Cytokines and chemokines that we found elevated in POTS patients, in contrast to our non-POTS group, and that have been related to autoimmune diseases, include not only IL-21, but also IL-1β, INFΥ, CD30, and IL-17 [49,50,51]. The gene discussed is TNFRSF8; the disease is postural orthostatic tachycardia syndrome.