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 ...

Complement 3 glomerulopathy (C3G) is a rare kidney disease that affects your body’s innate immune system (complement system). Complement 3 glomerulopathy (C3G) is a kidney disease that’s caused by ...

We all forget things, and sometimes it would be better if we did not. Normal forgetting occurs more frequently as we age, but more serious, progressive, retrograde forgetting, which can have severe, ...

A new study published in the journal Science Immunology analyzed lung epithelial cells from patients infected with COVID-19 and found the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ...