P2RX4 and myalgic encephalomeyelitis/chronic fatigue syndrome: In 19 patients with CFS, who were studied during a 25 min cycling exercise to determine the amount of mRNA of metabolite-detecting genes (ASIC3, P2X4, P2X5), adrenergic genes (A2A, B-1, B-2, COMT) and immune system genes (IL-6, IL-10, TNF-α, TLR4, CD14), the activity of the genes encoding for ASIC3, P2X4, P2X5, B-1, B-2, COMT, IL-10, TLR4 and CD14 increased significantly in blood lymphocytes 30 min, 24 h and 48 h post-exercise[91].