In addition to the adverse effects of reduced ATP production by oxidative phosphorylation in mitochondria on T cells, the TCA cycle of CD4+ T cells in RA can be disrupted by disruptions that increase levels of upstream metabolites such as α-ketoglutarate, citric acid and acetyl coenzyme A, leading to loss of granulomatous activity inline T cells [26]. This evidence concerns the gene CD4 and rheumatoid arthritis.