Hemophagocytic syndrome in a patient with rheumatoid arthritis

A 63-year-old female, who had been diagnosed with rheumatoid arthritis (RA) 3 years previously, was admitted due to progressive pancytopenia, lymphadenopathy, fever, and weight loss. The physical and laboratory findings fulfilled all of the American Rheumatism Association (ARA) revised criteria for RA. Her bone marrow aspirate revealed a decreased nuclear cell count (1.8 x 10(4) microliters) and megakarocyte count (0/microliter), and macrophages phagocytizing blood cells (4%), indicating the presence of hemophagocytic syndrome. The serological tests for several viruses revealed no obvious viral etiology. However, a slight Epstein-Barr virus (EBV) reactivation could not be excluded. Administration of 40 mg prednisolone daily improved her abnormal hematological findings and immunological laboratory parameters. This is a case of RA accompanied by hemophagocytic syndrome, which has not been reported previously as a complication of RA.