A Unique Antinuclear Antibody Staining Only the Mitotic-Spindle Apparatus

Abstract

To the Editor: During the performance of screening antinuclear-antibody tests using human epithelial cell substrate (HEp-2) at several institutions, a pattern of staining localized only to the mitotic-spindle apparatus was observed. We have called this pattern (staining of only centrioles and peripolar mitotic spindles, and not of cytoplasmic elements throughout the cell cycle) "antibody to the mitotic-spindle apparatus" (anti-MSA). The index serum was from a patient with osteoarthritis; over the past 14 months, 10 other patients have been shown to have anti-MSA, for an estimated frequency of eight in 10,000 screening tests. The 10 patients were women ranging in age . . .