Neurophysiological Features of Peripheral Nervous System Involvement and Immunological Profile of Patients with Primary Sjögren Syndrome

Objective The aim of this study was to evaluate the prevalence, type of neuropathy, and the relationship between the presence of autoantibodies and neuropathy development in patients with primary Sjögren syndrome (pSS). Methods Sixty-one patients with pSS underwent a complete neurological and electrophysiological examination as well as immunological tests including rheumatoid factor (RF) and autoantibodies such as antinuclear antibodies (ANA), anti-Ro/SSa, and anti-La/SSB antibodies. Results The axonal loss or demyelination were found in 39 patients (63.9%). Twenty-nine (47.5%) subjects fulfilled both clinical and electrophysiological criteria of peripheral neuropathy of predominantly axonal type. Seropositivity to both anti-Ro and anti-La antibodies was more frequently found in patients with normal nerve conduction study. Seropositivity to anti-Ro alone was present in the majority of patients with axonal neuropathy ( P < 0.05). The presence of RF was associated with several electrodiagnostic signs of demyelination ( P < 0.01). The ANA titer showed no independent association with neuropathy. Conclusion Peripheral neuropathy is a frequent complication in patients with pSS. Seropositivity limited to anti-Ro is associated with increased risk of axonal neuropathy in comparison to seropositivity to both anti-Ro and anti-La antibodies. Seropositivity to RF may contribute to demyelination.