Sjogren's Syndrome (SS) is a common systemic autoimmune disease, including primary and secondary form. About 30% of RA are associated with sSS (1) Tumor necrosis factor alpha inhibitors (TNFa-Is) have been tried in this population without success. Abatacept (CTLA4-Ig) is comprised of the ligand-binding domain of CTLA4 plus human immunoglobulin and represents a novel therapeutic costimulation blocker that modulates the signal required for full T cell activation. Studies have shown that activated CD4 T cells play a role in the pathogenesis of SS, indicating Abatacept might be a useful therapeutic intervention in SS. Subjects who are receiving non-biologic immunosuppressive medications consisting of hydroxychloroquine, methotrexate (MTX), sulfasalazine, or leflunomide, at the time of enrollment will remain on these medications without dosage alteration. Efficacy and Safety data will be collected at the time of each clinic visit. The treatment closing date will occur 6 months after enrollment of each subject. Subjects will be followed at 1, 2, 3, 4, 5, and 6 months. Laboratory studies associated with the clinical trial will test potential autoantibody production for systemic autoimmune diseases.