Anti-NuMA1 and anti-NuMA2 (anti-HsEg5) antibodies: Clinical and immunological features: A propos of 40 new cases and review of the literature

Objective Anti-NuMA1 and anti-NuMA2 antibodies are antinuclear antibodies (ANA) targeting the mitotic spindle apparatus. Our objective was to determine their clinical and immunological features and to review the literature available data. Patients and methods Between 2004 and 2008, 36,498 sera were analyzed for the presence of ANA, which included anti-NuMA1 and anti-NuMA2 antibodies. Clinical and immunological features of patients with positive anti-NuMA1 and anti-NuMA2 antibodies (titer ≥ 1/320) were retrospectively collected and analyzed. A review of the literature was secondly performed. Results Out of the 36,498 sera analyzed, 10,585 sera were positive for ANA (29%). Out of ANA positive sera, 40 sera (0.38%) (40 different patients) were positive for anti-NuMA antibodies: 27 anti-NuMA1 (0.26%) and 13 anti-NuMA2 (0.12%). Compared to anti-NuMA2 positive patients, anti-NuMA1 positive patients were more often female (81.5% versus 46%; P = 0.03), had more frequently a connective tissue disease (CTD) (40.7% versus 0%; P = 0.016) and higher serum titers (877 ± 466 versus 443 ± 278; P = 0.007). The anti-NuMA1 positive CTD were either Sjögrenʹs syndrome (SS) (54.5%) or systemic lupus erythematosus (SLE) (45.5%). In the literature, 164 anti-NuMA positive patients (133 anti-NuMA1 and 31 anti-NuMA2) have been reported. Combining the reported cases to ours, up to 67.5% of anti-NuMA positive patients had an autoimmune disease, mostly pSS in 34% (31/90) and SLE in 31% (28/90). Anti-NuMA1 antibodies were the single positive ANA in 46% of anti-NuMA1 positive SS and 47% of anti-NuMA1 positive SLE, and anti-NuMA2 antibodies in 2/2 and 87.5%, respectively. Conclusion Detection of anti-NuMA1 and anti-NuMA2 antibodies is very uncommon. When present, they are mostly associated with connective tissue disease, mainly Sjögren syndrome and systemic lupus. Clinicians may be aware that in these latter conditions, anti-NuMA antibodies may be the single serological marker.