Acute leukemia following cyclophosphamide therapy for Sjögren's syndrome.

A fatal myeloproliferative syndrome diagnosed as subacute myelomonocytic leukemia developed in a patient with Sjögren's syndrome following treatment with cyclophosphamide. Although patients with Sjögren's syndrome have a recognized increased risk of developing lymphoproliferative disorders, particularly reticulum cell sarcoma, there is no evidence to support a similar predisposition to leukemia. As immunosuppressive therapy is becoming more common in the treatment of patients with rheumatoid arthritis, there have been recent reports of patients developing fatal myeloproliferative disorders after receiving immunosuppressive therapy. Review of these cases shows similar duration of therapy, and cyclophosphamide, among others, has been implicated as the leukemogenic agent in other patients. We feel that great caution should be exercised in the use of immunosuppressive drugs in patients with chronic, nonfatal disorders sich as rheumatoid arthritis and Sjögren's syndrome.