CD19 and idiopathic pulmonary fibrosis: We showed a down-regulation of T lymphocytes (total CD3+ as well as CD4+ and CD8+, Figures 1A, B, D, E), and CD3-CD19- cells (likely NK cells, Figure 1C) in M-COV-1 and COV-ICU-1, compared to HC and IPF groups, while the B cell compartment did not exhibit any differences (Figure 1F).