The slightly lower recovery of CD4+ TRB CDR3s from patients with active COVID-19 likely reflects COVID-19–associated T cytopenia that was particularly severe for CD8+ T cells and Vδ2+ T cells (16, 25, –27) and that was reflected in TRB and TRD showing the poorest sequence recoveries from the CD4− fraction (Fig. 1B). The gene discussed is CD4; the disease is COVID-19.