Pancytopenia secondary to hemophagocytic syndrome in rheumatoid arthritis treated with methotrexate and sulfasalazine.

Hemophagocytic syndrome is an exceptional cause of pancytopenia. Its etiologies are most commonly viral or bacterial infections, lymphoproliferative syndromes, acquired or congenital immunodeficiencies, systemic diseases, or immunomodulatory treatment. We describe a patient with rheumatoid arthritis (RA) treated with methotrexate (MTX), sulfasalazine, and low dose corticosteroids, whose case was seriously complicated by the occurrence of acute febrile pancytopenia. The pancytopenia appeared secondary to hemophagocytic syndrome triggered by Escherichia coli septicemia. The evolution was marked by severe aggravation of RA, probably due to release of cytokines from macrophages (tumor necrosis factor-alpha, interleukin 6). Reintroduction of MTX (without sulfasalazine) resulted in partial remission and there was no reappearance of new hematological anomalies after 16 month followup. A knowledge of this syndrome is particularly important, since it mimics drug toxicity and other complications such as lymphoproliferative diseases.