Abstract
BACKGROUND: Mitotic spindle apparatus (MSA) antibodies are rare findings with undefined clinical significance in clinical research. We aimed at investigating the prevalence and clinical significance of anti-MSA antibodies in Chinese population. METHODS: Between 2008 and 2013, a total of 180,180 patients were studied for the presence of anti-MSA antibodies. The clinical details and laboratory data of anti-MSA-positive patients were retrospectively collected and analyzed. RESULTS: Of the 180,180 patients tested, 68,640 patients presented with positive antinuclear antibodies (ANAs, 38.10%), but only 32 patients with positive anti-MSA antibodies (0.018%). Diagnoses were established in 22 of 32 patients: 16 connective tissue diseases (CTDs), mainly Sjogren syndrome (SS, 5/16), rheumatoid arthritis (RA, 4/16), and systemic lupus erythematosus (SLE, 3/16), and 6 nonautoimmune conditions. The most frequent clinical symptoms of the anti-MSA-positive patients were arthralgia and eyes and mouth drying. Additionally, 70% of anti-MSA antibodies were not associated with other ANAs, however, when associated, the most frequent ANA was anti-SSA. CONCLUSIONS: Anti-MSA antibodies have a low prevalence and female gender predominance. Anti-MSA antibodies are primarily associated with CTDs, mainly SS, RA, and SLE. The presence of anti-MSA antibodies might be the unique serological markers of the CTDs, especially when anti-SSA, SSB, and dsDNA antibodies are negative, or the level of RF is low.