ICOS and synovial sarcoma: Due to the heterogeneity in marker combinations used to identify peripheral Tfh-cells in patients with SS in previous works,28 40–44 we performed a comprehensive analysis of Tfh-like cell subsets in peripheral blood matched with SG on the basis of the expression of CXCR5, ICOS and PD-1 coupled with intracellular cytokine analysis.