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 ...

Long Covid patients suffer from chronic symptoms such as fatigue or shortness of breath. As researchers have discovered, this is to some extent due to a part of our immune system called the complement ...

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 ...

Most people infected with the SARS-CoV-2 virus recover after the acute illness. However, a significant proportion of infected individuals develop long-lasting symptoms with a wide range of ...