Expression of TCR Vβ transcripts in HLA-E tetramer–positive cells and PBMCs from HTLV-1–infected individuals and seronegative controls, analyzed by RT-PCR. The relative amounts of Vβ transcripts in whole PBMCs (hatched bars) and HLA-E tetramer–positive cells (black bars) were quantified by fluorescence with Genescan software. Arrows indicate monoclonal or oligoclonal spectratype bands (see “Patients, materials, and methods” for definition of oligoclonality).