Memory cells (CD27+CD45RA-) that express PD-1 and CD38 (Pop0) and PD-1, CD38 and HLA-DR (Pop2), as well as CD27-CD45RAlow expressing PD-1, CD38 and HLA-DR (Pop6) were also expanded in COVID-19 patients (Figure 2G). The gene discussed is CD27; the disease is COVID-19.