TNF and long COVID-19: From a clinical perspective, a persistent expression of IFNs and other key immunological markers [Interleukin-6 (IL-6), Tumor Necrosis Factor- α (TNF-α), Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF), Macrophage Colony-Stimulating Factor (M-CSF)], as well as other signs of systemic inflammation, might contribute to immune injuries to several tissues and organs, which are prevalent in PASC [29].