Double - Negative ( CD 4 - CD 8 - ) T Cells From Adult T - ce l l Leukemia Patients

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8[doublenegative, DN], T-cell receptor [TCR] &). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S1 OO@ in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/ CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR