Comparison of clinical, immunological and neuroimaging features between anti-aquaporin-4 antibody-positive and antibody-negative Sjögren's syndrome patients with central nervous system manifestations

Background and objective: The objective of this study is to clarify clinical, immunological, and neuroimaging features in anti-aquaporin-4 (AQP4) antibody-positive and antibody-negative Sjögren's syndrome (SS) patients with central nervous system (CNS) involvement.Methods: Medical records and MRI scans were retrospectively analyzed in 22 consecutive SS patients with CNS manifestations.Results: Seven (31.8%) patients were positive for anti-AQP4 antibodies. The frequency of visual impairment was higher in anti-AQP4 antibody-positive patients than in antibody-negative patients (71.4% vs. 0.0%, p = 0.0008). Brain MRI showed that discrete lesions were more commonly found in the cerebrum, brainstem, and optic nerve in anti-AQP4 antibody-positive patients than in antibody-negative patients (p = 0.002, p = 0.006, and p = 0.004, respectively), while spinal cord MRI showed that posterior column lesions in the cervical spinal cord were more frequent in anti-AQP4 antibody-positive patients than in antibody-negative patients (71.4% vs. 14.3%, p = 0.01). SS-A antibody titers were higher in anti-AQP4 antibody-positive patients than in antibody-negative patients (p = 0.012) and were also higher in patients with longitudinally extensive spinal cord lesions (LESCLs) than in those without LESCLs (p = 0.019).Conclusions: In SS, the presence of anti-AQP4 antibodies is associated with involvement of the optic nerve, cerebrum and brainstem, and with cervical posterior column lesions in the spinal cord.