Immunosuppressive Treatment for Mixed Connective Tissue Disease May Facilitate the Development of Adult T Cell Leukemia/Lymphoma in a HTLVI Carrier

A 66yearold woman who was positive for human Tlymphotropic virus type I (HTLVI) antibody developed mixed connective tissue disease (MCTD) with interstitial pneumonia, and was successfully treated with corticosteroid. One year later, under maintenance treatment of prednisolone (PSL), she contracted acute type adult Tcell leukemia/lymphoma (ATLL) without flaring of MCTD. MCTD is considered to be as one of the HTLVIrelated inflammatory diseases, however the development of ATLL during the treatment of HTLVIrelated MCTD has not been well studied. Here, we review the literature and raise the issue of the mutual interactions between MCTDcausative antiHTLVI immune response and antiATLL immune response.