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 ...

The complement system is a key component of innate and adaptive immunity and therefore acts as a vital defense against invading pathogens. Deficiencies in the complement system are associated with ...

A complement C4 (also known as a complement component 4, or simply C4) is a test to measure the level of C4 proteins you have in your blood. These proteins play a role in how your immune system ...

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.

It was called ‘complement’ because it aided the antibacterial activity of antibodies. However, it is now known that the complement system can be activated early in an infection without the presence of ...

Global understanding of complement has shifted and developed since the 21st century: from our idea of a blood-based antibiotic system to a global regulator of immunity and tissue homeostasis. Recent ...

Immunotherapy is increasingly becoming standard therapy in cancer, with technology, such as checkpoint inhibitors and cell therapy, raising the efficacy bar in many forms of the disease. But the ...

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 ...

Among people with sickle cell disease—an inherited blood disorder—acute chest syndrome (ACS) is the leading cause of death. The condition is the result of red blood cells becoming stiff, sticky, and ...

Faults in a certain part of the immune system might be at the root of some long covid cases, new research suggests. For many people, covid is an illness that blusters in and out of our lives as cases ...