[Sjögren's syndrome associated with childhood-onset systemic lupus erythematosus]

Sjögren syndrome (SS) is a common autoimmune disease that exhibits broad organ-specific and systemic manifestations, the most prevalent being decreased lacrimal and salivary gland function, xerostomia, and keratoconjunctivitis sicca. Secondary SS occurs associated with autoimmune diseases, most commonly systemic lupus erythematosus (SLE). Thirty-four childhood-onset SLE patients (2 boys and 32 girls, mean onset age 11.5+/-2.6 years) were evaluated for the presence of secondary SS using the classification criteria for SS revised by Japanese Ministry of Welfare in 1999. Clinical manifestations, serological findings, and renal pathology in SLE patients complicated with SS (SLE+SS, n=14) were compared with those in SLE with no SS autoantibodies (Ro/SS-A or La/SS-B) (SLE-no SS antibodies, n=14). Of all 34 cases, 20 (58.8%) were with positive Ro/SS-A or La/SS-B antibody. Fourteen of the 20 (70.0%) were diagnosed as having secondary SS and all of them were subclinical SS with no sicca symptoms. However, findings of Schirmer test, salivary flow test and minor salivary gland biopsy were positive in 2 of 16 (13.3%), 5 of 16 (31.3%), and 14 of 17 (82.4%) patients, respectively. Compared with the SLE-no SS antibodies group, patients with SLE+SS showed higher level of serum IgG and had higher frequency of anti-U1 RNP antibody and significantly more severe renal involvement. The revised criteria is useful for diagnosis of SS in early stage before the development of exocrine gland damage and appears to be helpful for long term follow-up in childhood-onset SLE associated with SS.