Sjögren’s syndrome is an autoimmune disease in which the immune system attacks the body’s moisture-producing glands and tissues. These include the lacrimal glands that produce tears and the salivary glands, as well as mucus membranes in the nose and vagina. It develops when moisture-producing glands are damaged by activated immune cells, making them less able to respond to signals from the brain to produce tears or saliva. In addition, inflammatory cytokines may damage the nerves and neurotransmitters (chemical substance in the brain) that stimulate the tear ducts or salivary glands. About 90% of those with Sjögren’s syndrome are women.