ABSTRACT
The connective tissue diseases (CTDs) are a heterogeneous group of immuno-
logically mediated inflammatory conditions of unknown etiology, accompanied
by diverse autoantibodies and affecting multiple organ systems. In adults, the more
frequent CTDs comprise rheumatoid arthritis (RA), systemic sclerosis (SSc),
Sjo¨gren’s syndrome (SjS), systemic lupus erythematosus (SLE), polymyositis/
dermatomyositis (PM/DM), and mixed CTD (MCTD).
