The CyTOF density plots (visual stochastic neighbor embedding [viSNE]) revealed 2 subpopulations within Tregs, namely A and B. Their frequencies were distinct between healthy donors and patients with AA. Furthermore, patients with a higher Treg A frequency were less likely to respond to immunosuppression, and conversely, those with a higher Treg B frequency more likely to have a hematologic recovery following therapy. See Figure 2D in the article by Kordasti et al that begins on page 1193.