquires hypersensitivity its antibodies direct against antigens of the own RBC. The resulting Ag-Ab complexes activate complement, leading to cell lysis.