Common variable immunodeficiency mimicking rheumatoid arthritis with Sjögren's syndrome

Several autoimmune diseases have been reported to be associated with common variable immunodeficiency disease (CVID), including rheumatoid arthritis and Sjögren's syndrome. On the other hand, approximately 20-30% of patients with rheumatoid arthritis develop secondary Sjögren's syndrome. A 26-year-old woman had a 6-year history of chronic symmetric polyarthritis and 3-year history of sicca syndrome prior to admission for pneumonia. Rheumatoid arthritis with secondary Sjögren's syndrome had been diagnosed 1 year before. The patient had experienced 3 episodes of pneumonia during the previous 3 years. Markedly depressed serum immunoglobulin levels prompted a suspicion of common variable immunodeficiency, and the impression was confirmed after a series of examinations. Monthly administration of intravenous immunoglobulin (IVIG) alleviated the polyarthritis and improved the sicca syndrome. IVIG replacement therapy was ultimately successful in curing recurrent bacterial infections, chronic polyarthritis, and improving the severity of sicca syndrome.