Systemic Lupus Erythematosus: Presence in Human Serum of an Unusual Acid-Labile Leukocyte Interferon

Abstract

A previously undescribed species of human leukocyte, or alpha, interferon is present in the serum of many patients with systemic lupus erythematosus. It was shown to be alpha-interferon by neutralization with specific antiserums, affinity column chromatography, and antiviral activity on bovine cells. However, 23 of 30 interferon samples tested were inactivated by incubation at pH 2, a characteristic of human "immune," or gamma, interferon. Multiple samples of interferon from the same patient had similar biological properties, but samples from different patients were not all identical, suggesting that several variants of this species of human alpha-interferon may exist.