Systemic Lupus is a chronic autoimmune disease that can affect multiple organs and systems in the body. It occurs when the immune system mistakenly attacks healthy tissues, causing inflammation and damage to various parts of the body such as skin, joints, kidneys, brain, lungs, heart, and blood vessels. The condition is called "systemic" because it can affect many areas of the body at once. It's also known as SLE (Systemic Lupus Erythematosus).