Immune cytokine signatures of PASC patients reflect an ongoing chronic inflammation and angiogenesis with elevated plasma levels of IL-17a, stem cell factor, IL-12p70, IL-1β, macrophage inflammatory protein-1β (MIP-1β), brain-derived neurotrophic factor (BDNF), and VEGF223 Also, among other immune mediators, reduced levels of cortisol strongly correlate with pulmonary-PASC symptoms224. The gene discussed is BDNF; the disease is long COVID-19.