Novel autoantibodies in Sjogren's syndrome.

Sjogren's syndrome (SS) is defined by autoantibodies to Ro and La. The current studies identified additional autoantibodies in SS to salivary gland protein 1 (SP-1), carbonic anhydrase 6 (CA6) and parotid secretory protein (PSP). These autoantibodies were present in two animal models for SS and occurred earlier in the course of the disease than antibodies to Ro or La. Patients with SS also produced antibodies to SP-1, CA6 and PSP. These antibodies were found in 45% of patients meeting the criteria for SS who lacked antibodies to Ro or La. Furthermore, in patients with idiopathic xerostomia and xerophthalmia for less than 2 years, 76% had antibodies to SP-1 and/or CA6 while only 31% had antibodies to Ro or La. Antibodies to SP-1, CA6 and PSP may be useful markers for identifying patients with SS at early stages of the disease or those that lack antibodies to either Ro or La.