CD4 and Autoimmunity: Persistent immune activation, as characterized by increased levels of helper T cell 9 (Th9), CD8+ effector T cells, naive B cells, and CD4+ effector memory T cells, and persistent proinflammatory responses, as evident from long-term elevation of various cytokines, contribute to the development of latent autoimmunity, latent poly-autoimmunity, or even overt autoimmunity, all of which can be a characteristic feature of patients with post-COVID syndrome [17,68].