Identification of CD8_CXCR5+ICOS+T cells in human lymphoma tissues. Frozen cells isolated from lymphoma biopsy samples were analyzed by flow cytometry. (A) Gating strategy to identify the CD8_CXCR5+ICOS+ subset. CD8 T cells were identified from viable CD3 T cells (live/dead-negative CD14 CD19⁻CD3⁺), then CXCR5 and ICOS coexpression was defined among viable CD8 T cells. (B) Percentage of CD8_CXCR5+ICOS+ cells among CD8 T cells in different lymphoma samples. (C) Percentage of CD8_{CXCR5−ICOS+} among CD8 T cells in cases containing CD8_CXCR5+ICOS+ cells (positive subgroup), compared with cases lacking CD8_CXCR5+ICOS+ cells (negative subgroup). ***P < .001.