**1. Introduction**

Primary Sjögren's syndrome (pSS) is an autoimmune disease in which the symptoms resulting from inflammatory infiltrates in exocrine glands dominate. Frequently, patients complain of

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a feeling of sand under the eyelids, eye irritation, and red eye caused by a decrease in tear secretion. In pSS, other exocrine glands could be affected—among them: salivary glands, pancreas, vaginal mucous membranes, and glands of gastrointestinal tract or situated in bronchial tree. The patient may complain of dry mouth, dry vagina, and inflammation of the gastric and esophageal reflux. Dry cough may also occur. In the course of pSS interstitial changes in the lungs may occur with a progressive reduction of lung function and a failure of cardiovascular system (in conjunction with the development of right ventricular failure and pulmonary hypertension). Autoimmune inflammatory process may also involve peripheral and central nervous system, including cranial nerves, with symptoms of mixed sensory and motor neuropathy or multiple sclerosis (MS)-like symptoms. In pSS, B lymphocytes (B-cells) play a key role, with their hyperreactivity, leading to the overproduction of autoantibodies. Through the interaction between the cells, stimulation reaches T lymphocytes (T-cells), which are the first to form infiltrates in exocrine glands. The gradual destruction of the exocrine glands by the inflammation and by the autoimmune process causes the above- described symptoms [1].
