GENETIC-DIFFERENCES BETWEEN PRIMARY AND SECONDARY SICCA SYNDROME

SICCA syndrome occurs alone or in association with another autoimmune disease, frequently rheumatoid arthritis. We recently proposed that sicca syndrome be termed primary when it occurs alone and secondary when it is associated with another autoimmune disease.1 This distinction is important because of the incidence of autoantibodies (against salivary ducts and extractable nuclear antigens) and certain clinical features are different in the two groups.2 3 4 Furthermore, we have observed that primary sicca syndrome appears to be associated with the lymphocyte defined as HLA-Dw3 allele, whereas sicca syndrome with rheumatoid arthritis is not.5 Thus, the clinical and serologic differences between these two. © 1979, Massachusetts Medical Society. All rights reserved.