Antibodies patrol the body for invaders such as bacteria and viruses and tag them for immune system attack. The immune system keeps “records” of previous encounters with pathogens, leaving traces of them in our blood.

Autoantibodies normally help clear dead or damaged cells following infection or injury, but can sometimes mistakenly target the body’s own healthy proteins. They are linked to many autoimmune diseases including type 1 diabetes, multiple sclerosis and rheumatoid arthritis.