Hemophagocytic syndrome associated with rheumatoid arthritis

We report a patient with rheumatoid arthritis (RA) who showed bicytopenia with hyperferritinemia and hepatic dysfunction ascribable to hemophagocytic syndrome (HPS) 2 weeks after commencement of bucillamine. Pathology of the bone marrow showing infiltration of macrophages confirmed the diagnosis of HPS. On the basis of renal dysfunction with an increase in fibrin degradation products, disseminated intravascular coagulation was considered to be concurrent with HPS. Oral prednisolone and cyclosporine A were started right after cessation of bucillamine, and yielded complete normalization of hepatic and renal function and hematology. As there was neither disease activity of RA nor associated infection throughout the clinical course, bucillamine was suspected of being the cause of HPS in our patient. HPS is a very rare complication in RA, but should be actively considered when abnormalities in laboratory data, especially pancytopenia and hepatic dysfunction, quickly worsen.