Activation of the complement system through the alternative pathway is necessary for the development of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in animal models C5a has ...

Your complement system consists of a group of important proteins in your bloodstream. These proteins help your immune system fight off harmful invaders, such as bacteria, and other foreign substances.

Complement component 3, often called C3, is an essential protein of the immune system. This protein plays a vital role in the body’s innate immune system, providing: the first line of defense against ...

A complement blood test checks for autoimmune diseases or other issues with your immune system. Your doctor might test you if you have a family history of certain conditions, such as rheumatoid ...