"Ghostbusters" star Harold Ramis has died at 69 years old, United Talent Agency confirmed to ABC News today.
Ramis was known as much for his off-screen work -- writing the "Ghostbusters" films, along with "Groundhog Day" and "Analyze This" -- as he was for playing Dr. Egon Spengler in front of the camera.
Ramis was surrounded by family in his Chicago home, where he's lived since 1996, when he died early this morning from complications of autoimmune inflammatory vasculitis, his wife Erica Mann Ramis told the Chicago Tribune.
The disease that led to actor-director Harold Ramis' death is one of an often-mysterious family of maladies that can starve organs and cause painful tissue damage.
Vasculitis develops when the body's immune system turns on its network of veins and arteries. Blood vessels become inflamed, restricting the flow of blood or cutting it off entirely, according to the National Institutes of Health. The disease can also cause an aneurysm, potentially leading to dangerous internal bleeding.
"Basically, the arteries can be leaking, they can be blocked or broken, and that all causes problems," said Dr. Peter Merkel, a rheumatologist and director of the Penn Vasculitis Center at the University of Pennsylvania medical school. "If you interrupt the blood supply, whatever organ or tissue is being supplied downstream is unhappy."