[Gougerot-Sjögren syndrome. Risk of lymphoma]

LYMPHOMA RISK: Lymphoma is a very severe complication of primary Sjögren's syndrome: 5 to 10% of patients followed for more than 10 years will develop a lymphoma. Predictive factors include serum monoclonal immunoglobulins or cryoglobulins and a B clone population in accessory salivary glands. TYPICAL CLINICAL AND HISTOLOGICAL PRESENTATION: Mucosal involvement (parotid as well as gastric or pulmonary localizations) is frequent. According to the recent classification of lymphomas, most lymphomas developing in patients with Sjögren's syndrome are B lymphomas of the marginal zone: MALT lymphomas or low-grade nodal monocytoid lymphomas which are sometimes not identified until transformation to the giant cell stage. SIMILARITIES WITH HEPATITIS C LYMPHOMAS: The pathophysiology of lymphoma in Sjögrën's syndrome remains unknown. To date, there is no argument favoring a viral infection or a deregulation of a unique oncogene or anti-oncogene. Certain similarities between lymphomas in Sjögren's syndrome and lymphomas associated with hepatitic C virus would suggest a common pathogenisis: possibly a permanent stimulation of auto-reactive B cells carrying a surface immunoglobulin with rheumatoid factor activity in the target organs of the autoimmune disease. These B lymphocytes would then proliferate secondarily.