Xu M, et al. - This is the first study describing the distribution of the subsets of circulating T follicular helper cells (cTfh cells) in Kawasaki disease (KD) patients with and without coronary artery lesions (CALs). Study participants included 20 KD patients and 15 healthy sex- and age-matched children. Investigators categorized circulating Tfh cells into three subsets by flow cytometry including cTfh1 (CXCR3 + CCR6-), cTfh2 (CXCR3-CCX6-) and cTfh17 (CXCR3-CCR6+) cells in circulating CD3 + CD4 + CXCR5 + CD45RA- T cells. According to the findings, CTfh2 cell frequency was significantly increased in KD patients prior to IVIG administration with low cTfh1 cell expression, where the cTfh2 + cTfh17/cTfh1 ratio increased significantly. The frequency of cTfh2 cells and the ratio significantly reduced while the frequency of cTfh1 cells significantly increased after intravenous immunoglobulin administration. They observed that cTfh1 and cTfh2 cells contribute to KD pathogenesis and that the two subsets could be linked with CALs.