CD4+T cells seem to be the moderator between sniffy Co-V2 and the bad stuff.  The CD4+T cells in some people have cross reactivity, meaning at least partial recognition, of coof from prior Corona type virus exposure, and can lead a moderated response - cross reactivity.  CD8+T cells get called early, B4 cells also get the message, and coof gets squelched through a mild cytokine and robust humoral [antibody] response.  This is moderated by interferon timing that differs if there isn't an existing CD4+T cell response.

 Some people express ACE2 receptors on CD4+T cells, and Co-V2 can infect those cells.  If the CD4+T cells are infected by Co-V2, they don't message the CD8+T or B4 cells into action the same way.  Co-V2 has more time to set up shop because part of the natural immune response isn't working, and it infects way more cells.  The large number of dying cells creates a different interferon response that may turn into a cytokine storm.