In fact, in vivo treatment with cytokine- or cytokine receptor-targeted monoclonal antibodies, such as anti-tumor necrosis factor α (anti-TNF-α) or anti-IL-6 receptor, has been shown to neutralize inflammatory cytokines while rescued Treg function in patients with rheumatoid arthritis and kidney transplant recipients, respectively [19,162,163]. Here, TNF is linked to rheumatoid arthritis.