Chemokines and cell trafficking in Sjögren's syndrome.

Sjögren's syndrome is a chronic inflammatory condition affecting exocrine glands, manifested clinically as dry eyes and dry mouth. It arises secondary to systemic immune-mediated diseases such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), scleroderma or 'primary' Sjögren's syndrome. Histologically it is characterized by peri-ductal aggregates of CD4 T lymphocytes, the frequent occurrence of ectopic germinal centres and, in some patients, B-cell infiltration of ductal epithelium (myoepithelial sialadenitis). This latter lesion is the precursor for the development of low grade (MALT) B-cell lymphoma. The identification over recent years of chemokines and their receptors enables us to address the specific processes involved in the migration of inflammatory cells into exocrine glands, the development of their secondary structures and patterns of retention within the glands and potentially the subsequent transformation of B cells into mucosa associated lymphoid tissue (MALT) lymphoma.