We have previously reported that IL-6 is the most important cytokine to distinguish between attack and remission in patients with FMF in addition to those with FMF attacks and to healthy individuals.[6] These findings suggest that IL-6 may be useful as a biomarker for FMF and that tocilizumab (TCZ), which specifically inhibits IL-6 signal, may be useful as a therapeutic agent. Here, IL6 is linked to familial Mediterranean fever.