To ensure that these conspicuous, age-related impacts on the αβ T cell compartment did not simply reflect lower numbers of sequences recovered (a potentially confounding variable in lymphopenia), each sample was subsampled to 1,200 (CD8+) or 2,400 (CD4+) cells (samples with fewer than these numbers of cells were excluded), and medians of metrics that were computed from 100 such resamples were reported as “subsampled” values. Here, CD4 is linked to lymphopenia.