Introduction: Systemic lupus erythematosus and Sjögren's syndrome are multisystemic autoimmune diseases which can be associated to each other.
Objective: To investigate if there are any distinct clinical, laboratory or serologic features due to the association of the two diseases that can influence the follow up of these patients.
Patients and methods: The authors proved the association of these two autoimmune diseases in 56 patients, and these patients' clinical, laboratory and immunoserologic alterations. 50 patients with Sjögren's syndrome and 50 patients with systemic lupus erythematosus were used as control groups.
Results: Compared with Sjögren's syndrome alone, in the cases of the association of the diseases, rheumatoid factor was present less frequently, Ro/SS-A, La/SS-B and DNA antibodies were present more frequently, such as antiphospholipid autoantibodies and antiphospholipid syndrome. Anaemia, leukopenia and lymphopenia were detected more often and the patients were younger than in Sjögren's syndrome. Also, affection of the lung, kidney, skin, central nervous system and serous membranes are more common. The group with systemic lupus erythematosus differs in being older, having thyroiditis, Ro/SS-A, La/SS-B and DNA more frequently.
Conclusion: Definitive clinical, laboratory and serological features make the difference between the association of the two diseases and the diseases observed alone.