[Transient leukemoid reaction of plasma cells in a patient with rheumatoid arthritis].

A 69-year-old female with rheumatoid arthritis was admitted to our hospital with facial flushing and cervical lymphadenopathy on Jan, 2006. She had been treated with methotrexate (MTX), sulfasalazine (SSA) and prednisolone. The MTX and SSA were discontinued because of appetite loss just before admission. The patient's white blood cell count was 30100/microl with 32.5% of plasma cells, and 25.7% of plasma cells were observed in the bone marrow. Immunoelectrophoresis revealed polyclonal hypergammaglobulinemia on admission. Flow cytometry analysis revealed that the plasma cells in the bone marrow expressed CD38 and CD19 and did not express CD56. The lymphadenopathy and the increase of plasma cells in the peripheral blood and the bone marrow gradually decreased after the cessation of MTX and SSA.