In vivo expression of B7-H6 on inflammatory monocytes during sepsis and association of B7-H6 and sepsis conditions. Flow cytometric analysis of B7-H6 expression on CD45⁺CD14⁺CD19⁻CD3⁻ monocytes, gated from PBMCs of (A) sepsis patients, (B) SIRS patients, and (C) healthy donors. Cells are stained with CD14, CD16 mAbs, and directly conjugated 17B1.3 anti–B7-H6 mAbs (black histograms) or mIgG1 isotype control (gray histograms). Data are representative of 15 sepsis patients (23 patients in total), 9 SIRS patients, and 14 healthy donors. (D) Concentrations of sB7-H6 in the sera of sepsis patients, SIRS patients, or healthy donors were measured by ELISA. Statistical analyses were performed using the Student t test. (E) Sepsis patients were stratified according to the nature of their sepsis (induced by Gram⁺LPS⁻ or Gram⁻LPS⁺ bacteria), and concentrations of sB7-H6 were measured by ELISA. Statistical analyses were performed using the Student t test. (F) Kaplan-Meier curves of survival probability obtained by segregating the whole cohort of ICU patients into 2 groups according to the expression of B7-H6 cell-surface expression. The number of the specimen is indicated on the graph. Statistical analyses were performed using the Pearson X2 test. mB7-H6⁺, B7-H6–positive cells; mB7-H6⁻, B7-H6–negative cells.