Sjogren's Syndrome is an inflammatory autoimmune disease which causes dryness, especially of eyes and mouth. In autoimmune disease the immune system attacks itself causing inflammation and damage. Sjogren's Syndrome may occur primarily by itself or sometimes it can occur in association with a pre-existing disease like Rheumatoid Arthritis, Lupus or Myositis.

Sjögren's syndrome is the second most common rheumatic disease after rheumatoid arthritis. Its leading Practiceal manifestations are keratoconjunctivitis sicca and xerostomia. About 50% of patients with primary Sjögren's syndrome develop systemic manifestations including arthritis, Raynaud's phenomenon, lymphadenopathy, and lung involvement. Adult Still's disease is a form of polyarthritis with systemic manifestations seen in systemic juvenile rheumatoid arthritis. It is relatively rare, as is remitting seronegative symmetric synovitis with pitting edema (so-called RS3PE syndrome), another form of adult-onset polyarthritis that can occur in isolation or associated with polymyalgia rheumatica, hematopoietic malignancies, or even rheumatoid arthritis

You can find more information about Sjogren's Syndrome by clicking the link below:
http://www.rheumatology.org/public/factsheets/sjogrens_new.asp?aud=pat