Adult T-cell leukemia after immunosuppressive therapy for systemic lupus erythematosus

Retroviruses, including human T-cell leukemia virus (HTLV)-1, are possible etiological factors for autoimmune diseases such as systemic lupus erythematosus (SLE) [1]. In particular, SLE patients can produce autoantibodies to the HTLV-1-related endogenous sequence (HRES)-1/p28 [2]. Adult T-cell leukemia (ATL) is a human malignancy associated with HTLV-1 and its diagnosis based on the clinicopathological findings and the presence of integrated HTLV-1 provirus in the DNA of tumor cells [3]. Here, we describe HTLV-1 carrier patient with SLE, who was presented with ATL after immunosuppressive therapy. The patient was a 63-year-old Japanese woman. Five years earlier, she had been diagnosed with SLE based on Raynoud’s phenomenon, polyarthralgia, malar rash, decreased serum complement levels, and positive results for antinuclear and anti-RNP antibodies. She was from Kyushu Island, a HTLV-1 endemic area in Japan, and was tested seropositive for HTLV-1. However, peripheral blood smear and bone marrow examinations showed no abnormalities. She was treated with high-dose steroids (intravenous 1,000 mg methylprednisolone daily for 3 days) followed by 20 mg dexamethasone, also daily. During the course of immunosuppressive therapy, she developed new flashing on her whole body with the occurrence of many abnormal cells in peripheral blood. Skin biopsy revealed the invasion of ATL cells. She was diagnosed with ATL. The time lag between the immunosuppressive therapy and the develop