Detection of long SARS-CoV-2 nucleocapsid sequences in peripheral blood monocytes collected soon after hospital admission

ABSTRACT

Many viruses infect circulating mononuclear cells thereby facilitating infection of diverse organs. Blood monocytes (PBMC) are being intensively studied as immunologic and pathologic responders to the new SARS-CoV-2 virus (CoV19) but direct evidence showing CoV19 in monocytes is lacking. Circulating myeloid cells that take up residence in various organs can harbor viral genomes for many years in lymphatic tissues and brain, and act as a source for re-infection and/or post-viral organ pathology. Because nucleocapsid (NC) proteins protect the viral genome we tested PBMC from acutely ill patients for the diagnostic 72bp NC RNA plus adjacent longer (301bp) transcripts. In 2/11 patient PBMC, but no uninfected controls, long NCs were positive as early as 2-6 days after hospital admission as validated by sequencing. Pathogenic viral fragments, or the infectious virus, are probably disseminated by rare myeloid migratory cells that incorporate CoV19 by several pathways. Predictably, these cells carried CoV19 to heart and brain educing the late post-viral pathologies now evident.