Intravenous Immunoglobulins for the Treatment of Primary Sjögren's Syndrome Associated Painful Sensory Neuropathies

Inclusion Criteria: * Age ≥ 18 years and \< 80 years * Primary Sjögren's syndrome defined as per the European and American criteria (5) * Peripheral neuropathy clinically defined: * Pure sensitive (lymph node disease) or sensorimotor neuropathies * Proved EMG * Renal function, and viral evaluation (VIH and hepatitis serology) : \*Clairance \> 50 (In case of biological abnormality, the second dosage can be scheduled within 2 weeks) * Effective contraception during the study period * Patient capable of understanding information about the study and of giving his/her consent * Patient informed of the preliminary medical exam results * Patient with healthcare insurance * Written consent signed Exclusion Criteria: * Peripheral neurological damage of the type vascularitis-related multiplex mononeuropathy * Small fibers neuropathy * Neuropathy suspected of being related to alcohol, diabetes or post-chemotherapy * Chronic viral infection (HCV, HBV, HIV, etc.) * Prior treatment with polyvalent intravenous immunoglobulins in the 6 months preceding the study * Corticosteroid treatment at a dose greater than 20 mg/d of prednisone equivalent or no stable dose for at least 1 month before inclusion * Conventional immunosuppressant treatment with azathioprin, cyclophosphamide or mycophenolate mofetil on-going or interrupted less than one month before inclusion * Rituximab or other biotherapy (belimumab, tocilizumab, …) less than 6 months before the start of the study treatment * Im…