CD62L/CX₃CR1 expression on peripheral Mo's from different clinical groups. Whole blood from HC (n = 11), patients with HUS (n = 13), UC (n = 6), and IC (n = 11) was stained with PECy5-labeled anti-CD14, PE-labeled anti-CD62L, and FITC-labeled anti-CX₃CR1, and analyzed by flow cytometry as described in “Patients, materials, and methods.” Mo subpopulations were defined according their CD14 expression, and those of CX₃CR1 and CD62L were depicted. (A) Representative dotplots from 1 child within each clinical group showing CX₃CR1 and CD62L expression on CD14⁺ Mo's. Dot plot quadrants are defined as: CX₃CR1⁺/CD62L⁺, top right; CX₃CR1⁻/CD62L⁺, top left; and CX₃CR1⁺/CD62L⁻, bottom right. The percentages of the different subpopulations are shown within each quadrant. (B) According to CX₃CR1 and CD62L membrane expression, 4 subpopulations were defined. Each bar represents the mean ± SEM of the percentage of cells for each subpopulation in HC (□), patients with HUS (▪), UC (▧), and IC () groups. (C) Each bar represents the mean ± SEM of the MFI of CX₃CR1 and CD62L expression for each Mo subset defined in panel A for HC (□), patients with HUS (▪), UC (▨), and IC (). *P < .05; **P < .01; *** P < .001 statistically different compared with HC. #P < .05; ##P < .01; ###P < .001 compared with children with HUS.