Among lymphocytes, CD19+ B cells were slightly decreased in patients who recovered from COVID-19 as compared with healthy controls, while an increase in CD8+ T cells was evident in patients who recovered from COVID-19 as compared both with those in the acute phase and with healthy controls (Supplemental Figure 1A; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.146701DS1). This evidence concerns the gene CD19 and COVID-19.