MMP9 and vascular disorder: Following reports of MIS-C and PCC, we hypothesized that the cryptic pro-inflammatory and pro-fibrotic tone from reduced ACE2 expression in blood cells might intersect with additional plasma biomarkers of equally cryptic vasculopathy and fibrosis to further clarify individual risks of PCCs in the population., We selected TIMP-1, PIIINP and MMP-9 for assay from among MMP biomarkers reported as abnormal during acute COVID.