EMD group 2, containing mostly HDs and RDs, was enriched for naïve B cells (IgD+CD27−, cluster 10) and CXCR5+IgD−CD27+ switched memory cells (cluster 2), and indeed, clusters 2 and 10 were statistically reduced in COVID-19 patients (Fig. 4P). The gene discussed is CXCR5; the disease is COVID-19.