CCL2 and infection: Specifically, in scRNA-seq data sets, an increased abundance of monocyte-derived macrophages was associated with increased transcriptional expression of CCL2/3/4 and IL1B, as well as several members of the tumor necrosis factor superfamily (TNF, TNFSF10, TNFSF12, and TNFSF13B), in severe infection compared with moderate COVID-19 and/or healthy controls.26,49 Importantly, the proteins encoded by these genes all have receptors in thoracic hDRG, and thus their increased expression in BALF may modulate sensory innervation in the lung.