Are cytokines and chemokines suitable biomarkers for Takayasu arteritis?

There is a growing need for disease related biomarkers in Takayasu arteritis (TA).The assessment of pro-inflammatory cytokines and chemokines in TA may provide a better understanding of its pathophysiology, and circulating levels of these mediators may act as biomarkers of disease activity. Serum level of interleukin 6 (IL-6) is a potential biomarker for TA, which is mostly associated with TA status and disease activity. Associations between TA and serum/plasma levels of other cytokines are less clear. mRNA expression of IL-4 and tumor necrosis factor α (TNFα) are constitutively increased in peripheral blood mononuclear cells (PBMC) from TA patients and the expression of both cytokines increases even more after PBMC stimulation in vitro, while the expression of IL-10 mRNA decreases. In addition, circulating T cells from TA patients produce increased levels of both Th1- and Th17-related cytokines upon in vitro stimulation. In the aorta from TA patients, an increased expression of interferon γ (IFNγ), IL-6, IL-12 and IL-17 has been described. Regarding circulating chemokines in TA, serum/plasma levels of IL-8 (CXCL8), CCL2 and CCL5 were shown to be elevated in TA patients compared with healthy controls as well as in TA patients with active disease compared with those in remission. Serum IL-6 seems to be the best biomarker for disease state and disease activity in TA and increased Th1 and Th17 responses are predominant in the pathophysiology of TA.