IFNG and hypertensive disorder: This is supported by the demonstration of increased levels of circulating IgG in the serum of hypertensives.51, 52 Increased numbers of central memory CD8+ T cells, activated CD8+ T cells producing interferon gamma (IFNγ) and tumour necrosis factor (TNF), TH17 cells53 interleukin (IL)-2, IL-6, and IL-754 have also been reported in patients with hypertension.