Ultra-sensitive detection of rare T cell clones

► We sequence T cell receptors from a million T cells isolated from human blood samples. ► Spiking in T cell clones, we show the assay reliably detects 1 cell in 100,000. ► The assay is shown to precisely measure clone quantities from 10 to 100,000 T cells. ► We present a series of experiments to show that the assay is repeatable.