Introduction: The clinical associations of NuMA and HsEg5 antibodies, the main anti-mitotic spindle apparatus autoantibodies, remain unclear due to their extremely low prevalence.
Patients and methods: We have analysed the clinical data of 40 anti-NuMA- (0.87 per thousand) and 7 anti-HsEg5- (0.15 per thousand) positive patients detected during routine immunofluorescence examination of 45,804 sera. NuMA reactivity was further confirmed by immunoblotting.
Results: Antibodies to HsEg5 did not associate with any specific pathology. NuMA positivity associated with a diagnosis of connective tissue disease (CTD) in 18 patients (45%), primary Sjögren or sicca syndrome and undifferentiated connective tissue disease being the most represented. Seven patients (17.5%) were diagnosed with different organ-specific autoimmune diseases, whereas in the other 15 patients (37.5%), no autoimmune pathology could be documented.
Conclusions: Therefore, although both anti-mitotic spindle apparatus antibodies are not associated to a defined autoimmune pathology, the presence of NuMA antibodies, mainly at high titers, may be an indication for a more extensive screening of CTD.