In 1994, the team of Tchernev and Petrova from Alexandrovska Hospital in Sofia examined a female patient with liver cirrhosis caused by chronic Hepatitis C virus (HCV). They were intrigued by the patient’s many extra-hepatic manifestations — vascular lesions on the lower limbs, acute pain in the joints, intense tingling of the fingers, and extreme labor-impairing fatigue. They were also intrigued by the presence of cryoglobulins in the patient’s blood.